J/A+A/440/305 Fundamental parameters of fast-rotating B stars (Fremat+, 2005)
Effects of gravitational darkening on the determination of fundamental
parameters in fast-rotating B-type stars.
Fremat Y., Zorec J., Hubert A.-M., Floquet M.
<Astron. Astrophys., 440, 305-320 (2005)>
=2005A&A...440..305F 2005A&A...440..305F
ADC_Keywords: Models, atmosphere ; Stars, early-type
Keywords: stars: abundances - stars: atmospheres - stars: early-type -
stars: emission-line, Be - stars: fundamental parameters
Abstract:
In this paper we develop a calculation code to account for the effects
carried by fast rotation on the observed spectra of early-type stars.
Stars are assumed to be in rigid rotation, and the grid of
plane-parallel model atmospheres used to represent the gravitational
darkening are calculated by means of a non-LTE approach. Attention is
paid to the relation between the apparent and parent non-rotating
counterpart stellar fundamental parameters and apparent, and true
Vsini parameters as a function of the rotation rate Omega/Omegac,
stellar mass, and inclination angle. It is shown that omitting of
gravitational darkening in the analysis of chemical abundances of CNO
elements can produce systematic overestimation or underestimation,
depending on the lines used, rotational rate, and inclination angle.
Description:
The reference model parameters proper to calculating FASTROT
rotationally modified synthetic spectra, as well as those obtained by
fitting the rotationally distorted spectra with them, are hereafter
called parent non-rotating counterpart (pnrc) fundamental parameters,
while vsini will represent the true projected rotation velocity of the
star. Conversely, we call apparent fundamental parameters (e.g. TeffA,
loggA and vsiniA), those derived by fitting the GRIDB spectral lines
with synthetic spectra issued from classical plane-parallel model
atmospheres.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 80 129 Apparent and parent non-rotating counterpart (pnrc)
fundamental parameters of the studied stars
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number of the star
8- 12 I5 K TeffA Apparent effective temperature
14- 16 I3 K e_TeffA rms uncertainty on TeffA
18- 22 F5.3 [cm/s2] loggA Apparent surface gravity
24- 28 F5.3 [cm/s2] e_loggA rms uncertainty on loggA
30- 32 I3 km/s vsiniA Apparent rotational velocity
34- 35 I2 km/s e_vsiniA rms uncertainty on vsiniA
37- 41 I5 K Teff Effective temperature, pnrc parameter
43- 45 I3 K e_Teff rms uncertainty on Teff
47- 51 F5.3 [cm/s2] logg Surface gravity, pnrc parameter
53- 57 F5.3 [cm/s2] e_logg rms uncertainty on logg
59- 61 I3 km/s vsini Corrected rotational velocity (pnrc) (1)
63- 64 I2 km/s e_vsini rms uncertainty on vsini
66- 68 I3 km/s Vc Critical equatorial velocity (pnrc) (1)
70- 71 I2 km/s e_Vc rms uncertainty on Vc
73- 76 F4.1 deg incl Estimated inclination angle (pnrc) (1)
78- 80 F3.1 deg e_incl rms uncertainty on incl
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Note (1): pnrc = parent non-rotating counterpart
(see the "Description" section above)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Jul-2006