- ID:
- ivo://CDS.VizieR/J/A+A/572/A50
- Title:
- J0113+31 light + velocity curves
- Short Name:
- J/A+A/572/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the fundamental properties of 1SWASP J011351.29+314909.7 (J0113+31), a metal-poor (-0.40+/-0.04dex), eclipsing binary in an eccentric orbit (~0.3) with an orbital period of 14.277d. Eclipsing M dwarfs that orbit solar-type stars (EBLMs), like J0113+31, have been identified from their light curves and follow-up spectroscopy in the course of the WASP transiting planet search. We present the analysis of the first binary of the EBLM sample for which masses, radii and temperatures of both components are derived. The primary component with a mass of 0.945+/-0.045M_{sun}_ has a large radius (1.378+/-0.058R_{sun}_) indicating that the system is quite old, ~9.5Gyr. The M-dwarf secondary mass of 0.186+/-0.010M_{sun}_ and radius of 0.209+/-0.011R_{sun}_ are fully consistent with stellar evolutionary models. However, from the near-infrared secondary eclipse light curve, the M dwarf is found to have an effective temperature of 3922+/-42K, which is ~600K hotter than predicted by theoretical models. We present the WASP light curve, the optical follow-up light curves, the near-infrared light curve of the secondary eclipse, and the radial velocity measurements of J0113+31.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/159/18
- Title:
- Jovian-type planets around M dwarfs with MIRI/JWST
- Short Name:
- J/AJ/159/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The upcoming launch of the James Webb Space Telescope (JWST) will dramatically increase our understanding of exoplanets, particularly through direct imaging. Microlensing and radial velocity surveys indicate that some M dwarfs host long-period giant planets. Some of these planets will likely be just a few parsecs away and a few astronomical units from their host stars, a parameter space that cannot be probed by existing high-contrast imagers. We studied whether the coronagraphs on the Mid-infrared Instrument on JWST can detect Jovian-type planets around nearby M dwarfs. For a sample of 27 very nearby M dwarfs, we simulated a sample of Saturn-Jupiter-mass planets with three atmospheric configurations and three orbital separations, observed in three different filters. We found that the f1550c 15.5 {mu}m filter is best suited for detecting Jupiter-like planets. Jupiter-like planets with patchy cloud cover, 2 au from their star, are detectable at 15.5 {mu}m around 14 stars in our sample, while Jupiters with clearer atmospheres are detectable around all stars in the sample. Saturns were most detectable at 10.65 and 11.4 {mu}m (f1065c and f1140c filters), but only with cloud-free atmospheres and within 3 pc (six stars). Surveying all 27 stars would take <170 hr of JWST integration time, or just a few hours for a shorter survey of the most favorable targets. There is one potentially detectable known planet in our sample: GJ 832 b. Observations aimed at detecting this planet should occur in 2024-2026, when the planet is maximally separated from the star.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/93
- Title:
- K-band spectra for 133 nearby M dwarfs
- Short Name:
- J/ApJ/748/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present K-band spectra for 133 nearby (d < 33 pc) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these spectra, we measure equivalent widths of the Ca and Na lines, and a spectral index quantifying the absorption due to H_2_O opacity (the H_2_O-K2 index). Using empirical spectral type standards and synthetic models, we calibrate the H_2_O-K2 index as an indicator of an M dwarf's spectral type and effective temperature. We also present a revised relationship that estimates the [Fe/H] and [M/H] metallicities of M dwarfs from their Na I, Ca I, and H_2_O-K2 measurements. Comparisons to model atmosphere provide a qualitative validation of our approach, but also reveal an overall offset between the atomic line strengths predicted by models as compared to actual observations. Our metallicity estimates also reproduce expected correlations with Galactic space motions and H{alpha} emission line strengths, and return statistically identical metallicities for M dwarfs within a common multiple system. Finally, we find systematic residuals between our H_2_O-based spectral types and those derived from optical spectral features with previously known sensitivity to stellar metallicity, such as TiO, and identify the CaH1 index as a promising optical index for diagnosing the metallicities of near-solar M dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A125
- Title:
- KI diagnostic capabilities for M dwarfs
- Short Name:
- J/A+A/657/A125
- Date:
- 21 Mar 2022 09:37:41
- Publisher:
- CDS
- Description:
- The strong KI doublet near 7700{AA} and another doublet near 12500{AA} are studied in a sample of 324 M dwarfs using CARMENES spectra. For the optical doublet we use only the red line, since the blue line is often contaminated by telluric correction artefacts. Both doublets have a dominant photospheric component in inactive stars and can be used as tracers of effective temperature and gravity. For M dwarfs later than M5.0V the optical doublet lines develop an emission core. The line is often correlated to H{alpha} for stars with H{alpha} in emission and anticorrelated for stars with H{alpha} in absorption. The near-infrared doublet lines very rarely show correlation/anti-correlation to H{alpha}.
