Related papers: Stellar classification of CoRoT targets
We establish an empirical effective temperature calibration of main sequence, luminosity class V to III B-type stars for the Delta a photometric system which was originally developed to detect magnetic chemically peculiar objects of the…
We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equators and are all fainter than r ~ 16.5 mag.…
Hot Jupiters with brightness temperatures > ~2000K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an…
We analyse medium-resolution spectra (R\sim 18000) of 19 late type dwarfs in order to determine vsini-s using synthetic rather than observational template spectra. For this purpose observational data around 2.2 $\mu$m of stars with spectral…
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…
Aims: Low-resolution optical spectroscopic observations for 78 very low-mass star and brown dwarf candidates that have been photometrically selected using the DENIS survey point source catalogue. Methods: Spectral types are derived for them…
We aimed to assess the accuracy of the Gaia teff and logg estimates as derived with current models and observations. We assessed the validity of several inference techniques for deriving the physical parameters of ultra-cool dwarf stars. We…
We present an analysis of the intrinsic colors and temperatures of 5-30 Myr old pre-main sequence (pre-MS) stars using the F0 through M9 type members of nearby, negligibly reddened groups: Eta Cha cluster, TW Hydra Association, Beta Pic…
Measuring starspot temperatures is crucial for understanding stellar magnetic activity, as it affects stellar brightness variations, influences exoplanet transit measurements, and provides constraints on the physical conditions and energy…
Recent massive sky surveys in different bandwidths are providing new opportunities to modern astronomy. The Virtual Observatory (VO) represents the adequate framework to handle the huge amount of information available and filter out data…
We report the discovery of twenty-one hitherto unknown bright southern ultracool dwarfs with spectral types in the range M7 to L5.5, together with new observations of a further three late M dwarfs previously confirmed. Three more objects…
The number and distribution of dwarf satellite galaxies remain a critical test of cold dark matter-dominated structure formation on small scales. Until recently, observational information about galaxy formation on these scales has been…
We report techniques and results of a Palomar 200-inch (5 m) adaptive optics imaging survey of sub-stellar companions to solar-type stars. The survey consists of Ks coronagraphic observations of 21 FGK dwarfs out to 20 pc (median distance…
We set out to determine stellar labels from low-resolution survey spectra of hot, OBA stars with effective temperature (Teff) higher than 7500K. This fills a gap in the scientific analysis of large spectroscopic stellar surveys such as…
Brown dwarfs are failed stars with very low mass (13 to 75 $M_J$), and an effective temperature lower than 2500 K. Thus, they play a key role in understanding the gap in the mass function between stars and planets. However, due to their…
We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3.5-8 micron photometry for 19 cool white dwarfs with 5000K < Teff < 9000K. We perform a detailed model atmosphere…
We use star counts from 13 deep HST fields imaged with the {\it Wide Field Camera - 2} in order to constrain the amount of dark matter in the Galaxy that can be in the form of low-mass main sequence stars or white-dwarfs. Based on the…
We present an atlas of moderate resolution ($\lambda/\Delta\lambda\sim$1380) 2.15~\micron\ to 2.39~\micron\ spectra of 33 luminosity class V stars of spectral type F3 to M6 in the MK classification system. We find that the equivalent widths…
We present a quantitative and homogeneous analysis of the broadband multicolor photometric data sets gathered so far on rapidly pulsating hot B subdwarf stars. This concerns seven distinct data sets related to six different stars. Our…
Cool stars, such as M giants, can only be analysed in the near-infrared (NIR) regime due to the ubiquitous TiO features in optical spectra of stars with Teff < 4000 K. In dust obscured regions, like the inner bulge and Galactic Center, the…