Pub Date : 2026-01-29DOI: 10.1051/0004-6361/202557127
Q. Kral, J. Wang, J. Kammerer, S. Lacour, M. Malin, T. Winterhalder, B. Charnay, C. Perrot, P. Huet, R. Abuter, A. Amorim, W. O. Balmer, M. Benisty, J.-P. Berger, H. Beust, S. Blunt, A. Boccaletti, M. Bonnefoy, H. Bonnet, M. S. Bordoni, G. Bourdarot, W. Brandner, F. Cantalloube, P. Caselli, G. Chauvin, A. Chavez, A. Chomez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Davies, R. Dembet, J. Dexter, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, N. M. Förster Schreiber, P. Garcia, R. Garcia Lopez, T. Gardner, E. Gendron, R. Genzel, S. Gillessen, J. H. Girard, S. Grant, X. Haubois, Th. Henning, S. Hinkley, S. Hippler, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, P. Kervella, L. Kreidberg, N. T. Kurtovic, A.-M. Lagrange, V. Lapeyrère, J.-B. Le Bouquin, D. Lutz, A.-L. Maire, F. Mang, G.-D. Marleau, A. Mérand, P. Mollière, J. D. Monnier, C. Mordasini, D. Mouillet, E. Nasedkin, M. Nowak, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, N. Pourré, L. Pueyo, D. C. Ribeiro, E. Rickman, Z. Rustamkulov, J. Shangguan, T. Shimizu, D. Sing, J. Stadler, T. Stolker, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, A. Vigan, F. Vincent, S. D. von Fellenberg, F. Widmann, J. Woillez, S. Yazici, K. Abd El Dayem, N. Aimar, A. Berdeu, C. Correia, D. Defrère, M. Fabricius, H. Feuchtgruber, A. Foschi, S. F. Hönig, S. Joharle, R. Laugier, O. Lai, J. Leftley, B. Lopez, F. Millour, M. Montargès, N. Morujão, H. Nowacki, J. Osorno, R. Petrov, P. O. Petrucci, S. Rabien, S. Robbe-Dubois, M. Sadun Bordoni, J. Sánchez Bermúdez, D. Santos, J. Sauter, J. Scigliuto, F. Soulez, M. Subroweit, C. Sykes
Context. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions, as this field remains largely unexplored.Aims. We investigate whether the orbital motion of the companion HD 206893 B exhibits astrometric residuals consistent with the gravitational influence of an exomoon or binary planet.Methods. Using the VLTI/GRAVITY instrument, we monitored the astrometric positions of HD 206893 B and c on short (days to months) and long (yearly) timescales. This enabled us to isolate potential residual wobbles in the motion of component B attributable to an orbiting moon.Results. Our analysis reveals tentative astrometric residuals in the HD 206893 B orbit. If interpreted as an exomoon signature, these residuals correspond to a candidate (HD 206893 B I) with an orbital period of approximately 0.76 years and a mass of ~0.4 Jupiter masses. However, the origin of these residuals remains ambiguous and could be due to systematics. Complementing the astrometry, our analysis of GRAVITY R = 4000 spectroscopy for HD 206893 B confirms a clear detection of water, but no CO was found using cross-correlation. We also found that AF Lep b, and β Pic b are the best short-term candidates to look for moons with GRAVITY+.Conclusions. Our observations demonstrate the transformative potential of high-precision astrometry in the search for exomoons and proves the feasibility of the technique to detect moons with masses lower than Jupiter and potentially down to less than Neptune in optimistic cases. Crucially, further high-precision astrometric observations with VLTI/GRAVITY are essential to verify the reality and nature of this signal and apply this technique to a range of planetary systems.
{"title":"Exomoon search with VLTI/GRAVITY around the substellar companion HD 206893 B","authors":"Q. Kral, J. Wang, J. Kammerer, S. Lacour, M. Malin, T. Winterhalder, B. Charnay, C. Perrot, P. Huet, R. Abuter, A. Amorim, W. O. Balmer, M. Benisty, J.-P. Berger, H. Beust, S. Blunt, A. Boccaletti, M. Bonnefoy, H. Bonnet, M. S. Bordoni, G. Bourdarot, W. Brandner, F. Cantalloube, P. Caselli, G. Chauvin, A. Chavez, A. Chomez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Davies, R. Dembet, J. Dexter, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, N. M. Förster Schreiber, P. Garcia, R. Garcia Lopez, T. Gardner, E. Gendron, R. Genzel, S. Gillessen, J. H. Girard, S. Grant, X. Haubois, Th. Henning, S. Hinkley, S. Hippler, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, P. Kervella, L. Kreidberg, N. T. Kurtovic, A.-M. Lagrange, V. Lapeyrère, J.-B. Le Bouquin, D. Lutz, A.-L. Maire, F. Mang, G.-D. Marleau, A. Mérand, P. Mollière, J. D. Monnier, C. Mordasini, D. Mouillet, E. Nasedkin, M. Nowak, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, N. Pourré, L. Pueyo, D. C. Ribeiro, E. Rickman, Z. Rustamkulov, J. Shangguan, T. Shimizu, D. Sing, J. Stadler, T. Stolker, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, A. Vigan, F. Vincent, S. D. von Fellenberg, F. Widmann, J. Woillez, S. Yazici, K. Abd El Dayem, N. Aimar, A. Berdeu, C. Correia, D. Defrère, M. Fabricius, H. Feuchtgruber, A. Foschi, S. F. Hönig, S. Joharle, R. Laugier, O. Lai, J. Leftley, B. Lopez, F. Millour, M. Montargès, N. Morujão, H. Nowacki, J. Osorno, R. Petrov, P. O. Petrucci, S. Rabien, S. Robbe-Dubois, M. Sadun Bordoni, J. Sánchez Bermúdez, D. Santos, J. Sauter, J. Scigliuto, F. Soulez, M. Subroweit, C. Sykes","doi":"10.1051/0004-6361/202557127","DOIUrl":"https://doi.org/10.1051/0004-6361/202557127","url":null,"abstract":"<i>Context<i/>. This study presents the first application of high-precision astrometry to search for exomoons around substellar companions, as this field remains largely unexplored.<i>Aims<i/>. We investigate whether the orbital motion of the companion HD 206893 B exhibits astrometric residuals consistent with the gravitational influence of an exomoon or binary planet.<i>Methods<i/>. Using the VLTI/GRAVITY instrument, we monitored the astrometric positions of HD 206893 B and c on short (days to months) and long (yearly) timescales. This enabled us to isolate potential residual wobbles in the motion of component B attributable to an orbiting moon.<i>Results<i/>. Our analysis reveals tentative astrometric residuals in the HD 206893 B orbit. If interpreted as an exomoon signature, these residuals correspond to a candidate (HD 206893 B I) with an orbital period of approximately 0.76 years and a mass of ~0.4 Jupiter masses. However, the origin of these residuals remains ambiguous and could be due to systematics. Complementing the astrometry, our analysis of GRAVITY <i>R<i/> = 4000 spectroscopy for HD 206893 B confirms a clear detection of water, but no CO was found using cross-correlation. We also found that AF Lep b, and <i>β<i/> Pic b are the best short-term candidates to look for moons with GRAVITY+.<i>Conclusions<i/>. Our observations demonstrate the transformative potential of high-precision astrometry in the search for exomoons and proves the feasibility of the technique to detect moons with masses lower than Jupiter and potentially down to less than Neptune in optimistic cases. Crucially, further high-precision astrometric observations with VLTI/GRAVITY are essential to verify the reality and nature of this signal and apply this technique to a range of planetary systems.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1051/0004-6361/202558046
