Astronomy & Astrophysics最新文献

{"title":"A quasar-galaxy merger at z~6.2: Rapid host growth via the accretion of two massive satellite galaxies","authors":"R. Decarli, F. Loiacono, Emanuele Paolo Farina, M. Dotti, Alessandro Lupi, A. Romain Meyer, M. Mignoli, A. Pensabene, A. Michael Strauss, B. Venemans, Jinyi Yang, Fabian Walter, Julien Wolf","doi":"10.1051/0004-6361/202449239","DOIUrl":"https://doi.org/10.1051/0004-6361/202449239","url":null,"abstract":"We present JWST/NIRSpec integral field spectroscopy in the rest-frame optical bands of the system PJ308--21, a quasar at $z=6.2342$ caught as its host galaxy interacts with companion galaxies. We detect the spatially extended emission of several emission lines ( and ), which we used to study the properties of the ionized phase of the interstellar medium: the source and hardness of the photoionizing radiation field, metallicity, dust reddening, electron density and temperature, and star formation. We also marginally detected continuum starlight emission associated with the companion sources. We find that at least two independent satellite galaxies are part of the system. While the quasar host appears highly enriched and obscured, with photoionization conditions typical of an Active Galactic Nucleus, the western companion shows minimal dust extinction, low metallicity ($Z and star formation driven photoionization. The eastern companion shows higher extinction and metallicity ($Z compared to the western companion, and it is at least partially photoionized by the nearby quasar. We do not find any indication of AGN in the companion sources. Our study shows that while the quasar host galaxy is already very massive dyn it is still rapidly building up by accreting two relatively massive star companion sources. This dataset showcases the power of JWST in exposing the buildup of massive galaxies in the first gigayear of the Universe.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"26 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141684524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of the interstellar cyanoacetylene radical cation HC_3N+","authors":"C. Cabezas, M. Ag'undez, Y. Endo, B. Tercero, N. Marcelino, P. D. Vicente, J. Cernicharo","doi":"10.1051/0004-6361/202451081","DOIUrl":"https://doi.org/10.1051/0004-6361/202451081","url":null,"abstract":"We report the first identification in space of HC$_3$N$^+$, the simplest member of the family\u0000of cyanopolyyne cations. Three rotational transitions with half-integer quantum numbers from $J$=7/2 to\u000011/2 have been observed with the Yebes 40m radio telescope and assigned to HC$_3$N$^+$, which has an inverted\u0000$^2 ground electronic state. The three rotational transitions exhibit several hyperfine components due to the magnetic and nuclear quadrupole coupling effects of the H and N nuclei. We confidently assign the characteristic rotational spectrum pattern to HC$_3$N$^+$ based on the good agreement between the astronomical and theoretical spectroscopic parameters. We derived a column density of (6.0pm 0.6)times 1010 $ and a rotational temperature of 4.5pm 1,K. The abundance ratio between HC$_3$N and HC$_3$N$^+$ is 3200pm 320. As found for the larger members of the family of cyanopolyyne cations (HC$_5$N$^+$ and HC$_7$N$^+$), HC$_3$N$^+$ is mainly formed through the reactions of H$_2$ and the cation C$_3$N$^+$ and by the reactions of H$^+$ with HC$_3$N. In the same manner than other cyanopolyyne cations, HC$_3$N$^+$ is mostly destroyed through a reaction with H$_2$ and a dissociative recombination with electrons.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"68 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141688289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multipoint study of the rapid filament evolution during a confined C2 flare on 28 March 2022, leading to eruption","authors":"S. Purkhart, A. Veronig, B. Kliem, R. Jarolim, K. Dissauer, E. Dickson, T. Podladchikova, S. Krucker","doi":"10.1051/0004-6361/202450092","DOIUrl":"https://doi.org/10.1051/0004-6361/202450092","url":null,"abstract":"This study focuses on the rapid evolution of the solar filament in active region 12975 during a confined C2 flare on 28 March 2022, which finally led to an eruptive M4 flare 1.5 h later. The event is characterized by the apparent breakup of the filament, the disappearance of its southern half, and the flow of the remaining filament plasma into a new, longer channel with a topology very similar to an extreme ultraviolet (EUV) hot channel observed during the flare. In addition, we outline the emergence of the original filament from a sheared arcade and discuss possible drivers for its rise and eruption. We took advantage of Solar Orbiter's favorable position, 0.33 AU from the Sun, and $83. 