Praesepe (NGC 2632) and its tidal tails
Abstract
Aims: Within a 400 pc sphere around the Sun, we search for Praesepe's tidal tails in the Gaia Data Release 2 (DR2) data set.
Methods: We used a modified convergent-point method to find stars with space velocities close to the space velocity of the Praesepe cluster.
Results: We find a clear indication for the existence of Praesepe's tidal tails, both extending up to 165 pc from the centre of the cluster. A total of 1393 stars populate the cluster and its tails, giving a total mass of 794 M⊙. We determined a tidal radius of 10.77 pc for the cluster and a tidal mass of 483 M⊙. The corresponding half-mass radius is 4.8 pc. We also found a clear indication for mass segregation in the cluster. The tidal tails outside 2 tidal radii are populated by 389 stars. The total contamination of our sample by field stars lies between 50 and 100 stars or 3.6-7.2%. We used an astrometrically and photometrically clean subsample of Gaia DR2, which makes our Praesepe sample incomplete beyond MG ≈ 12.0 mag; this corresponds to about 0.25 M⊙. A comparison with an N-body model of the cluster and its tails shows remarkably good coincidence. Three new white dwarfs are found in the tails.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 2019
- DOI:
- 10.1051/0004-6361/201935502
- arXiv:
- arXiv:1903.08610
- Bibcode:
- 2019A&A...627A...4R
- Keywords:
-
- open clusters and associations;
- individual: Praesepe;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 6 pages, 5 figures. Accepted by Astronomy and Astrophysics