- ID:
- ivo://CDS.VizieR/J/A+A/556/A15
- Title:
- Effective temperature scale of M dwarfs
- Short Name:
- J/A+A/556/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Despite their large number in the Galaxy, M dwarfs remain elusive objects and the modeling of their photosphere has long remained a challenge (molecular opacities, dust cloud formation). Our objectives are to validate the BT-Settl model atmospheres, update the M dwarf T_eff_-spectral type relation, and find the atmospheric parameters of the stars in our sample. We compare two samples of optical spectra covering the whole M dwarf sequence with the most recent BT-Settl synthetic spectra and use a {chi}^2^ minimization technique to determine Teff. The first sample consists of 97 low-resolution spectra obtained with New Technology Telescope (NTT) at La Silla Observatory. The second sample contains 55 medium-resolution spectra obtained at the Siding Spring Observatory (SSO). The spectral typing is realized by comparison with already classified M dwarfs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/130/215
- Title:
- Effective temperatures of Ap stars
- Short Name:
- J/A+AS/130/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new method of determination of the effective temperatures of Ap stars is proposed. The method is based on the fact that the slopes of the energy distribution in the Balmer continuum near the Balmer jump for "normal" main sequence stars and Ap stars with the same effective temperature are identical. The effective temperature calibration is based on a sample of main sequence stars with well known temperatures (Sokolov, 1995, Cat. <J/A+AS/110/553>).
- ID:
- ivo://CDS.VizieR/J/A+A/501/297
- Title:
- Effective temperatures of B Supergiants
- Short Name:
- J/A+A/501/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. We aim to obtain a new calibration of the Teff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent.
- ID:
- ivo://CDS.VizieR/J/A+A/369/178
- Title:
- Effective temperatures of carbon-rich stars
- Short Name:
- J/A+A/369/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 10 is the full version of Table A1 given in Appendix. There are 441 entries corresponding to 441 spectral energy distributions (SEDs) of 406 carbon stars and related objects studied in Papers I (<J/A+A/321/236>, II (<J/A+A/342/773> and III (<J/A+A/344/263>) (photometric group G in column 3 and extinction A(J) at J-filter in column 4). Two estimates of the effective temperature (Sect. 12) from the SED (calibrated color indices) and bolometric flux (integrated flux: 0.36 to 100{mu}m) are given in columns 5 and 6 respectively, together with the adopted mean value in column 7. Also given in column 8, the apparent bolometric magnitude of the SED/Star, and in column 9 as "remarks", the variation phase information whenever available, the detection of circumstellar extinction and/or emission with associated mbol2 in a few case (see Sect. 13).
- ID:
- ivo://CDS.VizieR/J/other/BSAO/38.152
- Title:
- Effective temperatures of CP stars
- Short Name:
- J/other/BSAO/38.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new list is presented of effective temperatures estimated for about 700 chemically peculiar stars from the photometric parameters, calibrated with the temperatures determined by Shallis Blackwell (Blackwell et al., 1980A&A....82..249B) method from the total flux of the energy emitted by the stars.
- ID:
- ivo://CDS.VizieR/J/A+A/429/235
- Title:
- Effective temperatures of 119 C-rich giants
- Short Name:
- J/A+A/429/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass loss rates, expansion velocities and dust-to-gas density ratios from millimetric observations of 119 carbon-rich giants are compared, as functions of stellar parameters, to the predictions of recent hydrodynamical models. Distances and luminosities previously estimated from HIPPARCOS data, masses from pulsations and C/O abundance ratios from spectroscopy, and effective temperatures from a new homogeneous scale, are used.
