NOAO > Library > NOAO Preprint Series > Preprint 901
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NOAO > Library > NOAO Preprint Series > Preprint 901 |
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Author(s): Kinman, T., and Castelli, F.
Title: The Determination of T_{eff} for
Metal-Poor A-type Stars Using V
and 2MASS J, H and K Magnitudes
Abstract:
Effective temperatures (T_{eff}) 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 T_{eff} of faint blue
halo stars (V \simlt 15) whose temperatures are now
usually deduced from (B − V)_0. Transformations (adapted from Carpenter,
2001b) are used to change colours derived from the
2MASS data to the Johnson system. T_{eff} is then derived from these colours
using an updated Kurucz model. Tables are given
to derive T_{eff} as a function of (V − J)_0, (V − H)_0 and (V
− K)_0 for a variety of metallicities and log g 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 \leq V \leq 15 and T_{eff} in the range 6500 to 9500 K;
systematic differences are \sim 100 K. An exception is the
sample of BHB stars observed by Wilhelm et al. (1999) whose T_{eff} are
significantly cooler than those we derive by an amount
that increases with increasing temperature.
Date Received:
July 22, 2002
Publication Info:
Astron. & Astrophys. 391:1039-1052
Downloadable version (6961 Kb PDF)
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NOAO > Library > NOAO Preprint Series > Preprint 901 |
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