5^ west of the Sun-Earth line, to perform a multi-point study using the Spectrometer Telescope for Imaging X-rays (STIX) and the Extreme Ultraviolet Imager (EUI) in combination with the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) and Halpha images from the Earth-based Kanzelhöhe Observatory for Solar and Environmental Research (KSO) and the Global Oscillation Network Group (GONG). While STIX and EUI observed the flare and the filament's rise from close up and at the limb, AIA and HMI observations provided highly complementary on-disk observations from which we derived differential emission measure (DEM) maps and nonlinear force-free (NLFF) magnetic field extrapolations. According to our pre-flare NLFF extrapolation, field lines corresponding to both filament channels existed in close proximity before the flare. We propose a loop-loop reconnection scenario based on field structures associated with the AIA 1600 Å flare ribbons and kernels. It involves field lines surrounding and passing beneath the shorter filament channel, and field lines closely following the southern part of the longer channel. Reconnection occurs in an essentially vertical current sheet at a polarity inversion line (PIL) below the breakup region, which enables the formation of the flare loop arcade and EUV hot channel. This scenario is supported by concentrated currents and free magnetic energy built up by antiparallel flows along the PIL before the flare, and by non-thermal X-ray emission observed from the reconnection region. The reconnection probably propagated to involve the original filament itself, leading to its breakup and new geometry. This reconnection geometry also provides a general mechanism for the formation of the long filament channel and realizes the concept of tether cutting. It was probably active throughout the filament's continuous rise phase, which lasted from at least 30 min before the C2 flare until the filament eruption. The C2 flare represents a period of fast reconnection during this otherwise more steady period, during which most of the original filament was reconnected and joined the longer channel. These results demonstrate how rapid changes in solar filament topology can be driven b","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"14 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141684807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MICONIC: JWST/MIRI MRS observations of the nuclear\u0000 and circumnuclear regions of Mrk 231","authors":"A. Alonso-Herrero, L. H. Muñoz, Á. Labiano, P. Guillard, V. Buiten, D. Dicken, P. V. D. Werf, J. 'Alvarez-M'arquez, T. Boker, L. Colina, A. Eckart, M. Garc'ia-Mar'in, O. C. Jones, L. Pantoni, P. G. P'erez-Gonz'alez, D. Rouan, M. Ward, M. Baes, G. Ostlin, P. Royer, G. Wright, M. Gudel, T. Henning, P. Lagage, E. V. Dishoeck","doi":"10.1051/0004-6361/202450071","DOIUrl":"https://doi.org/10.1051/0004-6361/202450071","url":null,"abstract":"We present JWST/MIRI MRS spatially resolved $ observations of the central $ 4-8,$kpc of the ultraluminous infrared galaxy and broad absorption line quasar Mrk 231. These are part of the Mid-Infrared Characterization of Nearby Iconic galaxy Centers (MICONIC) program of the MIRI European Consortium guaranteed time observations. No high excitation lines (i.e. v at $5.61 or v at\u0000 $14.32 typically associated with the presence of an active galactic nucleus (AGN) are detected in the nuclear region of Mrk 231. This is likely due to the intrinsically X-ray weak nature of its quasar. Some intermediate ionization potential lines, for instance iii at $8.99 and iv at \u0000 $10.51 are not detected either, even though they are clearly observed in a star-forming region $ 920,$pc south-east of the AGN. Thus, the strong nuclear mid-infrared (mid-IR) continuum is also in part hampering the detection of faint lines in the nuclear region. The nuclear iii ii line \u0000 ratio is consistent with values observed in star-forming galaxies. Moreover, we\u0000 resolve for the first time the nuclear starburst in the mid-IR \u0000 low-excitation line\u0000 emission (size of $ 400,$pc, FWHM). Several pieces of evidence also indicate that it is partly obscured even at these wavelengths. At the AGN position, the ionized and warm molecular gas emission lines have modest widths km,s $). There are, however,\u0000 weak blueshifted wings reaching velocities $v_ km,s $ in ii . The nuclear\u0000 starburst is at the center of a large ($ 8,$kpc), massive rotating disk with widely-spread, low velocity outflows. Given the high star formation rate of Mrk 231, we speculate that part of the nuclear outflows and the large-scale non-circular motions observed in the mid-IR are driven by its powerful nuclear starburst.