Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-09-15
Astron.Astrophys. 429 (2005) 887-894
Astronomy and Astrophysics
Astrophysics
8 pages. A&A accepted
Scientific paper
10.1051/0004-6361:20041694
Hipparcos parallax measurements of stars in the Pleiades notoriously result in a cluster distance of 118 pc; ~10% shorter than the `classical' results of MS-fitting. In an earlier paper we developed a purely empirical MS-fitting method to address this problem, which produced conflicting results between the (B-V) and (V-I) colour indices, indicating that the cluster's photometric metallicity is substantially lower than its (~solar) spectroscopic metallicity. We were able to reconcile the discrepancy by assuming [Fe/H]=-0.4 (as indicated from (B-V)/(V-I) colour-colour plots), and the distance moduli obtained from the 2 indices were in agreement with the Hipparcos result, within the 1sig errors. With the release of the 2MASS All Sky Catalogue, we now apply our MS-fitting method to the Pleiades using the infrared colours, in order to test the plausibility of our earlier result. Fitting in the V/(V-K) and K/(J-K) colour planes, we find that assuming a subsolar metallicity does not produce distances in agreement with the (B-V) and (V-I) results. However the infrared plus (V-I) distances are in mutual agreement when adopting the spectroscopic metallicity. By considering only stars with Mv<=6, the infrared and optical colour indices all yield consistent distances using the spectroscopic [Fe/H]. The concordant distances thus obtained from the (B-V), (V-I), (V-K) and (J-K) indices yield a mean of 133.8+/-3 pc, in excellent agreement with the pre-Hipparcos MS-fitting results, and the most recent determinations from other methods. We conclude that there are two distinct issues affecting the Pleiades: the Hipparcos parallax is in error by ~10%, as previously claimed; the (B-V) colours of the lower MS are anomalous, and we caution against their use for MS-fitting to the Pleiades and similarly young open clusters. (Abridged)
Groenewegen Martin A. T.
Percival Susan M.
Salaris Maurizio
No associations
LandOfFree
The distance to the Pleiades: Main sequence fitting in the near infrared does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The distance to the Pleiades: Main sequence fitting in the near infrared, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The distance to the Pleiades: Main sequence fitting in the near infrared will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-620745