Elena Schilbach, