Pub Date : 2020-03-16DOI: 10.1051/0004-6361/201937222
M. Lafarga, I. Ribas, C. Lovis, M. Perger, M. Zechmeister, F. Bauer, M. Kürster, M. Cortés-Contreras, J. C. Morales, E. Herrero, A. Rosich, D. Baroch, A. Reiners, J. A. Caballero, A. Quirrenbach, P. Amado, J. M. Alacid, V. Béjar, S. Dreizler, A. Hatzes, T. Henning, S. Jeffers, A. Kaminski, D. Montes, S. Pedraz, C. Rodríguez-López, J. H. M. M. Schmitt
Context. For years, the standard procedure to measure radial velocities (RVs) of spectral observations consisted in cross-correlating the spectra with a binary mask, that is, a simple stellar template that contains information on the position and strength of stellar absorption lines. The cross-correlation function (CCF) profiles also provide several indicators of stellar activity. Aims. We present a methodology to first build weighted binary masks and, second, to compute the CCF of spectral observations with these masks from which we derive radial velocities and activity indicators. These methods are implemented in a python code that is publicly available. Methods. To build the masks, we selected a large number of sharp absorption lines based on the profile of the minima present in high signal-to-noise ratio (S/N) spectrum templates built from observations of reference stars. We computed the CCFs of observed spectra and derived RVs and the following three standard activity indicators: full-width-at-half-maximum as well as contrast and bisector inverse slope. Results. We applied our methodology to CARMENES high-resolution spectra and obtain RV and activity indicator time series of more than 300 M dwarf stars observed for the main CARMENES survey. Compared with the standard CARMENES template matching pipeline, in general we obtain more precise RVs in the cases where the template used in the standard pipeline did not have enough S/N. We also show the behaviour of the three activity indicators for the active star YZ CMi and estimate the absolute RV of the M dwarfs analysed using the CCF RVs.
背景多年来，测量光谱观测径向速度（RVs）的标准程序是将光谱与双掩模（即包含恒星吸收线位置和强度信息的简单恒星模板）进行交叉相关。交叉相关函数（CCF）剖面还提供了恒星活动的一些指标。我们提出了一种方法，首先建立加权二元掩模，其次计算使用这些掩模进行光谱观测的 CCF，并从中得出径向速度和活动指标。这些方法通过公开的 python 代码实现。为了建立掩模，我们根据参考恒星观测数据建立的高信噪比（S/N）光谱模板中存在的极小值轮廓，选择了大量尖锐的吸收线。我们计算了观测到的光谱的 CCFs 和得出的 RVs，以及以下三个标准活动指标：半最大全宽、对比度和平分线反斜率。我们将我们的方法应用于CARMENES高分辨率光谱，获得了CARMENES主巡天观测到的300多颗M矮星的RV和活动指标时间序列。与标准的CARMENES模板匹配管道相比，在标准管道使用的模板信噪比不足的情况下，我们通常能获得更精确的RV。我们还展示了活动恒星 YZ CMi 的三个活动指标的表现，并利用 CCF RVs 估算了所分析的 M 矮星的绝对 RV。
{"title":"The CARMENES search for exoplanets around M dwarfs","authors":"M. Lafarga, I. Ribas, C. Lovis, M. Perger, M. Zechmeister, F. Bauer, M. Kürster, M. Cortés-Contreras, J. C. Morales, E. Herrero, A. Rosich, D. Baroch, A. Reiners, J. A. Caballero, A. Quirrenbach, P. Amado, J. M. Alacid, V. Béjar, S. Dreizler, A. Hatzes, T. Henning, S. Jeffers, A. Kaminski, D. Montes, S. Pedraz, C. Rodríguez-López, J. H. M. M. Schmitt","doi":"10.1051/0004-6361/201937222","DOIUrl":"https://doi.org/10.1051/0004-6361/201937222","url":null,"abstract":"Context. For years, the standard procedure to measure radial velocities (RVs) of spectral observations consisted in cross-correlating the spectra with a binary mask, that is, a simple stellar template that contains information on the position and strength of stellar absorption lines. The cross-correlation function (CCF) profiles also provide several indicators of stellar activity.