- ID:
- ivo://CDS.VizieR/J/A+A/624/A49
- Title:
- Spectra of Earth-like planets around M-dwarfs
- Short Name:
- J/A+A/624/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The characterisation of the atmosphere of exoplanets is one of the main goals of exoplanet science in the coming decades. We investigate the detectability of atmospheric spectral features of Earth-like planets in the habitable zone (HZ) around M dwarfs with the future James Webb Space Telescope (JWST). We used a coupled 1D climate-chemistry-model to simulate the influence of a range of observed and modelled M-dwarf spectra on Earth-like planets. The simulated atmospheres served as input for the calculation of the transmission spectra of the hypothetical planets, using a line-by-line spectral radiative transfer model. To investigate the spectroscopic detectability of absorption bands with JWST we further developed a signal- to-noise ratio (S/N) model and applied it to our transmission spectra. High abundances of methane (CH_4_) and water (H_2_O) in the atmosphere of Earth-like planets around mid to late M dwarfs increase the detectability of the corresponding spectral features compared to early M-dwarf planets. Increased temperatures in the middle atmosphere of mid- to late-type M-dwarf planets expand the atmosphere and further increase the detectability of absorption bands. To detect CH_4_, H_2_O, and carbon dioxide (CO_2_) in the atmosphere of an Earth-like planet around a mid to late M dwarf observing only one transit with JWST could be enough up to a distance of 4pc and less than ten transits up to a distance of 10pc. As a consequence of saturation limits of JWST and less pronounced absorption bands, the detection of spectral features of hypothetical Earth-like planets around most early M dwarfs would require more than ten transits. We identify 276 existing M dwarfs (including GJ 1132, TRAPPIST-1, GJ 1214, and LHS 1140) around which atmospheric absorption features of hypothetical Earth-like planets could be detected by co-adding just a few transits. The TESS satellite will likely find new transiting terrestrial planets within 15pc from the Earth. We show that using transmission spectroscopy, JWST could provide enough precision to be able to partly characterise the atmosphere of TESS findings with an Earth-like composition around mid to late M dwarfs.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/567/A49
- Title:
- Spectra of IPHAS symbiotic stars
- Short Name:
- J/A+A/567/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IPHAS H{alpha} survey provides a rich database to search for emission-line sources in the northern Galactic plane. We are systematically searching for symbiotic stars in the Milky Way using IPHAS. Our final goal, a complete census of this class of objects in the Galaxy, is a fundamental figure for discussing their overall properties and relevance to other classes of stars. Candidate symbiotic stars were selected using a refined combination of IPHAS and 2MASS photometric colours. Optical spectroscopy, together with the analysis of their spectral energy distribution in the IR, were obtained to confirm their nature and determine their main properties.
- ID:
- ivo://CDS.VizieR/III/114
- Title:
- Spectra of Late-Type Standards, 2.0-2.5 Microns
- Short Name:
- III/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a collection of K-band spectra for 26 stars with near-solar abundances, ranging in spectral class from F8 to M7 and in luminosity from dwarfs to supergiants. The spectra cover the wavelength region from 4150 to 4950 /cm and generally exhibit a signal to noise ratio above 400. Five stars here are supergiants, 15 are giants, and six are dwarfs. Data included: observation date, starting wavenumber, wavenumber increment, scale factor of relative intensity, and offset of relative intensity.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/188
- Title:
- Spectra of nearby late K and M Kepler stars
- Short Name:
- J/ApJ/779/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities. We use these revised values to calibrate spectroscopic techniques to infer the fundamental parameters of more distant late-type dwarf stars. We demonstrate that, after masking out poorly modeled regions, the newest version of the PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. We apply methods to late-type hosts of transiting planet candidates in the Kepler field, and calculate effective temperature, radius, mass, and luminosity with typical errors of 57K, 7%, 11%, and 13%, respectively. We find systematic offsets between our values and those from previous analyses of the same stars, which we attribute to differences in atmospheric models utilized for each study. We investigate which of the planets in this sample are likely to orbit in the circumstellar habitable zone. We determine that four candidate planets (KOI 854.01, 1298.02, 1686.01, and 2992.01) are inside of or within 1{sigma} of a conservative definition of the habitable zone, but that several planets identified by previous analyses are not (e.g., KOI 1422.02 and KOI 2626.01). Only one of the four habitable-zone planets is Earth sized, suggesting a downward revision in the occurrence of such planets around M dwarfs. These findings highlight the importance of measuring accurate stellar parameters when deriving parameters of their orbiting planets.