I. A. Zinchenko, J. M. Vílchez, C. Kehrig, P. Papaderos, J. E. Méndez-Delgado
We present new precise measurements of the electron temperatures and oxygen abundances in the southeast knot of I Zw 18, one of the most metal poor blue compact dwarf galaxies known. We used spectroscopic data from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1). For the first time in I Zw 18, we directly measured the electron temperature in the low-ionization zone using the rarely detected [O II]λλ7320,7330 doublet. We also detected the [O III]λ4363 and [S III]λ6312 auroral lines, which are associated with high- and intermediate-ionization zones, respectively. We derived Te([O III]) = 21 200 ± 860 K, Te([O II]) = 16 170 ± 950 K, and Te([S III]) = 17 290±1750, which highlights a significant temperature difference between the ionization zones. Using these direct temperature measurements, we determined a total oxygen abundance of 12+log(O/H) = 7.066 ± 0.046, log(N/O) = –1.509 ± 0.097, and log(S/O) = –1.558 ± 0.041. Our results extend the calibration of t2 − t3 relations to the highest temperatures and provide important anchor points for the temperature structure of extremely metal-poor H II regions, including high-redshift galaxies, for which direct temperature measurements are especially challenging.
{"title":"First direct electron temperature measurement in [O II] zone in I Zw 18","authors":"I. A. Zinchenko, J. M. Vílchez, C. Kehrig, P. Papaderos, J. E. Méndez-Delgado","doi":"10.1051/0004-6361/202558046","DOIUrl":"https://doi.org/10.1051/0004-6361/202558046","url":null,"abstract":"We present new precise measurements of the electron temperatures and oxygen abundances in the southeast knot of I Zw 18, one of the most metal poor blue compact dwarf galaxies known. We used spectroscopic data from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1). For the first time in I Zw 18, we directly measured the electron temperature in the low-ionization zone using the rarely detected [O II]<i>λλ<i/>7320,7330 doublet. We also detected the [O III]<i>λ<i/>4363 and [S III]<i>λ<i/>6312 auroral lines, which are associated with high- and intermediate-ionization zones, respectively. We derived T<sub><i>e<i/><sub/>([O III]) = 21 200 ± 860 K, T<sub><i>e<i/><sub/>([O II]) = 16 170 ± 950 K, and T<sub><i>e<i/><sub/>([S III]) = 17 290±1750, which highlights a significant temperature difference between the ionization zones. Using these direct temperature measurements, we determined a total oxygen abundance of 12+log(O/H) = 7.066 ± 0.046, log(N/O) = –1.509 ± 0.097, and log(S/O) = –1.558 ± 0.041. Our results extend the calibration of <i>t<i/><sub>2<sub/> − <i>t<i/><sub>3<sub/> relations to the highest temperatures and provide important anchor points for the temperature structure of extremely metal-poor H II regions, including high-redshift galaxies, for which direct temperature measurements are especially challenging.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"43 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1051/0004-6361/202555798
M. Archipley, A. Hryciuk, L. E. Bleem, K. Kornoelje, M. Klein, A. J. Anderson, B. Ansarinejad, M. Aravena, L. Balkenhol, P. S. Barry, K. Benabed, A. N. Bender, B. A. Benson, F. Bianchini, S. Bocquet, F. R. Bouchet, E. Camphuis, M. G. Campitiello, J. E. Carlstrom, J. Cathey, C. L. Chang, S. C. Chapman, P. Chaubal, P. M. Chichura, A. Chokshi, T.-L. Chou, A. Coerver, T. M. Crawford, C. Daley, T. de Haan, R. P. Deane, K. R. Dibert, M. A. Dobbs, M. Doohan, A. Doussot, D. Dutcher, W. Everett, C. Feng, K. R. Ferguson, K. Fichman, B. Floyd, A. Foster, S. Galli, A. E. Gambrel, R. W. Gardner, F. Ge, N. Goeckner-Wald, A. Gonzalez, S. Grandis, T. R. Greve, R. Gualtieri, F. Guidi, S. Guns, N. W. Halverson, R. Hill, E. Hivon, G. P. Holder, W. L. Holzapfel, J. C. Hood, N. Huang, F. Kéruzoré, A. R. Khalife, L. Knox, M. Korman, C.-L. Kuo, K. Levy, A. E. Lowitz, C. Lu, G. P. Lynch, A. Maniyar, E. S. Martsen, F. Menanteau, M. Millea, J. Montgomery, Y. Nakato, T. Natoli, G. I. Noble, Y. Omori, A. Ouellette, Z. Pan, K. A. Phadke, A. W. Pollak, K. Prabhu, W. Quan, S. Raghunathan, M. Rahimi, A. Rahlin, C. L. Reichardt, C. Reuter, M. Rouble, J. E. Ruhl, E. Schiappucci, A. Simpson, J. A. Sobrin, B. Stalder, A. A. Stark, N. Sulzenauer, C. Tandoi, B. Thorne, C. Trendafilova, C. Umilta, J. D. Vieira, A. Vitrier, D. Vizgan, Y. Wan, A. Weiß, N. Whitehorn, W. L. K. Wu, M. R. Young, J. A. Zebrowski, D. Zhou
Context. The South Pole Telescope third-generation camera (SPT-3G) has observed over 10 000 square degrees of sky at 95, 150, and 220 GHz (3.3, 2.0, 1.4 mm, respectively) and will significantly overlap the ongoing 14 000 square-degree Euclid Wide Survey. The Euclid collaboration recently released Euclid Deep Field South (EDF-S) observations of 23 square degrees at wide field depths in the first quick data release (Q1).Aims. With the goal of releasing complementary millimeter-wave data and encouraging legacy science, we performed dedicated observations of a 57-square-degree field overlapping the EDF-S.Methods. The observing time totaled 20 days, and we reached noise depths of 4.3, 3.8, and 13.2 μK-arcmin at 95, 150, and 220 GHz, respectively.Results. In this work we present the temperature maps and two catalogs constructed from these data. The emissive source catalog contains 601 objects (334 inside EDF-S) with 54% synchrotron-dominated sources and 46% thermal dust emission-dominated sources. The 5σ detection thresholds are 1.7, 2.0, and 6.5 mJy in the three bands. The cluster catalog contains 217 cluster candidates (121 inside EDF-S) with median mass M500c = 2.12 × 1014M⊙/h70 and median redshift z = 0.70, corresponding to an order-of-magnitude improvement in cluster density over previous tSZ-selected catalogs in this region (3.81 clusters per square degree).Conclusions. The overlap between SPT and Euclid data will enable a range of multiwavelength studies of the aforementioned source populations. This work serves as the first step toward joint projects between SPT and Euclid and provides a rich dataset containing information on galaxies, clusters, and their environments.