\u0000Aims. We present a methodology to first build weighted binary masks and, second, to compute the CCF of spectral observations with these masks from which we derive radial velocities and activity indicators. These methods are implemented in a python code that is publicly available.\u0000Methods. To build the masks, we selected a large number of sharp absorption lines based on the profile of the minima present in high signal-to-noise ratio (S/N) spectrum templates built from observations of reference stars. We computed the CCFs of observed spectra and derived RVs and the following three standard activity indicators: full-width-at-half-maximum as well as contrast and bisector inverse slope.\u0000Results. We applied our methodology to CARMENES high-resolution spectra and obtain RV and activity indicator time series of more than 300 M dwarf stars observed for the main CARMENES survey. Compared with the standard CARMENES template matching pipeline, in general we obtain more precise RVs in the cases where the template used in the standard pipeline did not have enough S/N. We also show the behaviour of the three activity indicators for the active star YZ CMi and estimate the absolute RV of the M dwarfs analysed using the CCF RVs.","PeriodicalId":48759,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2020-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141222538","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 : 2020-03-01DOI: 10.1051/0004-6361/202037867
G. Nowak, R. Luque, H. Parviainen, E. Pallé, K. Molaverdikhani, V. Béjar, J. Lillo-Box, C. Rodríguez-López, J. A. Caballero, M. Zechmeister, V. Passegger, C. Cifuentes, A. Schweitzer, N. Narita, B. Cale, N. Espinoza, F. Murgas, D. Hidalgo, M. R. Z. Osorio, F. Pozuelos, F. Aceituno, P. Amado, K. Barkaoui, D. Barrado, F. Bauer, Z. Benkhaldoun, D. Caldwell, N. C. Barris, P. Chaturvedi, Guo-qing Chen, K. Collins, K. Collins, M. Cortés-Contreras, I. Crossfield, J. D. Leon, E. D. Alonso, S. Dreizler, M. E. Mufti, E. Esparza-Borges, Z. Essack, A. Fukui, E. Gaidos, M. Gillon, E. Gonzales, P. Guerra, A. Hatzes, T. Henning, E. Herrero, K. Hesse, T. Hirano, S. Howell, S. Jeffers, E. Jehin, J. Jenkins, A. Kaminski, J. Kemmer, J. Kielkopf, D. Kossakowski, T. Kotani, M. Kürster, M. Lafarga, D. Latham, Nicholas Law, Jack J. Lissauer, N. Lodieu, A. Madrigal-Aguado, A. Mann, B. Massey, R. Matson, E. Matthews, P. Montañés-Rodríguez, D. Montes, J. C. Morales, M. Mori, E. Nagel, M. Oshagh, S. Pedraz, P. Plavchan, D. Pollacco
We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d⋆ ≈ 22 pc), bright (J ≈ 9 mag) M3.5 dwarf LTT 3780 (TOI–732). We confirm both planets and their association with LTT 3780 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high-resolution spectra confirm that LTT 3780 is a mid-M dwarf with an effective temperature of Teff = 3360 ± 51 K, a surface gravity of log g⋆ = 4.81 ± 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 ± 0.16 dex, with an inferred mass of M⋆ = 0.379 ± 0.016M⊙ and a radius of R⋆ = 0.382 ± 0.012R⊙. The ultra-short-period planet LTT 3780 b (Pb = 0.77 d) with a radius of 1.35−0.06+0.06 R⊕, a mass of 2.34−0.23+0.24 M⊕, and a bulk density of 5.24−0.81+0.94 g cm−3 joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LTT 3780 c, with an orbital period of 12.25 d, radius of 2.42−0.10+0.10 R⊕, mass of 6.29−0.61+0.63 M⊕, and mean density of 2.45−0.37+0.44 g cm−3 belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is anexcellent target for testing planetary formation, evolution, and atmospheric models. In particular, LTT 3780 c is an ideal object for atmospheric studies with the James Webb Space Telescope (JWST).
