Praesepe and the seven white dwarfs
Abstract
We report the discovery, from our preliminary survey of the Praesepe open cluster, of two new spectroscopically confirmed white dwarf candidate members. We derive the effective temperatures and surface gravities of WD0837+218 and WD0837+185 (LB5959) to be 17845+555-565K and log g = 8.48+0.07-0.08 and 14170+1380-1590K and log g = 8.46+0.15-0.16, respectively. Using theoretical evolutionary tracks we estimate the masses and cooling ages of these white dwarfs to be 0.92 +/- 0.05Msolar and 280+40-30 Myr and 0.90 +/- 0.10 Msolar and 500+170-100 Myr, respectively. Adopting reasonable values for the cluster age we infer the progenitors of WD0837+218 and WD0837+185 had masses of 2.6 <=M<=McritMsolar and 2.4 <=M<= 3.5Msolar, respectively, where Mcrit is the maximum mass of a white dwarf progenitor. We briefly discuss these findings in the context of the observed deficit of white dwarfs in open clusters and the initial mass-final mass relationship.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 2004
- DOI:
- 10.1111/j.1365-2966.2004.08522.x
- arXiv:
- arXiv:astro-ph/0410529
- Bibcode:
- 2004MNRAS.355L..39D
- Keywords:
-
- white dwarfs;
- open clusters and associations: individual: Praesepe;
- Astrophysics
- E-Print:
- Accepted for publication in MNRAS