{"title":"Millimeter-wave observations of Euclid Deep Field South using the South Pole Telescope","authors":"M. Archipley, A. Hryciuk, L. E. Bleem, K. Kornoelje, M. Klein, A. J. Anderson, B. Ansarinejad, M. Aravena, L. Balkenhol, P. S. Barry, K. Benabed, A. N. Bender, B. A. Benson, F. Bianchini, S. Bocquet, F. R. Bouchet, E. Camphuis, M. G. Campitiello, J. E. Carlstrom, J. Cathey, C. L. Chang, S. C. Chapman, P. Chaubal, P. M. Chichura, A. Chokshi, T.-L. Chou, A. Coerver, T. M. Crawford, C. Daley, T. de Haan, R. P. Deane, K. R. Dibert, M. A. Dobbs, M. Doohan, A. Doussot, D. Dutcher, W. Everett, C. Feng, K. R. Ferguson, K. Fichman, B. Floyd, A. Foster, S. Galli, A. E. Gambrel, R. W. Gardner, F. Ge, N. Goeckner-Wald, A. Gonzalez, S. Grandis, T. R. Greve, R. Gualtieri, F. Guidi, S. Guns, N. W. Halverson, R. Hill, E. Hivon, G. P. Holder, W. L. Holzapfel, J. C. Hood, N. Huang, F. Kéruzoré, A. R. Khalife, L. Knox, M. Korman, C.-L. Kuo, K. Levy, A. E. Lowitz, C. Lu, G. P. Lynch, A. Maniyar, E. S. Martsen, F. Menanteau, M. Millea, J. Montgomery, Y. Nakato, T. Natoli, G. I. Noble, Y. Omori, A. Ouellette, Z. Pan, K. A. Phadke, A. W. Pollak, K. Prabhu, W. Quan, S. Raghunathan, M. Rahimi, A. Rahlin, C. L. Reichardt, C. Reuter, M. Rouble, J. E. Ruhl, E. Schiappucci, A. Simpson, J. A. Sobrin, B. Stalder, A. A. Stark, N. Sulzenauer, C. Tandoi, B. Thorne, C. Trendafilova, C. Umilta, J. D. Vieira, A. Vitrier, D. Vizgan, Y. Wan, A. Weiß, N. Whitehorn, W. L. K. Wu, M. R. Young, J. A. Zebrowski, D. Zhou","doi":"10.1051/0004-6361/202555798","DOIUrl":"https://doi.org/10.1051/0004-6361/202555798","url":null,"abstract":"<i>Context<i/>. The South Pole Telescope third-generation camera (SPT-3G) has observed over 10 000 square degrees of sky at 95, 150, and 220 GHz (3.3, 2.0, 1.4 mm, respectively) and will significantly overlap the ongoing 14 000 square-degree <i>Euclid<i/> Wide Survey. The <i>Euclid<i/> collaboration recently released <i>Euclid<i/> Deep Field South (EDF-S) observations of 23 square degrees at wide field depths in the first quick data release (Q1).<i>Aims<i/>. With the goal of releasing complementary millimeter-wave data and encouraging legacy science, we performed dedicated observations of a 57-square-degree field overlapping the EDF-S.<i>Methods<i/>. The observing time totaled 20 days, and we reached noise depths of 4.3, 3.8, and 13.2 μK-arcmin at 95, 150, and 220 GHz, respectively.<i>Results<i/>. In this work we present the temperature maps and two catalogs constructed from these data. The emissive source catalog contains 601 objects (334 inside EDF-S) with 54% synchrotron-dominated sources and 46% thermal dust emission-dominated sources. The 5σ detection thresholds are 1.7, 2.0, and 6.5 mJy in the three bands. The cluster catalog contains 217 cluster candidates (121 inside EDF-S) with median mass <i>M<i/><sub>500c<sub/> = 2.12 × 10<sup>14<sup/> <i>M<i/><sub>⊙<sub/><i>/h<i/><sub>70<sub/> and median redshift <i>z<i/> = 0.70, corresponding to an order-of-magnitude improvement in cluster density over previous tSZ-selected catalogs in this region (3.81 clusters per square degree).<i>Conclusions<i/>. The overlap between SPT and <i>Euclid<i/> data will enable a range of multiwavelength studies of the aforementioned source populations. This work serves as the first step toward joint projects between SPT and <i>Euclid<i/> and provides a rich dataset containing information on galaxies, clusters, and their environments.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"281 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1051/0004-6361/202558345
B. Mosser, M. Takata, C. Pinçon, M. S. Cunha, M. Vrard, K. Belkacem, S. Deheuvels, M. Matteuzzi
Context. Dipole mixed modes observed in the oscillation pattern of red giant stars probe the radiative regions in the stellar core.Aims. Oscillation spectra of helium-core-burning stars sometimes show extra peaks that remain unexplained by the dipole mixed-mode pattern expected from the coupling of a radiative cavity in the stellar core and a pressure cavity in the stellar envelope.Methods. We use the asymptotic expansion developed for a multi-cavity star in order to characterize these extra peaks.Results. The analytical resonance condition of the multi-cavity gravito-acoustic modes, with two inner gravity cavities and an outer pressure cavity, helps us explain that the apparent extra peaks are dipole mixed modes that follow the three-cavity oscillation pattern. The derivation of the two asymptotic period spacings associated with the two distinct regions in the radiative core provides an estimate of the full radiative cavity.Conclusions. Our results provide new constraints for analyzing the overshoot or mixing in the core of helium-core-burning stars. An important structure discontinuity inside the radiative core may explain the larger than expected observed period spacings.