{"title":"The CARMENES search for exoplanets around M dwarfs","authors":"G. Nowak, R. Luque, H. Parviainen, E. Pallé, K. Molaverdikhani, V. Béjar, J. Lillo-Box, C. Rodríguez-López, J. A. Caballero, M. Zechmeister, V. Passegger, C. Cifuentes, A. Schweitzer, N. Narita, B. Cale, N. Espinoza, F. Murgas, D. Hidalgo, M. R. Z. Osorio, F. Pozuelos, F. Aceituno, P. Amado, K. Barkaoui, D. Barrado, F. Bauer, Z. Benkhaldoun, D. Caldwell, N. C. Barris, P. Chaturvedi, Guo-qing Chen, K. Collins, K. Collins, M. Cortés-Contreras, I. Crossfield, J. D. Leon, E. D. Alonso, S. Dreizler, M. E. Mufti, E. Esparza-Borges, Z. Essack, A. Fukui, E. Gaidos, M. Gillon, E. Gonzales, P. Guerra, A. Hatzes, T. Henning, E. Herrero, K. Hesse, T. Hirano, S. Howell, S. Jeffers, E. Jehin, J. Jenkins, A. Kaminski, J. Kemmer, J. Kielkopf, D. Kossakowski, T. Kotani, M. Kürster, M. Lafarga, D. Latham, Nicholas Law, Jack J. Lissauer, N. Lodieu, A. Madrigal-Aguado, A. Mann, B. Massey, R. Matson, E. Matthews, P. Montañés-Rodríguez, D. Montes, J. C. Morales, M. Mori, E. Nagel, M. Oshagh, S. Pedraz, P. Plavchan, D. Pollacco","doi":"10.1051/0004-6361/202037867","DOIUrl":"https://doi.org/10.1051/0004-6361/202037867","url":null,"abstract":"We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d⋆ ≈ 22 pc), bright (J ≈ 9 mag) M3.5 dwarf LTT 3780 (TOI–732). We confirm both planets and their association with LTT 3780 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high-resolution spectra confirm that LTT 3780 is a mid-M dwarf with an effective temperature of Teff = 3360 ± 51 K, a surface gravity of log g⋆ = 4.81 ± 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 ± 0.16 dex, with an inferred mass of M⋆ = 0.379 ± 0.016M⊙ and a radius of R⋆ = 0.382 ± 0.012R⊙. The ultra-short-period planet LTT 3780 b (Pb = 0.77 d) with a radius of 1.35−0.06+0.06 R⊕, a mass of 2.34−0.23+0.24 M⊕, and a bulk density of 5.24−0.81+0.94 g cm−3 joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LTT 3780 c, with an orbital period of 12.25 d, radius of 2.42−0.10+0.10 R⊕, mass of 6.29−0.61+0.63 M⊕, and mean density of 2.45−0.37+0.44 g cm−3 belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is anexcellent target for testing planetary formation, evolution, and atmospheric models. In particular, LTT 3780 c is an ideal object for atmospheric studies with the James Webb Space Telescope (JWST).","PeriodicalId":48759,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141226397","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 : 2020-03-01DOI: 10.1051/0004-6361/201937050
E. González-Álvarez, M. R. Z. Osorio, J. A. Caballero, J. Sanz-Forcada, V. Béjar, L. González-Cuesta, S. Dreizler, F. Bauer, E. Rodríguez, L. Tal-Or, M. Zechmeister, D. Montes, M. J. López-González, I. Ribas, A. Reiners, A. Quirrenbach, P. Amado, G. Anglada-Escudé, M. Azzaro, M. Cortés-Contreras, A. Hatzes, T. Henning, S. Jeffers, A. Kaminski, M. Kürster, M. Lafarga, J. C. Morales, E. Pallé, M. Perger, J. H. M. M. Schmitt
Aims. We report on radial velocity time series for two M0.0 V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence of small planets in tight orbits using the spectroscopic radial velocity technique. Methods. We obtained 159 and 70 radial velocity measurements of GJ 338 B and A, respectively, with the CARMENES visible channel between 2016 January and 2018 October. We also compiled additional relative radial velocity measurements from the literature and a collection of astrometric data that cover 200 a of observations to solve for the binary orbit. Results. We found dynamical masses of 0.64 ± 0.07 M⊙ for GJ 338 B and 0.69 ± 0.07 M⊙ for GJ 338 A. The CARMENES radial velocity periodograms show significant peaks at 16.61 ± 0.04 d (GJ 338 B) and 16.3−1.3+3.5 d (GJ 338 A), which have counterparts at the same frequencies in CARMENES activity indicators and photometric light curves. We attribute these to stellar rotation. GJ 338 B shows two additional, significant signals at 8.27 ± 0.01 and 24.45 ± 0.02 d, with no obvious counterparts in the stellar activity indices. The former is likely the first harmonic of the star’s rotation, while we ascribe the latter to the existence of a super-Earth planet with a minimum mass of 10.27−1.38+1.47 M⊕ orbiting GJ 338 B. We have not detected signals of likely planetary origin around GJ 338 A. Conclusions. GJ 338 Bb lies inside the inner boundary of the habitable zone around its parent star. It is one of the least massive planets ever found around any member of stellar binaries. The masses, spectral types, brightnesses, and even the rotational periods are very similar for both stars, which are likely coeval and formed from the same molecular cloud, yet they differ in the architecture of their planetary systems.