- ID:
- ivo://CDS.VizieR/J/ApJ/535/325
- Title:
- Spectra of normal stars in the J-band
- Short Name:
- J/ApJ/535/325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of J-band spectra for 88 fundamental MK standard stars observed at a resolving power of R~3000. This contribution serves as a companion atlas to the K-band spectra recently published by Wallace & Hinkle (1997, Cat. <J/ApJS/111/445>) and the H-band atlas by Meyer and coworkers. We report data from 7400 to 9550cm^-1^ (1.05-1.34um) for stars of spectral types O7-M6 and luminosity classes I-V as defined in the MK system. In reducing these data, special care has been taken to remove time-variable telluric features of water vapor. We identify atomic and molecular indexes that are both temperature and luminosity sensitive that aid in the classification of stellar spectra in the J band. In addition to being useful in the classification of late-type stars, the J band contains several features of interest in the study of early-type stellar photospheres.
- ID:
- ivo://CDS.VizieR/J/ApJS/111/445
- Title:
- Spectra of normal stars in the K band
- Short Name:
- J/ApJS/111/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An Atlas of 115 medium-resolution K-band (2.0-2.4um) stellar spectra, spanning spectral types O-M and luminosity types I-V, is presented. K-band spectra are also presented for one N- and one J-type carbon star. A time series of spectra is presented for an S-type Mira variable. All the spectra are at a resolution of ~3000 (1.4cm^-1^) and have had the terrestrial absorption removed by dividing a featureless spectrum. The spectra are plotted with the major spectral features identified and are available digitally.
- ID:
- ivo://CDS.VizieR/J/AJ/124/3393
- Title:
- Spectra of normal stars in the L-band
- Short Name:
- J/AJ/124/3393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a brief atlas of L-band (3.3-4.2um) spectra for 42 stars plus the Sun and a sunspot observed at a resolving power of R~3000. This contribution is intended to supplement our previous K-band, H-band, and J-band spectral atlases. The L-band data, which cover some or all of the 2400 to 3000cm^-1^ (3.3-4.2um) region, are mainly for luminous late-type stars. In reducing these data, special care has been taken to remove telluric features, especially water vapor. We identify temperature- and luminosity-sensitive atomic and molecular indices to aid in the classification of stellar spectra in the L band.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/1964
- Title:
- Spectra of three nearby star-forming regions
- Short Name:
- J/ApJ/703/1964
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze samples of Spitzer Infrared Spectrograph spectra of T Tauri stars in the Ophiuchus, Taurus, and Chamaeleon I star-forming regions, whose median ages lie in the <1-2Myr range. The median mid-infrared spectra of objects in these three regions are similar in shape, suggesting, on average, similar disk structures. When normalized to the same stellar luminosity, the medians follow each other closely, implying comparable mid-infrared excess emission from the circumstellar disks. We use the spectral index between 13 and 31um and the equivalent width of the 10um silicate emission feature to identify objects whose disk configuration departs from that of a continuous, optically thick accretion disk. Based on their medians and fraction of evolved disks, T Tauri stars in Taurus and Chamaeleon I are very alike.
- ID:
- ivo://CDS.VizieR/J/AJ/153/46
- Title:
- Spectroscopy of candidate members in Taurus
- Short Name:
- J/AJ/153/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies have found that ~1deg^2^ fields surrounding the stellar aggregates in the Taurus star-forming region exhibit a surplus of solar-mass stars relative to denser clusters like IC 348 and the Orion Nebula Cluster. To test whether this difference reflects mass segregation in Taurus or a variation in the initial mass function, we have performed a survey for members of Taurus across a large field (~40deg^2^) that was imaged by the Sloan Digital Sky Survey (SDSS). We obtained optical and near-infrared spectra of candidate members identified with those images and the Two Micron All Sky Survey, as well as miscellaneous candidates that were selected with several other diagnostics of membership. We have classified 22 of the candidates as new members of Taurus, which includes one of the coolest known members (M9.75). Our updated census of members within the SDSS field shows a surplus of solar-mass stars relative to clusters, although it is less pronounced than in the smaller fields toward the stellar aggregates that were surveyed for previously measured mass functions in Taurus. In addition to spectra of our new members, we include in our study near-IR spectra of roughly half of the known members of Taurus, which are used to refine their spectral types and extinctions. We also present an updated set of near-IR standard spectra for classifying young stars and brown dwarfs at M and L types.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/1536
- Title:
- Spectroscopy of of IC4499 red giants
- Short Name:
- J/MNRAS/411/1536
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocity and metallicity measurements for the far southern Galactic globular cluster IC 4499. We selected several hundred target red giant stars in and around the cluster from the 2MASS point source catalogue, and obtained spectra at the near-infrared calcium triplet using the AAOmega spectrograph. Observations of giants in globular clusters M4, M22 and M68 were taken to provide radial velocity and metallicity comparison objects.