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141685895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the imprint of active galactic nucleus feedback in Seyfert galaxies. Nuclear-scale molecular gas deficits","authors":"S. Garcia-Burillo, E. Hicks, A. Alonso-Herrero, M. Pereira-Santaella, A. Usero, M. Querejeta, O. González-Martín, D. Delaney, C. Ramos Almeida, F. Combes, D. Angles-Alcazar, A. Audibert, E. Bellocchi, R. Davies, T. A. Davis, J. Elford, I. Garcia-Bernete, S. Honig, Á. Labiano, M. Leist, N. Levenson, E. Lopez-Rodriguez, J. Mercedes-Feliz, C. Packham, C. Ricci, D. Rosario, T. Shimizu, M. Stalevski, L. Zhang","doi":"10.1051/0004-6361/202450268","DOIUrl":"https://doi.org/10.1051/0004-6361/202450268","url":null,"abstract":"We study the distribution\u0000of cold molecular gas in the circumunuclear disks (CND; $r pc) of a sample of 64 nearby L $=7-45 Mpc) disk galaxies ---including 45 active galactic nuclei (AGN) and 19 nonAGN--- for which high-spatial-resolution (median value $ pc) multiline CO interferometer observations have been obtained at millimeter wavelengths with the Atacama Large Millimeter Array (ALMA) and/or Plateau de Bure Interferometer (PdBI). We decipher whether or not the concentration and normalized radial distribution of cold molecular gas change as a function of X-ray luminosity in the 2--10 keV range X $) in order to analyze\u0000the imprint left by AGN feedback. We also look for similar trends in the concentration and normalized radial distribution of the hot molecular gas and in the hot-to-cold-molecular gas mass ratio in a subset of 35 galaxies using near-infrared (NIR) integral field spectroscopy data obtained for the H$_2$ 1-0 S(1) line. We find a significant turnover in the distribution of the cold molecular gas concentration as a function of X-ray luminosity with a breakpoint that divides the sample into two branches: (1) the `AGN build-up branch'' ($L_ X pm0.3 $erg s$^ $) and (2) the ``AGN feedback branch'' ($L_ X pm0.3 $erg s$^ $) . Lower-luminosity AGN and nonAGN of the AGN build-up branch show high cold molecular gas concentrations and centrally peaked radial profiles on nuclear ($r pc) scales. Higher-luminosity AGN of the AGN feedback branch show a sharp decrease in the concentration of molecular gas and flat or inverted radial profiles. The cold molecular gas concentration index ($CCI$) --- defined as the ratio of surface densities at $r pc ($ gas $) and $r pc $( gas $), namely $CCI gas gas $)--- spans a 0.63 dex range, equivalent to a factor simeq 4-5, between the galaxies lying at the high end of the AGN build-up branch and the galaxies showing the most extreme nuclear-scale molecular gas deficits in the AGN feedback branch. The concentration and radial distributions of the hot molecular gas in our sample follow qualitatively similar but less extreme trends as a function of X-ray luminosity. As a result, we find higher values of hot-to-cold molecular gas mass ratios on nuclear scales in the highest luminosity AGN sources of the AGN feedback branch. These observations confirm ---with a three times larger sample--- previous evidence found in the context of the Galaxy Activity Torus and Outflow Survey (GATOS) that the imprint of AGN feedback on the CND-scale distribution of molecular gas is more extreme in higher luminosity Seyfert galaxies of the local Universe.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"311 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141686802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nova contributions to the chemical evolution of the Milky Way","authors":"A. Kemp, Amanda I Karakas, Andrew R. Casey, Benoit Cote, R. Izzard, Z. Osborn","doi":"10.1051/0004-6361/202450800","DOIUrl":"https://doi.org/10.1051/0004-6361/202450800","url":null,"abstract":"The explosive burning that drives nova eruptions results in unique nucleosynthesis that heavily over-produces certain isotopes relative to the solar abundance. However, novae are often ignored when considering the chemical evolution of our Galaxy due to their low ejecta masses. Galactic chemical evolution studies including novae are rare and have previously relied upon simplified treatments for the behaviour of nova populations. In this work, we use previously computed synthetic nova populations and the galactic chemical evolution code OMEGA+ to assess the impact that novae have on the evolution of stable elemental and isotopic abundances. We combine populations of novae computed using the binary population synthesis code with the galactic chemical evolution code OMEGA+ and detailed, white dwarf mass-dependent nova yields to model the nucleosynthetic contributions of novae to the evolution of the Milky Way. We consider three different nova yield profiles, each corresponding to a different set of nova yield calculations. We examine which nova sites contribute most to which isotopes. Despite novae from low-mass white dwarfs (WDs) dominating nova ejecta contributions, we find that novae occurring on massive WDs are still able to contribute significantly to many isotopes, particularly those with high mass numbers. We find that novae can produce up to 35 of the Galactic C and N mass by the time the model Galaxy reaches Fe/H = 0, and earlier in the evolution of the Galaxy (between Fe/H = -2 and -1) novae may have been the dominant source of N. Predictions for C/Fe N/Fe C/ C, and N/ N abundances ratios vary by up to 0.2 dex at Fe/H = 0 and by up to 0.7 dex in N/Fe and N/ N between Fe/H = -2 and -1 (corresponding approximately to Galactic ages of 170 Myr and 1 Gyr in our model). The Galactic evolution of other stable isotopes (excluding Li) is not noticeably affected by including novae. For most isotopes, agreement is generally good between the three different yield profiles we consider. Isotopes where agreement is relatively poor include: He (especially at high Li O F, and the >1.3 M regime of Si S S Cl, and Ar.