{"title":"The CARMENES search for exoplanets around M dwarfs","authors":"E. González-Álvarez, M. R. Z. Osorio, J. A. Caballero, J. Sanz-Forcada, V. Béjar, L. González-Cuesta, S. Dreizler, F. Bauer, E. Rodríguez, L. Tal-Or, M. Zechmeister, D. Montes, M. J. López-González, I. Ribas, A. Reiners, A. Quirrenbach, P. Amado, G. Anglada-Escudé, M. Azzaro, M. Cortés-Contreras, A. Hatzes, T. Henning, S. Jeffers, A. Kaminski, M. Kürster, M. Lafarga, J. C. Morales, E. Pallé, M. Perger, J. H. M. M. Schmitt","doi":"10.1051/0004-6361/201937050","DOIUrl":"https://doi.org/10.1051/0004-6361/201937050","url":null,"abstract":"Aims. We report on radial velocity time series for two M0.0 V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence of small planets in tight orbits using the spectroscopic radial velocity technique.\u0000Methods. We obtained 159 and 70 radial velocity measurements of GJ 338 B and A, respectively, with the CARMENES visible channel between 2016 January and 2018 October. We also compiled additional relative radial velocity measurements from the literature and a collection of astrometric data that cover 200 a of observations to solve for the binary orbit.\u0000Results. We found dynamical masses of 0.64 ± 0.07 M⊙ for GJ 338 B and 0.69 ± 0.07 M⊙ for GJ 338 A. The CARMENES radial velocity periodograms show significant peaks at 16.61 ± 0.04 d (GJ 338 B) and 16.3−1.3+3.5 d (GJ 338 A), which have counterparts at the same frequencies in CARMENES activity indicators and photometric light curves. We attribute these to stellar rotation. GJ 338 B shows two additional, significant signals at 8.27 ± 0.01 and 24.45 ± 0.02 d, with no obvious counterparts in the stellar activity indices. The former is likely the first harmonic of the star’s rotation, while we ascribe the latter to the existence of a super-Earth planet with a minimum mass of 10.27−1.38+1.47 M⊕ orbiting GJ 338 B. We have not detected signals of likely planetary origin around GJ 338 A.\u0000Conclusions. GJ 338 Bb lies inside the inner boundary of the habitable zone around its parent star. It is one of the least massive planets ever found around any member of stellar binaries. The masses, spectral types, brightnesses, and even the rotational periods are very similar for both stars, which are likely coeval and formed from the same molecular cloud, yet they differ in the architecture of their planetary systems.","PeriodicalId":48759,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141225608","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 : 2020-03-01DOI: 10.1051/0004-6361/201629932e
R. Klement, A. Carciofi, T. Rivinius, L. D. Matthews, R. G. Vieira, R. Ignace, J. E. Bjorkman, B. Mota, D. Faes, A. Bratcher, M. Curé, S. Štefl
1 European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001 Santiago, Chile e-mail: robertklement@gmail.com 2 Astronomical Institute of Charles University, Charles University, V Holešovičkách 2, 180 00 Prague 8, Troja, Czech Republic 3 Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, 05508-090 São Paulo, SP, Brazil 4 MIT Haystack Observatory, off Route 40, Westford, MA 01886, USA 5 Department of Physics & Astronomy, East Tennessee State University, Box 70652, Johnson City, TN 37614, USA 6 Ritter Observatory, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA 7 Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Casilla 5030 Valparaíso, Chile