{"title":"Extra modes in helium-core-burning stars probing an infra core cavity","authors":"B. Mosser, M. Takata, C. Pinçon, M. S. Cunha, M. Vrard, K. Belkacem, S. Deheuvels, M. Matteuzzi","doi":"10.1051/0004-6361/202558345","DOIUrl":"https://doi.org/10.1051/0004-6361/202558345","url":null,"abstract":"<i>Context.<i/> Dipole mixed modes observed in the oscillation pattern of red giant stars probe the radiative regions in the stellar core.<i>Aims.<i/> Oscillation spectra of helium-core-burning stars sometimes show extra peaks that remain unexplained by the dipole mixed-mode pattern expected from the coupling of a radiative cavity in the stellar core and a pressure cavity in the stellar envelope.<i>Methods.<i/> We use the asymptotic expansion developed for a multi-cavity star in order to characterize these extra peaks.<i>Results.<i/> The analytical resonance condition of the multi-cavity gravito-acoustic modes, with two inner gravity cavities and an outer pressure cavity, helps us explain that the apparent extra peaks are dipole mixed modes that follow the three-cavity oscillation pattern. The derivation of the two asymptotic period spacings associated with the two distinct regions in the radiative core provides an estimate of the full radiative cavity.<i>Conclusions.<i/> Our results provide new constraints for analyzing the overshoot or mixing in the core of helium-core-burning stars. An important structure discontinuity inside the radiative core may explain the larger than expected observed period spacings.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"8 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1051/0004-6361/202556814
A. Crespo Gómez, L. Colina, P. G. Pérez-González, J. Álvarez-Márquez, M. García-Marín, A. Alonso-Herrero, M. Annunziatella, A. Bik, S. Bosman, A. J. Bunker, A. Labiano, D. Langeroodi, P. Rinaldi, G. Östlin, L. Boogaard, S. Gillman, G. Barro, S. L. Finkelstein, G. C. K. Leung
We present new MIRI F560W, F770W, and F1000W imaging of the galaxy GN-z11 at a redshift of 10.603. We report a significant detection (14σ) in the F560W and F770W images, and a marginal detection (3.2σ) in the F1000W filter. The new MIRI observations cover the optical-red spectral range and significantly extend previous NIRCam wavelength coverage from rest-frame 0.38 μm up to 0.86 μm. In this work, we analyse the spectral energy distribution (SED) combining this new MIRI imaging data with archival NIRSpec/Prism and MRS spectroscopy, and NIRCam imaging, i.e. covering the rest-frame 0.12–0.86 μm. New constraints such as the equivalent widths of the strong optical lines ([O III]λ5008, Hβ and Hα) and the continuum emission at rest-frame 0.48 μm, 0.66 μm, and 0.86 μm, free of emission line contributions, are presented. The continuum emission shows a flat energy distribution, in fν, up to 0.5 μm, compatible with the presence of a mixed stellar population of young (4 ± 1 Myr) and mature (63 ± 23 Myr) stars that also account for the [O III], Hβ, and Hα emission lines. The continuum at rest-frame 0.66 μm shows a 36 ± 3% flux excess above the predicted flux for a mixed stellar population, pointing to the presence of an additional source contributing at these wavelengths. This excess increases to 91 ± 28% at rest-frame 0.86 μm, although with a large uncertainty due to the marginal detection in the F1000W filter. We consider that hot dust emission in the dusty torus around a type 2 active galactic nucleus (AGN) could be responsible for the observed excess. Alternatively, this excess could be due to hot dust emission or a photoluminiscence dust process (Extended Red Emission, ERE) under the extreme UV radiation field, as is observed in local metal-poor galaxies and in young compact starbursts. The presence of a type 1 AGN is not supported by the observed SED as the hot dust emission in luminous high-z quasi-stellar objects (QSOs) contributes at wavelengths above rest-frame 1 μm, and an additional ad hoc red source would be required to explain the observed flux excess at 0.66 and 0.86 μm. Additional deep MIRI imaging covering the rest-frame near-IR is needed to confirm the flux detection at 10 μm, and to discriminate between the different hot dust emission in the extreme starburst and AGN scenarios.