- ID:
- ivo://CDS.VizieR/J/MNRAS/371/879
- Title:
- Effective temperatures of 215 FGK giants
- Short Name:
- J/MNRAS/371/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precise effective temperatures (Teff) of 215 FGK giants determined using the method of line-depth ratios. For each star, we have measured the line depths and equivalent widths of a large number of spectral lines of low and high excitation potentials and established ~100 relations between Teff and their ratios. Starting with an initial value Teff, the relations are then self-calibrated by an iterative process. Our final estimates have been compared with very accurate (1 per cent) published temperatures and show a good agreement. Using our calibrations, we derive precise temperatures for 215 giants with near-solar metallicity, from high-resolution (R=42000) and high signal-to-noise ratio (S/N=100250) echelle spectra, obtained with the ELODIE spectrometer at the Observatoire de Haute Provence (OHP).
- ID:
- ivo://CDS.VizieR/J/AN/321/277
- Title:
- Effective temperatures of K-M giants
- Short Name:
- J/AN/321/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A high-resolution spectroscopic survey in the 6380-6460{AA} region of 224 slowly-rotating M-K class III giants is presented. Spectral line-depth ratio are calibrated against effective temperature obtained from B-V and V-I color indices in the range 3200-7500K (M6-A9). A table of polynomial coefficients for 12 line-ratio-Teff relations can be used to derive Teff of F-M stars to within 33K (rms), and of early-F and mid-to-late M stars to within 77-106K (rms).
- ID:
- ivo://CDS.VizieR/J/ApJ/879/105
- Title:
- Effective temperatures of low-mass stars
- Short Name:
- J/ApJ/879/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution, near-infrared spectra will be the primary tool for finding and characterizing Earth-like planets around low-mass stars. Yet, the properties of exoplanets cannot be precisely determined without accurate and precise measurements of the host star. Spectra obtained with the Immersion Grating Infrared Spectrometer simultaneously provide diagnostics for most stellar parameters, but the first step in any analysis is the determination of the effective temperature. Here we report the calibration of high-resolution H-band spectra to accurately determine the effective temperature for stars between 4000 and 3000K (~K8-M5) using absorption line-depths of FeI, OH, and Al I. The field star sample used here contains 254 K and M stars with temperatures derived using BT-Settl synthetic spectra. We use 106 stars with precise temperatures in the literature to calibrate our method, with typical errors of about 140K, and systematic uncertainties less than ~120K. For the broadest applicability, we present Teff-line-depth-ratio relationships, which we test on 12 members of the TW Hydrae Association and at spectral resolving powers between ~10000 and 120000. These ratios offer a simple but accurate measure of effective temperatures in cool stars that are distance and reddening independent.
- ID:
- ivo://CDS.VizieR/J/AJ/156/292
- Title:
- Effect of close companions on exoplanetary radii
- Short Name:
- J/AJ/156/292
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding the distribution and occurrence rate of small planets was a fundamental goal of the Kepler transiting exoplanet mission, and could be improved with K2 and Transiting Exoplanet Survey Satellite (TESS). Deriving accurate exoplanetary radii requires accurate measurements of the host star radii and the planetary transit depths, including accounting for any "third light" in the system due to nearby bound companions or background stars. High-resolution imaging of Kepler and K2 planet candidate hosts to detect very close (within ~0.5") background or bound stellar companions has been crucial for both confirming the planetary nature of candidates, and the determination of accurate planetary radii and mean densities. Here we present an investigation of the effect of close companions, both detected and undetected, on the observed (raw count) exoplanet radius distribution. We demonstrate that the recently detected "gap" in the observed radius distribution (also seen in the completeness-corrected distribution) is fairly robust to undetected stellar companions, given that all of the systems in the sample have undergone some kind of vetting with high-resolution imaging. However, while the gap in the observed sample is not erased or shifted, it is partially filled in after accounting for possible undetected stellar companions. These findings have implications for the most likely core composition, and thus formation location, of super-Earth and sub-Neptune planets. Furthermore, we show that without high-resolution imaging of planet candidate host stars, the shape of the observed exoplanet radius distribution will be incorrectly inferred, for both Kepler- and TESS-detected systems.