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"2 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141686442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiwavelength study of on-disk coronal-hole jets with IRIS and SDO observations","authors":"Koletti Myrto, Gontikakis Costis, Patsourakos Spiros, Tsinganos Kanaris","doi":"10.1051/0004-6361/202348446","DOIUrl":"https://doi.org/10.1051/0004-6361/202348446","url":null,"abstract":"Solar jets are an important field of study, as they may contribute to the mass and energy transfer from the lower to the upper atmosphere. We use the Interface Region\u0000Imaging Spectrograph (IRIS) and Solar Dynamic Observatory (SDO) observations to study two small-scale jets (jet 1 and jet 2) originating in the same on-disk coronal hole observed in October 2013. We combine dopplergrams, intensity maps, and line width maps derived from IRIS Si IV 1393.755Å spectra along with images from the Atmospheric Imaging Assembly (AIA) on SDO\u0000to describe the dynamics of the jets. Images from AIA, with the use of the emission measure loci technique and rectangular differential emission measure (DEM) distributions, provide estimations\u0000of the plasma temperatures. We used the O IV spectral lines from IRIS to derive electron densities. For jet 1, the SDO images show a small mini-filament 2 minutes before the jet eruption, while jet 2 originates at a pre-existing coronal bright point. The analysis of asymmetric spectral profiles of the Si IV and 1402.770 lines reveals the existence of two spectral components with inversely dependant 1393.755 ratios at both regions. One of the components can be related to the background plasma emission originating outside the jet, while the secondary component represents higher-energy plasma flows associated with the jets. Both jets exhibit high densities of the order of 1011 $ at their\u0000base and 1010 cm$^ $ at the spire, respectively, as well as similar average nonthermal velocities of sim 50-60 km/s. However, the two jets show\u0000differences in their length, duration, and plane-of-sky velocity. Finally, the DEM analysis reveals that both jets exhibit multithermal distributions. This work presents a comprehensive description of the thermal parameters and the dynamic evolution of two jets.\u0000The locations of the asymmetric profiles possibly indicate the areas of energy release triggering the jets.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"6 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141686092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Projection factor and radii of Type II Cepheids. BL Her stars","authors":"P. Wielgórski, G. Pietrzyński, W. Gieren, B. Zgirski, M. Górski, J. Storm, N. Nardetto, P. Kervella, G. Bras, G. Hajdu, V. Hocdé, B. Pilecki, W. Narloch, P. Karczmarek, W. Pych, R. Chini, K. Hodapp","doi":"10.1051/0004-6361/202450182","DOIUrl":"https://doi.org/10.1051/0004-6361/202450182","url":null,"abstract":"Type II Cepheids are old pulsating stars that can be used to trace the distribution of an old stellar population and to measure distances to globular clusters and galaxies within several megaparsecs, and by extension, they can improve our understanding of the cosmic distance scale. One method that can be used to measure the distances of Type II Cepheids relies on period-luminosity relations, which are quite widely explored in the literature. The semi-geometrical Baade-Wesselink technique is another method that allows distances of radially pulsating stars, such as Type II Cepheids, to be measured if the so-called projection factor is known. However, the literature concerning this parameter for Type II Cepheids is limited to just a few pioneering works. In determining projection factors for eight nearby short-period Type II Cepheids, also known as BL Her type stars, we aim to calibrate the Baade-Wesselink method for measuring distances for this class of stars. Using the surface brightness-colour relation version of the Baade-Wesselink technique, we determined the projection factors and radii of eight nearby BL Her type stars. We adopted accurate distances of target stars from $Gaia$ Data Release 3. Time series photometry in the $V$ and $K_ S $ bands have been collected with two telescopes located at the $Rolf$ $Chini$ Cerro Murphy Observatory (former Cerro Armazones Observatory), while