- ID:
- ivo://CDS.VizieR/J/AJ/153/92
- Title:
- Late-Type Extension to MoVeRS (LaTE-MoVeRS)
- Short Name:
- J/AJ/153/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Late-Type Extension to the Motion Verified Red Stars (LaTE-MoVeRS) catalog, containing 46,463 photometric late-type (>M5) dwarfs within the Sloan Digital Sky Survey (SDSS) footprint. Proper motions were computed for objects combining astrometry from the SDSS Data Release 12 (DR12), the Two-micron All-Sky Survey (2MASS) Point Source Catalog, and the Wide-field Infrared Survey Explorer (WISE) AllWISE data sets. LaTE-MoVeRS objects were required to have significant proper motion . Using the LaTE-MoVeRS sample and Gaia Data Release 1, we estimate Gaia will be ~64% complete for very low-mass objects (>M5) in comparison to the combined SDSS+2MASS+WISE data set (i<21.3). We computed photometric distances and estimated stellar effective temperatures for the LaTE-MoVeRS catalog. The majority of the dwarfs in the sample have distances <150pc and T<3000K. Thirteen objects that have not been previously identified as nearby eff objects were identified within LaTE-MoVeRS with estimated photometric distances within 25pc. We also identified one new object that has not been previously identified with a large amount of excess mid-infrared flux (2MASS J11151597+1937266). This object appears to be an L2{gamma} at ~50pc showing spectroscopic signs of a flaring event (e.g., strong hydrogen Balmer emission lines). This object does not exhibit kinematics similar to any known kinematic association. The LaTE-MoVeRS catalog is available through SDSS CasJobs and VizieR.
- ID:
- ivo://CDS.VizieR/J/MNRAS/400/1945
- Title:
- Light curves of 261 nearby pulsating M giants
- Short Name:
- J/MNRAS/400/1945
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 5.5-yr CCD photometric campaign that monitored 261 bright, southern, semiregular variables (SRVs) with relatively precise Hipparcos parallaxes. The data are supplemented with independent photoelectric observations of 34 of the brightest stars, including 11 that were not part of the CCD survey, and a previously unpublished long time- series of VZ Cam. Pulsation periods and amplitudes are established for 247 of these stars, the majority of which have not been determined before. All M giants with sufficient observations for period determination are found to be variable, with 87 per cent of the sample (at a signal-to-noise ratio of >=7.5) exhibiting multiperiodic behaviour. The period ratios of local SRVs are in excellent agreement with those in the Large Magellanic Cloud. Apparent K-band magnitudes are extracted from multiple near-infrared catalogues and analysed to determine the most reliable values. We review the effects of interstellar and circumstellar extinction and calculate absolute K-band magnitudes using revised Hipparcos parallaxes.