1 European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001 Santiago, Chile e-mail：robertklement@gmail.com 2 Astronomical Institute of Charles University, Charles University, V Holešovičkách 2, 180 00 Prague 8, Troja, Czech Republic 3 Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, 05508-090 São Paulo, SP, Brazil 4 MIT Haystack Observatory, off Route 40、Westford, MA 01886, USA 5 Department of Physics & Astronomy, East Tennessee State University, Box 70652, Johnson City, TN 37614, USA 6 Ritter Observatory, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA 7 Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Casilla 5030 Valparaíso, Chile
{"title":"Revealing the structure of the outer disks of Be stars (Corrigendum)","authors":"R. Klement, A. Carciofi, T. Rivinius, L. D. Matthews, R. G. Vieira, R. Ignace, J. E. Bjorkman, B. Mota, D. Faes, A. Bratcher, M. Curé, S. Štefl","doi":"10.1051/0004-6361/201629932e","DOIUrl":"https://doi.org/10.1051/0004-6361/201629932e","url":null,"abstract":"1 European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001 Santiago, Chile e-mail: robertklement@gmail.com 2 Astronomical Institute of Charles University, Charles University, V Holešovičkách 2, 180 00 Prague 8, Troja, Czech Republic 3 Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, 05508-090 São Paulo, SP, Brazil 4 MIT Haystack Observatory, off Route 40, Westford, MA 01886, USA 5 Department of Physics & Astronomy, East Tennessee State University, Box 70652, Johnson City, TN 37614, USA 6 Ritter Observatory, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA 7 Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Casilla 5030 Valparaíso, Chile","PeriodicalId":48759,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141225658","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 : 2020-03-01DOI: 10.1051/0004-6361/201732393
P. Bordé, R. F. Díaz, O. Creevey, C. Damiani, H. Deeg, P. Klagyivik, G. Wuchterl, D. Gandolfi, M. Fridlund, F. Bouchy, S. Aigrain, R. Alonso, J. Almenara, A. Baglin, S. Barros, A. Bonomo, J. Cabrera, S. Csizmadia, M. Deleuil, A. Erikson, S. Ferraz-Mello, E. Guenther, T. Guillot, S. Grziwa, A. Hatzes, G. Hébrard, T. Mazeh, M. Ollivier, H. Parviainen, M. Pätzold, H. Rauer, D. Rouan, A. Santerne, J. Schneider
Aims. We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope. Methods. We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To derive the absolute masses and radii of the planets, we modeled the stars from available magnitudes and spectra. Results. We find that CoRoT-30 b is a warm Jupiter on a close-to-circular 9.06-day orbit around a G3V star with a semi-major axis of about 0.08 AU. It has a radius of 1.01 ± 0.08 RJ, a mass of 2.90 ± 0.22 MJ, and therefore a mean density of 3.45 ± 0.65 g cm−3. The hot Jupiter CoRoT-31 b is on a close-to-circular 4.63-day orbit around a G2 IV star with a semi-major axis of about 0.05 AU. It has a radius of 1.46 ± 0.30 RJ, a mass of 0.84 ± 0.34 MJ, and therefore a mean density of 0.33 ± 0.18 g cm−3. Conclusions. Neither system seems to support the claim that stars hosting planets are more depleted in lithium. The radii of both planets are close to that of Jupiter, but they differ in mass; CoRoT-30 b is ten times denser than CoRoT-31 b. The core of CoRoT-30 b would weigh between 15 and 75 Earth masses, whereas relatively weak constraints favor no core for CoRoT-31 b. In terms of evolution, the characteristics of CoRoT-31 b appear to be compatible with the high-eccentricity migration scenario, which is not the case for CoRoT-30 b. The angular momentum of CoRoT-31 b is currently too low for the planet to evolve toward synchronization of its orbital revolution with stellar rotation, and the planet will slowly spiral-in while its host star becomes a red giant. CoRoT-30 b is not synchronized either: it looses angular momentum owing to stellar winds and is expected reach steady state in about 2 Gyr. CoRoT-30 and 31, as a pair, are a truly remarkable example of diversity in systems with hot Jupiters.