{"title":"MIRI spectrophotometry of GN-z11: Detection and nature of an optical red continuum component","authors":"A. Crespo Gómez, L. Colina, P. G. Pérez-González, J. Álvarez-Márquez, M. García-Marín, A. Alonso-Herrero, M. Annunziatella, A. Bik, S. Bosman, A. J. Bunker, A. Labiano, D. Langeroodi, P. Rinaldi, G. Östlin, L. Boogaard, S. Gillman, G. Barro, S. L. Finkelstein, G. C. K. Leung","doi":"10.1051/0004-6361/202556814","DOIUrl":"https://doi.org/10.1051/0004-6361/202556814","url":null,"abstract":"We present new MIRI F560W, F770W, and F1000W imaging of the galaxy GN-z11 at a redshift of 10.603. We report a significant detection (14<i>σ<i/>) in the F560W and F770W images, and a marginal detection (3.2<i>σ<i/>) in the F1000W filter. The new MIRI observations cover the optical-red spectral range and significantly extend previous NIRCam wavelength coverage from rest-frame 0.38 μm up to 0.86 μm. In this work, we analyse the spectral energy distribution (SED) combining this new MIRI imaging data with archival NIRSpec/Prism and MRS spectroscopy, and NIRCam imaging, i.e. covering the rest-frame 0.12–0.86 μm. New constraints such as the equivalent widths of the strong optical lines ([O III]<i>λ<i/>5008, H<i>β<i/> and H<i>α<i/>) and the continuum emission at rest-frame 0.48 μm, 0.66 μm, and 0.86 μm, free of emission line contributions, are presented. The continuum emission shows a flat energy distribution, in <i>f<i/><sub><i>ν<i/><sub/>, up to 0.5 μm, compatible with the presence of a mixed stellar population of young (4 ± 1 Myr) and mature (63 ± 23 Myr) stars that also account for the [O III], H<i>β<i/>, and H<i>α<i/> emission lines. The continuum at rest-frame 0.66 μm shows a 36 ± 3% flux excess above the predicted flux for a mixed stellar population, pointing to the presence of an additional source contributing at these wavelengths. This excess increases to 91 ± 28% at rest-frame 0.86 μm, although with a large uncertainty due to the marginal detection in the F1000W filter. We consider that hot dust emission in the dusty torus around a type 2 active galactic nucleus (AGN) could be responsible for the observed excess. Alternatively, this excess could be due to hot dust emission or a photoluminiscence dust process (Extended Red Emission, ERE) under the extreme UV radiation field, as is observed in local metal-poor galaxies and in young compact starbursts. The presence of a type 1 AGN is not supported by the observed SED as the hot dust emission in luminous high-<i>z<i/> quasi-stellar objects (QSOs) contributes at wavelengths above rest-frame 1 μm, and an additional ad hoc red source would be required to explain the observed flux excess at 0.66 and 0.86 μm. Additional deep MIRI imaging covering the rest-frame near-IR is needed to confirm the flux detection at 10 μm, and to discriminate between the different hot dust emission in the extreme starburst and AGN scenarios.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"74 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1051/0004-6361/202557986
Z. Roumeliotis, L. Matrà, G. M. Kennedy, S. Marino, K. Y. L. Su, D. J. Wilner, M. C. Wyatt, A. P. Jackson
Context. Giant impacts between planetary embryos are a natural step in the terrestrial planet formation process and are expected to create disks of warm debris in the terrestrial regions of their stars. Understanding the gas and dust debris produced in giant impacts is vital for comprehending and constraining models of planetary collisions.Aims. We reveal the distribution of millimeter (mm) grains in the giant impact debris disk of HD 172555 for the first time, using new ALMA 0.87 mm observations at ∼80 mas (2.3 au) resolution.Methods. We modeled the interferometric visibilities to obtain basic spatial properties of the disk and compared these data to the disk’s dust and gas distributions at other wavelengths.Results. We detected the star and dust emission from an inclined disk out to ∼9 au and down to 2.3 au (on-sky) from the central star, with no significant asymmetry in the dust distribution. The radiative transfer modeling of the visibilities indicates the disk surface density distribution of mm grains most likely peaks around ∼5 au, while the width inferred remains model-dependent at the S/N of the data. We highlighted an outward radial offset of the small grains traced by scattered light observations compared to the mm grains, which could be explained by the combined effect of gas drag and radiation pressure in the presence of large enough gas densities. Furthermore, our SED modeling implies a size distribution slope for the mm grains consistent with the expectation of collisional evolution and flatter than inferred for the micron-sized grains, implying a break in the grain size distribution and confirming an overabundance of small grains.
{"title":"Resolving the terrestrial planet-forming region of HD 172555 with ALMA","authors":"Z. Roumeliotis, L. Matrà, G. M. Kennedy, S. Marino, K. Y. L. Su, D. J. Wilner, M. C. Wyatt, A. P. Jackson","doi":"10.1051/0004-6361/202557986","DOIUrl":"https://doi.org/10.1051/0004-6361/202557986","url":null,"abstract":"<i>Context<i/>. Giant impacts between planetary embryos are a natural step in the terrestrial planet formation process and are expected to create disks of warm debris in the terrestrial regions of their stars. Understanding the gas and dust debris produced in giant impacts is vital for comprehending and constraining models of planetary collisions.<i>Aims<i/>. We reveal the distribution of millimeter (mm) grains in the giant impact debris disk of HD 172555 for the first time, using new ALMA 0.87 mm observations at ∼80 mas (2.3 au) resolution.<i>Methods<i/>. We modeled the interferometric visibilities to obtain basic spatial properties of the disk and compared these data to the disk’s dust and gas distributions at other wavelengths.<i>Results<i/>. We detected the star and dust emission from an inclined disk out to ∼9 au and down to 2.3 au (on-sky) from the central star, with no significant asymmetry in the dust distribution. The radiative transfer modeling of the visibilities indicates the disk surface density distribution of mm grains most likely peaks around ∼5 au, while the width inferred remains model-dependent at the S/N of the data. We highlighted an outward radial offset of the small grains traced by scattered light observations compared to the mm grains, which could be explained by the combined effect of gas drag and radiation pressure in the presence of large enough gas densities. Furthermore, our SED modeling implies a size distribution slope for the mm grains consistent with the expectation of collisional evolution and flatter than inferred for the micron-sized grains, implying a break in the grain size distribution and confirming an overabundance of small grains.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"120 8 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146070548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1051/0004-6361/202557949
F. Mattig, B. N. Barlow, D. Liu, M. Dorsch, S. Geier, M. Pritzkuleit, H. Dawson, B. Wang, V. Schaffenroth, T. Kupfer, C. Derbyshire, S. Barocci-Faul
Context. Massive short-period binaries involving hot subdwarf stars (sdO/Bs) are rare but very relevant to constraining pathways for binary star evolution. Moreover, some of the most promising candidate progenitor systems leading to Type Ia supernovae (SNe Ia) involve sdO/Bs. LAMOST J065816.72+094343.1 has been identified to be such a candidate system.Aims. To explore the nature and evolutionary future of LAMOST J065816.72+094343.1, we complemented archival spectroscopic data with additional time series spectra as well as high-resolution spectroscopy of the object. After combining these with photometric data, we determined the orbital parameters of the system and the mass of the companion.Methods. We solved the orbit of the system by analyzing 68 low- and medium-resolution spectra using state-of-the-art mixed local thermodynamic equilibrium (LTE) and non-LTE model atmospheres. Additionally, we gathered nine high-resolution spectra to determine atmospheric parameters and the projected rotational velocity of the sdOB. The inclination angle of the system was constrained assuming tidal synchronization of the sdOB, which was verified via analysis of the ellipsoidal variations in the TESS light curve.Results. We determine LAMOST J065816.72+094343.1 to be a binary consisting of a massive 0.82 ± 0.17 M⊙ sdOB component with a unseen companion. Due to the companion’s mass being very close to the Chandrasekhar mass limit and high for a white dwarf, it is unclear whether the compact companion is a white dwarf or a neutron star. We find the system to be in a close orbit, with a period of P = 0.31955193 d and an inclination angle of . While the exact nature of the companion remains unknown, we determine the system to either lead to a SN Ia or an intermediate mass binary pulsar, potentially after a phase as an intermediate-mass X-ray binary.