- ID:
- ivo://CDS.VizieR/J/AJ/154/14
- Title:
- Low-mass stars in 25 Ori group and Orion OB1a
- Short Name:
- J/AJ/154/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Orion OB1a sub-association is a rich low-mass star (LMS) region. Previous spectroscopic studies have confirmed 160 LMSs in the 25 Orionis stellar group (25 Ori), which is the most prominent overdensity of Orion OB1a. Nonetheless, the current census of the 25 Ori members is estimated to be lower than 50% complete, leaving a large number of members to be still confirmed. We retrieved 172 low-resolution stellar spectra in Orion OB1a observed as ancillary science in the SDSS-III/BOSS survey, for which we classified their spectral types and determined physical parameters. To determine memberships, we analyzed the H{alpha} emission, LiI{lambda}6708 absorption, and NaI{lambda}{lambda}8183,8195 absorption as youth indicators in stars classified as M type. We report 50 new LMSs spread across the 25 Orionis, ASCC18, and ASCC20 stellar groups with spectral types from M0 to M6, corresponding to a mass range of 0.10{<=}m/M_{Sun}_{<=}0.58. This represents an increase of 50% in the number of known LMSs in the area and a net increase of 20% in the number of 25 Ori members in this mass range. Using parallax values from the Gaia DR1 catalog, we estimated the distances to these three stellar groups and found that they are all co-distant, at 338+/-66pc. We analyzed the spectral energy distributions of these LMSs and classified their disks into evolutionary classes. Using H-R diagrams, we found a suggestion that 25 Ori could be slightly older than the other two observed groups in Orion OB1a.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A116
- Title:
- LSPM J2116+0234 and GJ 686 radial velocities
- Short Name:
- J/A+A/627/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although M dwarfs are known for high levels of stellar activity, they are ideal targets for the search of low-mass exoplanets with the radial velocity (RV) method. We report the discovery of a planetary-mass companion around LSPM J2116+0234 (M3.0 V) and confirm the existence of a planet orbiting GJ 686 (BD+18 3421; M1.0 V). The discovery of the planet around LSPM J2116+0234 is based on CARMENES RV observations in the visual and near-infrared channels. We confirm the planet orbiting around GJ 686 by analyzing the RV data spanning over two decades of observations from CARMENES VIS, HARPS-N, HARPS, and HIRES. We find planetary signals at 14.44 and 15.53d in the RV data for LSPM J2116+0234 and GJ 686, respectively. Additionally, the RV, photometric time series, and various spectroscopic indicators show hints of variations of 42 d for LSPM J2116+0234 and 37 d for GJ 686, which we attribute to the stellar rotation periods. The orbital parameters of the planets are modeled with Keplerian fits together with correlated noise from the stellar activity. A mini-Neptune with a minimum mass of 11.8M_{Earth}_ orbits LSPM J2116+0234 producing a RV semi- amplitude of 6.19m/s, while a super-Earth of mass 6.6M_{Earth}_ orbits GJ 686 and produces a RV semi-amplitude of 3.0m/s. Both LSPM J2116+0234 and GJ 686 have planetary companions populating the regime of exoplanets with masses lower than 15M_{Earth}_ and orbital periods <20d.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A111
- Title:
- L 98-59 (TOI 175) HARPS observations
- Short Name:
- J/A+A/629/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- L 98-59 (TIC 307210830, TOI-175) is a nearby M3 dwarf around which TESS revealed three small transiting planets (0.80, 1.35, 1.57 Earth radii) in a compact configuration with orbital periods shorter than 7.5 days. Here we aim to measure the masses of the known transiting planets in this system using precise radial velocity (RV) measurements taken with the HARPS spectrograph. We considered both trained and untrained Gaussian process regression models of stellar activity, which are modeled simultaneously with the planetary signals. Our RV analysis was then supplemented with dynamical simulations to provide strong constraints on the planets' orbital eccentricities by requiring long-term stability. We measure the planet masses of the two outermost planets to be 2.42+/-0.35 and 2.31+/-0.46 Earth masses, which confirms the bulk terrestrial composition of the former and eludes to a significant radius fraction in an extended gaseous envelope for the latter. We are able to place an upper limit on the mass of the smallest, innermost planet of <1.01 Earth masses with 95% confidence. Our RV plus dynamical stability analysis places strong constraints on the orbital eccentricities and reveals that each planet's orbit likely has e<0.1. L 98-59 is likely a compact system of two rocky planets plus a third outer planet with a lower bulk density possibly indicative of the planet having retained a modest atmosphere. The system offers a unique laboratory for studies of planet formation, dynamical stability, and comparative atmospheric planetology as the two outer planets are attractive targets for atmospheric characterization through transmission spectroscopy. Continued RV monitoring will help refine the characterization of the innermost planet and potentially reveal additional planets in the system at wider separations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/545
- Title:
- Magnetic field and velocity of early M dwarfs
- Short Name:
- J/MNRAS/390/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here additional results of a spectropolarimetric survey of a small sample of stars ranging from spectral type M0 to M8 aimed at investigating observationally how dynamo processes operate in stars on both sides of the full convection threshold (spectral type M4). The present paper focuses on early M stars (M0-M3), that is above the full convection threshold. Applying tomographic imaging techniques to time series of rotationally modulated circularly polarized profiles collected with the NARVAL spectropolarimeter, we determine the rotation period and reconstruct the large-scale magnetic topologies of six early M dwarfs. We find that early-M stars preferentially host large-scale fields with dominantly toroidal and non-axisymmetric poloidal configurations, along with significant differential rotation (and long-term variability); only the lowest-mass star of our subsample is found to host an almost fully poloidal, mainly axisymmetric large-scale field resembling those found in mid-M dwarfs.