目的。我们报告了利用 CoRoT 太空望远镜发现的两颗新的凌日巨型系外行星 CoRoT-30 b 和 CoRoT-31 b，以及它们的轨道和物理特征。我们分析了两组互补数据：CoRoT测量的测光凌日光变曲线和HARPS光谱仪测量的径向速度曲线。为了得出行星的绝对质量和半径，我们根据现有的星等和光谱对恒星进行了建模。我们发现，CoRoT-30 b 是一颗暖木星，围绕一颗半长轴约为 0.08 AU 的 G3V 恒星运行，轨道接近圆形，长 9.06 天。它的半径为 1.01 ± 0.08 RJ，质量为 2.90 ± 0.22 MJ，因此平均密度为 3.45 ± 0.65 g cm-3。热木星 CoRoT-31 b 围绕一颗半长轴约为 0.05 AU 的 G2 IV 恒星运行在一个近似圆形的 4.63 天轨道上。它的半径为 1.46 ± 0.30 RJ，质量为 0.84 ± 0.34 MJ，因此平均密度为 0.33 ± 0.18 g cm-3。这两个系统似乎都不支持寄宿行星的恒星锂消耗更多的说法。两颗行星的半径都接近木星，但它们的质量不同；CoRoT-30 b 的密度是 CoRoT-31 b 的十倍。CoRoT-30 b 的内核重量在 15 到 75 个地球质量之间，而相对较弱的约束条件表明 CoRoT-31 b 没有内核。CoRoT-31 b目前的角动量太小，行星无法朝着轨道旋转与恒星自转同步的方向演化，在其宿主恒星变为红巨星的同时，行星将缓慢旋入。CoRoT-30 b也不是同步的：由于恒星风的作用，它失去了角动量，预计将在大约2 Gyr后达到稳定状态。CoRoT-30和31作为一对，是热木星系统多样性的一个真正显著的例子。
{"title":"Transiting exoplanets from the CoRoT space mission","authors":"P. Bordé, R. F. Díaz, O. Creevey, C. Damiani, H. Deeg, P. Klagyivik, G. Wuchterl, D. Gandolfi, M. Fridlund, F. Bouchy, S. Aigrain, R. Alonso, J. Almenara, A. Baglin, S. Barros, A. Bonomo, J. Cabrera, S. Csizmadia, M. Deleuil, A. Erikson, S. Ferraz-Mello, E. Guenther, T. Guillot, S. Grziwa, A. Hatzes, G. Hébrard, T. Mazeh, M. Ollivier, H. Parviainen, M. Pätzold, H. Rauer, D. Rouan, A. Santerne, J. Schneider","doi":"10.1051/0004-6361/201732393","DOIUrl":"https://doi.org/10.1051/0004-6361/201732393","url":null,"abstract":"Aims. We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope.\u0000Methods. We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To derive the absolute masses and radii of the planets, we modeled the stars from available magnitudes and spectra.\u0000Results. We find that CoRoT-30 b is a warm Jupiter on a close-to-circular 9.06-day orbit around a G3V star with a semi-major axis of about 0.08 AU. It has a radius of 1.01 ± 0.08 RJ, a mass of 2.90 ± 0.22 MJ, and therefore a mean density of 3.45 ± 0.65 g cm−3. The hot Jupiter CoRoT-31 b is on a close-to-circular 4.63-day orbit around a G2 IV star with a semi-major axis of about 0.05 AU. It has a radius of 1.46 ± 0.30 RJ, a mass of 0.84 ± 0.34 MJ, and therefore a mean density of 0.33 ± 0.18 g cm−3.\u0000Conclusions. Neither system seems to support the claim that stars hosting planets are more depleted in lithium. The radii of both planets are close to that of Jupiter, but they differ in mass; CoRoT-30 b is ten times denser than CoRoT-31 b. The core of CoRoT-30 b would weigh between 15 and 75 Earth masses, whereas relatively weak constraints favor no core for CoRoT-31 b. In terms of evolution, the characteristics of CoRoT-31 b appear to be compatible with the high-eccentricity migration scenario, which is not the case for CoRoT-30 b. The angular momentum of CoRoT-31 b is currently too low for the planet to evolve toward synchronization of its orbital revolution with stellar rotation, and the planet will slowly spiral-in while its host star becomes a red giant. CoRoT-30 b is not synchronized either: it looses angular momentum owing to stellar winds and is expected reach steady state in about 2 Gyr. CoRoT-30 and 31, as a pair, are a truly remarkable example of diversity in systems with hot Jupiters.","PeriodicalId":48759,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141226296","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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