{"title":"The massive hot subdwarf binary LAMOST J065816.72+094343.1","authors":"F. Mattig, B. N. Barlow, D. Liu, M. Dorsch, S. Geier, M. Pritzkuleit, H. Dawson, B. Wang, V. Schaffenroth, T. Kupfer, C. Derbyshire, S. Barocci-Faul","doi":"10.1051/0004-6361/202557949","DOIUrl":"https://doi.org/10.1051/0004-6361/202557949","url":null,"abstract":"<i>Context.<i/> Massive short-period binaries involving hot subdwarf stars (sdO/Bs) are rare but very relevant to constraining pathways for binary star evolution. Moreover, some of the most promising candidate progenitor systems leading to Type Ia supernovae (SNe Ia) involve sdO/Bs. LAMOST J065816.72+094343.1 has been identified to be such a candidate system.<i>Aims.<i/> To explore the nature and evolutionary future of LAMOST J065816.72+094343.1, we complemented archival spectroscopic data with additional time series spectra as well as high-resolution spectroscopy of the object. After combining these with photometric data, we determined the orbital parameters of the system and the mass of the companion.<i>Methods.<i/> We solved the orbit of the system by analyzing 68 low- and medium-resolution spectra using state-of-the-art mixed local thermodynamic equilibrium (LTE) and non-LTE model atmospheres. Additionally, we gathered nine high-resolution spectra to determine atmospheric parameters and the projected rotational velocity of the sdOB. The inclination angle of the system was constrained assuming tidal synchronization of the sdOB, which was verified via analysis of the ellipsoidal variations in the TESS light curve.<i>Results.<i/> We determine LAMOST J065816.72+094343.1 to be a binary consisting of a massive 0.82 ± 0.17 M<sub>⊙<sub/> sdOB component with a unseen companion. Due to the companion’s mass being very close to the Chandrasekhar mass limit and high for a white dwarf, it is unclear whether the compact companion is a white dwarf or a neutron star. We find the system to be in a close orbit, with a period of <i>P<i/> = 0.31955193 d and an inclination angle of . While the exact nature of the companion remains unknown, we determine the system to either lead to a SN Ia or an intermediate mass binary pulsar, potentially after a phase as an intermediate-mass X-ray binary.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1051/0004-6361/202558202
M. M. Bennedik, B. Stelzer, H. Isaacson, A. Binks, M. Caramazza, F. Haberl
As the only known unambiguous star in a Maunder minimum-like chromospheric activity state, the properties of HD 166620 can provide valuable insight into the behaviour of the Sun during the historic extended low-states of its activity cycle. The coronal X-ray activity of HD 166620 has so far only been probed with a ROSAT/HRI observation in 1996, near the chromospheric activity maximum before the star entered its grand minimum around 2004. We conducted a deep XMM-Newton observation of HD 166620 during its chromospheric Ca II H&K activity grand minimum to achieve a better understanding of its magnetic activity. We detected HD 166620 with an X-ray luminosity of , corresponding to and an X-ray surface flux of . With respect to the earlier ROSAT observation, the X-ray brightness of HD 166620 has decreased by a factor of 2.5 during its Maunder minimum-like state. To place its X-ray properties into context, we constructed an X-ray sample of late-type stars within 10 pc of the Sun. The activity of HD 166620 is below the levels of all other K dwarfs in the 10 pc sample. The corona of HD 166620 during its grand minimum emits at the level of the solar background corona, which implies that it has no large active magnetic structures. Along with long-term Ca II H&K monitoring of HD 166620, this result provides evidence that the solar activity during the Maunder minimum was not reduced significantly below the levels seen during its present-day cycle minima. The similar X-ray surface flux of HD 166620 and the modern quiet Sun, and also their Rossby number near the critical value of spin-down models, suggest a connection between the regime of weakened magnetic braking and the occurrence of Maunder minimum states.
