This paper presents a method to determine effective temperatures, angular semi-diameters and bolometric corrections for population I and II FGK type stars based on V and 2MASS IR photometry. Accurate calibration is accomplished by using a sample of solar analogues, whose average temperature is assumed to be equal to the solar effective temperature of 5777K.
Effective temperatures for 420 stars with spectral types between A0 and K3, and luminosity classes between II and V, selected for a flux calibration of the Infrared Space Observatory, ISO, have been determined using the Infrared Flux Method (IRFM). The determinations are based on narrow and wide band photometric data obtained for this purpose, and take into account previously published narrow-band measures of temperature.
We present a catalog of revised effective temperatures for stars observed in long-cadence mode in the Kepler Input Catalog (KIC). We use Sloan Digital Sky Survey (SDSS) griz filters tied to the fundamental temperature scale. Polynomials for griz color-temperature relations are presented, along with correction terms for surface gravity effects, metallicity, and statistical corrections for binary companions or blending. We compare our temperature scale to the published infrared flux method (IRFM) scale for V_T_JKs in both open clusters and the Kepler fields. We find good agreement overall, with some deviations between (J-Ks)-based temperatures from the IRFM and both SDSS filter and other diagnostic IRFM color-temperature relationships above 6000K. For field dwarfs, we find a mean shift toward hotter temperatures relative to the KIC, of order 215K, in the regime where the IRFM scale is well defined (4000K to 6500K). This change is of comparable magnitude in both color systems and in spectroscopy for stars with T_eff_ below 6000K. Systematic differences between temperature estimators appear for hotter stars, and we define corrections to put the SDSS temperatures on the IRFM scale for them. When the theoretical dependence on gravity is accounted for, we find a similar temperature scale offset between the fundamental and KIC scales for giants. We demonstrate that statistical corrections to color-based temperatures from binaries are significant. Typical errors, mostly from uncertainties in extinction, are of order 100K.
The infrared flux method (IRFM) has been applied to a sample of 135 dwarf and 36 giant stars covering the following regions of the atmospheric parameter space: (1) the metal-rich ([Fe/H]>~0) end (consisting mostly of planet-hosting stars), (2) the cool (Teff<~5000K) metal-poor (-1<~[Fe/H]<~-3) dwarf region, and (3) the very metal-poor ([Fe/H]<~-2.5) end.
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.
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>).
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.
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).
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.
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.