Atmospheric velocity fields in tepid main sequence stars
نویسندگان
چکیده
منابع مشابه
Detection of atmospheric velocity fields in A-type stars
High signal-to-noise spectra with spectral resolution of more than 105 have been obtained of one normal B9.5V, one normal A1V, two Am stars, and two HgMn B stars having v sin i less than 6 km s−1. These spectra are modeled with LTE line profile synthesis to test the extent to which the spectrum of each star can be modeled correctly with a single set of parameters Te, log g, chemical abundances,...
متن کاملCircumstellar Disks in pre-Main–Sequence Stars
This review covers the properties of disks around pre-main– sequence stars. It is at this time in the evolution that planets form, and it is important to understand the properties of these disks to understand planet formation. I discuss disk shapes, masses and temperatures, the properties of the host stars, disk lifetimes and dissipation processes. Finally, evidence of grain growth during pre-m...
متن کاملMagnetic flaring in pre-main sequence stars
Observations of nearby star forming clouds with imaging Xray telescopes have revealed that X-ray emission is elevated 10 − 10 above main sequence levels in low-mass pre-main sequence (PMS) stars. The variability and spectral X-ray evidence, together with circularly polarized radio continuum flares seen in a few cases, strongly argues for an origin in magnetic reconnection flares. These high lev...
متن کاملCoronal Structure of Pre-Main Sequence Stars
The study of pre-main sequence stellar coronae is undertaken in many different wavelength regimes, with apparently conflicting results. X-ray studies of T Tauri stars suggest the presence of loops with a range of sizes ranging from less than a stellar radius to 10 stellar radii. Some of these stars show a clear rotational modulation in X-rays, but many do not and indeed the nature of this emiss...
متن کاملEntropy Production of Main-Sequence Stars
The entropy production (inside the volume bounded by a photosphere) of main-sequence stars is calculated based on B–V photometry data. The entropy-production distribution function and the dependences of entropy production on temperature and luminosity are obtained for these stars for the first time. A very small range of variation of specific (per volume) entropy production discovered for main-...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2009
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/200912083