HD 166620是目前已知唯一一颗处于类似蒙德极小期色球活动状态的明确恒星，它的特性可以为了解太阳在历史上延长的低活动周期中的行为提供有价值的见解。到目前为止，HD 166620的日冕x射线活动仅在1996年通过ROSAT/HRI观测进行了探测，在2004年左右进入最小值之前，接近色球活动的最大值。我们在hd166620的色球Ca II H&K活动极小期对其进行了深入的xmm -牛顿观测，以更好地了解其磁活动。我们探测到HD 166620的x射线光度为，对应的x射线表面通量为。相对于早期的ROSAT观测，HD 166620的x射线亮度在其蒙德最小值状态期间下降了2.5倍。为了了解它的x射线特性，我们在距离太阳10%的范围内构建了一个晚期恒星的x射线样本。HD 166620的活动水平低于10%样本中所有其他K矮星的水平。HD 166620在其极小期的日冕辐射水平相当于太阳背景日冕，这意味着它没有大型的活动磁结构。结合对hd166620的长期Ca II H&K监测，这一结果提供了证据，证明蒙德极小期的太阳活动并没有明显减少到低于当前周期极小期的水平。HD 166620的x射线表面通量与现代安静太阳相似，而且它们的罗斯比数接近自旋下降模型的临界值，这表明磁制动减弱的状态与蒙德最小状态的发生之间存在联系。
{"title":"Quiet, but not silent","authors":"M. M. Bennedik, B. Stelzer, H. Isaacson, A. Binks, M. Caramazza, F. Haberl","doi":"10.1051/0004-6361/202558202","DOIUrl":"https://doi.org/10.1051/0004-6361/202558202","url":null,"abstract":"As the only known unambiguous star in a Maunder minimum-like chromospheric activity state, the properties of HD 166620 can provide valuable insight into the behaviour of the Sun during the historic extended low-states of its activity cycle. The coronal X-ray activity of HD 166620 has so far only been probed with a ROSAT/HRI observation in 1996, near the chromospheric activity maximum before the star entered its grand minimum around 2004. We conducted a deep <i>XMM-Newton<i/> observation of HD 166620 during its chromospheric Ca II H&K activity grand minimum to achieve a better understanding of its magnetic activity. We detected HD 166620 with an X-ray luminosity of , corresponding to and an X-ray surface flux of . With respect to the earlier ROSAT observation, the X-ray brightness of HD 166620 has decreased by a factor of 2.5 during its Maunder minimum-like state. To place its X-ray properties into context, we constructed an X-ray sample of late-type stars within 10 pc of the Sun. The activity of HD 166620 is below the levels of all other K dwarfs in the 10 pc sample. The corona of HD 166620 during its grand minimum emits at the level of the solar background corona, which implies that it has no large active magnetic structures. Along with long-term Ca II H&K monitoring of HD 166620, this result provides evidence that the solar activity during the Maunder minimum was not reduced significantly below the levels seen during its present-day cycle minima. The similar X-ray surface flux of HD 166620 and the modern quiet Sun, and also their Rossby number near the critical value of spin-down models, suggest a connection between the regime of weakened magnetic braking and the occurrence of Maunder minimum states.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"30 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1051/0004-6361/202558298
J. Drevon, C. Paladini, S. Höfner, L. Planquart, L. Siess, A. Jorissen, M. Montargés, W. Vlemmings, T. Khouri, H. Olofsson, J. Alonso-Hernandez, E. De Beck, J. P. Fonfria, J. Hron, A. Matter, N. Nardetto, K. Ohnaka, C. Sanchez-Contreras, G. Weigelt, M. Wittkowski, B. Bojnordi Arbab, B. Aringer, F. Baron, A. Chiavassa, P. Cruzalébes, W. C. Danchi, F. Kerschbaum, J. Leftley, E. Lagadec, B. Lopez, F. Lykou, F. Millour, G. Rau, J. Sanchez-Bermudez, F. Thévenin, S. Van Eck, L. Velilla-Prieto
Aims. We investigate how the presence of a binary companion appears to affect dust and molecule formation in the circumstellar environment of a star on the asymptotic giant branch (AGB).Methods.L- and N-band observations obtained over the course of one month with the multi aperTure mid-infrared spectroScopic experiment instrument (MATISSE) at the very large telescope interferometer (VLTI) were used to constrain the distribution of dust and molecules in the close environment of π1 Gru through image reconstruction. The reconstructed images were fit to the interferometric observables, that is, the visibilities and closure phases, using the two Python-based tools Python for MiRA (PYRA) and mean astrophysical images with PYRA (MYTHRA) built around the multi-aperture image reconstruction algorithm (MiRA).Results. Our observations support (i) a wind Roche-lobe overflow (WRLOF) scenario, where mass transfer from the AGB star to its companion produces a possible circumcompanion disk in the L band around π1 Gru C, with a central cavity that likely traces dust sublimation and a circumcompanion envelope in the N band. (ii) A main-sequence nature for the companion: Because both Atacama large millimeter/submillimeter array (ALMA) and the VLTI/MATISSE N-band observations show emission, we favor a thermal infrared emission from the main-sequence star over free-free emission from a with dwarf companion. Finally, (iii) a plume-like structure extending from π1 Gru C, likely marking the onset of the spiral observed at larger scales. Together, this provides direct evidence that links small-scale mass transfer and disk formation through WRLOF to the global circumstellar morphology.Conclusions. These results highlight the atmospheric deformation induced by the companion, reveal ongoing mass transfer between the evolved star and its companion, and indicate a circumcompanion disk-like structure.
目标。我们研究了双星伴星的存在如何影响渐近巨支（AGB）上恒星的星周环境中的尘埃和分子形成。利用甚大望远镜干涉仪（VLTI）上的多孔径中红外光谱实验仪（MATISSE）近一个月的L波段和n波段观测数据，通过图像重建来约束π1 Gru近距离环境中尘埃和分子的分布。利用基于Python的工具Python for MiRA （PYRA）和基于多孔径图像重建算法（MiRA）构建的带有PYRA的天体物理平均图像（MYTHRA），将重建图像与干涉观测值即可见性和闭合相位进行拟合。我们的观测结果支持(1)风罗氏叶溢出（WRLOF）假说，即质量从AGB恒星转移到它的伴星，在π1 Gru C周围的L波段产生一个可能的环伴盘，其中心空腔可能是尘埃升华的轨迹，在N波段有一个环伴包络。（ii）伴星的主序星性质：由于阿塔卡马大型毫米/亚毫米阵列（ALMA）和VLTI/MATISSE n波段观测都显示了辐射，我们更倾向于主序星的热红外辐射，而不是有矮伴星的自由-自由辐射。最后，（iii）从π1 Gru C延伸的羽状结构，可能标志着在更大尺度上观测到的螺旋的开始。总之，这提供了直接的证据，证明通过WRLOF将小规模的质量传递和盘的形成与全球的星周形态联系起来。这些结果突出了伴星引起的大气变形，揭示了演化恒星与其伴星之间持续的质量传递，并表明了一个环绕伴星的盘状结构。
