J/A+A/391/1039 Effective temperature of metal-poor A-type stars (Kinman+, 2002)
The determination of Teff for metal-poor A-type stars using V and
2MASS J, H and K magnitudes
Kinman T., Castelli F.
<Astron. Astrophys. 391, 1039 (2002)>
=2002A&A...391.1039K 2002A&A...391.1039K
ADC_Keywords: Stars, A-type ; Effective temperatures ; Photometry, infrared
Keywords: stars: fundamental parameters (temperatures) -
stars: horizontal-branch
Abstract:
Effective temperatures (Teff) can be determined from (V-J)0,
(V-H)0 and (V-K)0 colours that are derived from 2MASS magnitudes.
This gives another way to estimate the Teff of faint blue halo stars
(V≲15) whose temperatures are now usually deduced from (BV)0_.
Transformations (adapted from Carpenter, 2001AJ....121.2851C 2001AJ....121.2851C) are used
to change colours derived from the 2MASS data to the Johnson system.
Teff is then derived from these colours using an updated Kurucz
model. Tables are given to derive Teff as a function of (V-J)0,
(V-H)0 and (V-K)0 for a variety of metallicities and suitable for
blue horizontal branch and main sequence stars. The temperatures
obtained in this way are compared with those in the recent literature
for various stars with 5≤V≤15 and Teff in the range 6500 to 9500K;
systematic differences are ∼100K. An exception is the sample of BHB
stars observed by Wilhelm et al. (1999, Cat. J/AJ/117/2329) whose
Teff are significantly cooler than those we derive by an amount that
increases with increasing temperature. Description:
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 68 351 Effective temperatures and Johnson-Glass colours
for blue horizontal branch (BHB) stars
table3.dat 93 401 Effective Temperatures and Johnson-Glass colours
for blue metal poor (BMP) stars with logg=4.0 or 4.5
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See also:
B/2mass : The 2MASS database (IPAC/UMass, 2000)
J/AJ/117/2329 : Spectroscopy of hot stars in the halo. III (Wilhelm+, 1999)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 K Teff Effective temperature
7- 12 F6.3 mag (V-J)-1 (V-J) colour index for [Fe/H]=-1.0
14- 19 F6.3 mag (V-H)-1 (V-H) colour index for [Fe/H]=-1.0
21- 26 F6.3 mag (V-K)-1 (V-K) colour index for [Fe/H]=-1.0
28- 33 F6.3 mag (V-J)-1.5 (V-J) colour index for [Fe/H]=-1.5
35- 40 F6.3 mag (V-H)-1.5 (V-H) colour index for [Fe/H]=-1.5
42- 47 F6.3 mag (V-K)-1.5 (V-K) colour index for [Fe/H]=-1.5
49- 54 F6.3 mag (V-J)-2 (V-J) colour index for [Fe/H]=-2.0
56- 61 F6.3 mag (V-H)-2 (V-H) colour index for [Fe/H]=-2.0
63- 68 F6.3 mag (V-K)-2 (V-K) colour index for [Fe/H]=-2.0
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 F3.1 [cm/s2] logg Gravity surface (4.0 or 4.5)
5- 9 I5 K Teff Effective temperature
11- 16 F6.3 mag (V-J)0 (V-J) colour index for [Fe/H]=0.0
18- 23 F6.3 mag (V-H)0 (V-H) colour index for [Fe/H]=0.0
25- 30 F6.3 mag (V-K)0 (V-K) colour index for [Fe/H]=0.0
32- 37 F6.3 mag (V-J)-1 (V-J) colour index for [Fe/H]=-1.0
39- 44 F6.3 mag (V-H)-1 (V-H) colour index for [Fe/H]=-1.0
46- 51 F6.3 mag (V-K)-1 (V-K) colour index for [Fe/H]=-1.0
53- 58 F6.3 mag (V-J)-1.5 (V-J) colour index for [Fe/H]=-1.5
60- 65 F6.3 mag (V-H)-1.5 (V-H) colour index for [Fe/H]=-1.5
67- 72 F6.3 mag (V-K)-1.5 (V-K) colour index for [Fe/H]=-1.5
74- 79 F6.3 mag (V-J)-2 (V-J) colour index for [Fe/H]=-2.0
81- 86 F6.3 mag (V-H)-2 (V-H) colour index for [Fe/H]=-2.0
88- 93 F6.3 mag (V-K)-2 (V-K) colour index for [Fe/H]=-2.0
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Acknowledgements: Tom Kinman
(End) Patricia Bauer [CDS] 23-Jul-2002