spectroscopic data have been obtained within dedicated programmes with instruments hosted by the European Southern Observatory. The measured projection factors for the stars with good quality data are in the range between 1.21 and 1.36. The typical uncertainty of projection factors is 0.1. The mean value is 1.330pm 0.058, which gives the uncertainty of sim 4. The main sources of uncertainty on the $p$-factors are statistical errors of the Baade-Wesselink fit (related to the dispersion and coverage of light and radial velocity curves) and parallax. In the case of radii, the biggest contribution to the error budget comes from the $K_ S $ band photometry's systematic uncertainty and parallax. The determined radii allowed us to construct the period-radius relation for BL Her stars. Our period-radius relation is in good agreement with the previous empirical calibration, while two theoretical calibrations found in the literature agree with our relation within 2sigma . We also confirm that BL Her and RR Lyr stars obey an apparent common period-radius relation.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"352 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141686503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterising planetary systems with SPIRou: Temperate sub-Neptune exoplanet orbiting the nearby fully convective star GJ 1289 and a candidate around GJ 3378","authors":"C. Moutou, M. Ould-Elhkim, J. Donati, P. Charpentier, C. Cadieux, X. Delfosse, E. Artigau, L. Arnold, C. Baruteau, A. Carmona, N. Cook, P. Cortes Zuleta, R. Doyon, G. Hébrard, the SLS consortium","doi":"10.1051/0004-6361/202450466","DOIUrl":"https://doi.org/10.1051/0004-6361/202450466","url":null,"abstract":"We report the discovery of two new exoplanet systems around fully convective stars, found from the radial-velocity (RV) variations of their host stars measured with the nIR spectropolarimeter CFHT/SPIRou over multiple years. GJ 3378 b is a planet with minimum mass of $5.26^ on an eccentric 24.73-day orbit around an M4V star of 0.26 GJ 1289 b has a minimum mass of $6.27 in a 111.74-day orbit, on a circular orbit around an M4.5V star of mass 0.21 Both stars are in the solar neighbourhood, at 7.73 and 8.86 pc, respectively. The low-amplitude RV signals are detected after line-by-line post-processing treatment. These potential sub-Neptune class planets around cool stars may have temperate atmospheres and be interesting nearby systems for further studies. We also recovered the large-scale magnetic field of both stars, found to be mostly axisymmetric and dipolar, with polar strengths of 20-30 G and 200-240 G for GJ 3378 (in 2019-21) and GJ 1289 (in 2022-23), respectively. The rotation periods measured with the magnetic field differ from the orbital periods and, in general, stellar activity is not seen in the studied nIR RV time series of both stars. GJ 3378 b detections have not been confirmed by optical RVs and, therefore, they are solely considered a candidate for the present purposes.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"312 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141708536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of electrons on granulation-generated solar chromosphere heating and plasma outflows","authors":"M. Pelekhata, K. Murawski, S. Poedts","doi":"10.1051/0004-6361/202449955","DOIUrl":"https://doi.org/10.1051/0004-6361/202449955","url":null,"abstract":"Context: It is known that the solar atmosphere exhibits a varying degree of ionization through its different layers. The ionization degree directly depends on plasma temperature, i.e., the lower the temperature, the lower the ionization degree. As a result, the plasma in the lower atmospheric layers (the photosphere and the chromosphere) is only partially ionized, which motivates the use of a three-fluid model. \u0000Aims: The paper aims to consider for the first time the influence of electrons on granulation-generated solar chromosphere heating and plasma outflows. We attempt to detect variations in the ion temperature and plasma up- and down-flows. \u0000Methods: We perform $2.5$-D numerical simulations of the generation and evolution of granulation-generated waves, flows, and other granulation-associated phenomena with the adaptation of the JOANNA code. This code solves the simplified three-fluid equations for ions (protons), electrons and neutrals (hydrogen atoms) which are coupled by collision forces. \u0000Results: Electron-neutral and electron-ion collisions provide extra heat in the low chromosphere and enhance plasma outflows in this region. However, this effect is small and can be neglected. \u0000Conclusions: Electrons do not play a major role in solar chromosphere heating and generation of plasma outflows.","PeriodicalId":505693,"journal":{"name":"Astronomy & Astrophysics","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141709580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}