{"title":"Direct imaging of mass transfer and circumcompanion structures in π1 Gru with VLTI/MATISSE","authors":"J. Drevon, C. Paladini, S. Höfner, L. Planquart, L. Siess, A. Jorissen, M. Montargés, W. Vlemmings, T. Khouri, H. Olofsson, J. Alonso-Hernandez, E. De Beck, J. P. Fonfria, J. Hron, A. Matter, N. Nardetto, K. Ohnaka, C. Sanchez-Contreras, G. Weigelt, M. Wittkowski, B. Bojnordi Arbab, B. Aringer, F. Baron, A. Chiavassa, P. Cruzalébes, W. C. Danchi, F. Kerschbaum, J. Leftley, E. Lagadec, B. Lopez, F. Lykou, F. Millour, G. Rau, J. Sanchez-Bermudez, F. Thévenin, S. Van Eck, L. Velilla-Prieto","doi":"10.1051/0004-6361/202558298","DOIUrl":"https://doi.org/10.1051/0004-6361/202558298","url":null,"abstract":"<i>Aims.<i/> We investigate how the presence of a binary companion appears to affect dust and molecule formation in the circumstellar environment of a star on the asymptotic giant branch (AGB).<i>Methods.L<i/>- and <i>N<i/>-band observations obtained over the course of one month with the multi aperTure mid-infrared spectroScopic experiment instrument (MATISSE) at the very large telescope interferometer (VLTI) were used to constrain the distribution of dust and molecules in the close environment of <i>π<i/><sup>1<sup/> Gru through image reconstruction. The reconstructed images were fit to the interferometric observables, that is, the visibilities and closure phases, using the two Python-based tools Python for MiRA (PYRA) and mean astrophysical images with PYRA (MYTHRA) built around the multi-aperture image reconstruction algorithm (MiRA).<i>Results.<i/> Our observations support (i) a wind Roche-lobe overflow (WRLOF) scenario, where mass transfer from the AGB star to its companion produces a possible circumcompanion disk in the <i>L<i/> band around <i>π<i/><sup>1<sup/> Gru C, with a central cavity that likely traces dust sublimation and a circumcompanion envelope in the <i>N<i/> band. (ii) A main-sequence nature for the companion: Because both Atacama large millimeter/submillimeter array (ALMA) and the VLTI/MATISSE <i>N<i/>-band observations show emission, we favor a thermal infrared emission from the main-sequence star over free-free emission from a with dwarf companion. Finally, (iii) a plume-like structure extending from <i>π<i/><sup>1<sup/> Gru C, likely marking the onset of the spiral observed at larger scales. Together, this provides direct evidence that links small-scale mass transfer and disk formation through WRLOF to the global circumstellar morphology.<i>Conclusions.<i/> These results highlight the atmospheric deformation induced by the companion, reveal ongoing mass transfer between the evolved star and its companion, and indicate a circumcompanion disk-like structure.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1051/0004-6361/202557939
V. Karteyeva, R. Nakibov, I. Petrashkevich, M. Medvedev, A. Vasyunin
Context. Only six molecules containing an N-O bond are detected in the gaseous phase of the interstellar medium. One of them is nitrous oxide (N2O), which was unsuccessfully searched for in solid form since the launch of the Infrared Space Observatory (ISO) mission. The observational capabilities of the James Webb Space Telescope (JWST) present the possibility of identifying solid interstellar N2O.Aims. We aim to identify nitrous oxide in open JWST spectra of interstellar ices toward a sample of Class 0, 0/I, and flat protostars using the relevant laboratory mixtures of N2O-bearing interstellar ice analogs.Methods. A set of laboratory infrared transmission spectra was obtained for the following mixtures: N2O:CO2 = 1:20, N2O:CO = 1:20, N2O:N2 = 1:20, N2O:CO2:CO = 1:15:5, and N2O:CO2:N2 = 1:15:13 at 10–23 K. A search for N2O in JWST NIRSpec spectra toward 50 protostars was performed by fitting the 4.44–4.47 μm (2250–2235 cm−1) NN-stretch absorption band with new laboratory mixtures of N2O-bearing ices.Results. We claim the first secure identification of N2O in 16 protostars. The fitting results show that N2O is formed predominantly within the apolar layer of the ice mantles, which are rich in CO, CO2, and N2. The abundance of solid N2O is estimated at 0.2–2.1% relative to solid CO. We present the band strengths for N2O in the mixtures corresponding to the apolar layer. We also report the identification of the C-N stretch band at 4.42 μm (2260 cm−1), which we tentatively assign to HNCO, the simplest C-N bond carrier.
{"title":"Identification of solid N2O in interstellar ices using open JWST data","authors":"V. Karteyeva, R. Nakibov, I. Petrashkevich, M. Medvedev, A. Vasyunin","doi":"10.1051/0004-6361/202557939","DOIUrl":"https://doi.org/10.1051/0004-6361/202557939","url":null,"abstract":"<i>Context.<i/> Only six molecules containing an N-O bond are detected in the gaseous phase of the interstellar medium. One of them is nitrous oxide (N<sub>2<sub/>O), which was unsuccessfully searched for in solid form since the launch of the Infrared Space Observatory (ISO) mission. The observational capabilities of the <i>James Webb<i/> Space Telescope (JWST) present the possibility of identifying solid interstellar N<sub>2<sub/>O.<i>Aims.<i/> We aim to identify nitrous oxide in open JWST spectra of interstellar ices toward a sample of Class 0, 0/I, and flat protostars using the relevant laboratory mixtures of N<sub>2<sub/>O-bearing interstellar ice analogs.<i>Methods.<i/> A set of laboratory infrared transmission spectra was obtained for the following mixtures: N<sub>2<sub/>O:CO<sub>2<sub/> = 1:20, N<sub>2<sub/>O:CO = 1:20, N<sub>2<sub/>O:N<sub>2<sub/> = 1:20, N<sub>2<sub/>O:CO<sub>2<sub/>:CO = 1:15:5, and N<sub>2<sub/>O:CO<sub>2<sub/>:N<sub>2<sub/> = 1:15:13 at 10–23 K. A search for N<sub>2<sub/>O in JWST NIRSpec spectra toward 50 protostars was performed by fitting the 4.44–4.47 μm (2250–2235 cm<sup>−1<sup/>) NN-stretch absorption band with new laboratory mixtures of N<sub>2<sub/>O-bearing ices.<i>Results.<i/> We claim the first secure identification of N<sub>2<sub/>O in 16 protostars. The fitting results show that N<sub>2<sub/>O is formed predominantly within the apolar layer of the ice mantles, which are rich in CO, CO<sub>2<sub/>, and N<sub>2<sub/>. The abundance of solid N<sub>2<sub/>O is estimated at 0.2–2.1% relative to solid CO. We present the band strengths for N<sub>2<sub/>O in the mixtures corresponding to the apolar layer. We also report the identification of the C-N stretch band at 4.42 μm (2260 cm<sup>−1<sup/>), which we tentatively assign to HNCO, the simplest C-N bond carrier.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"295 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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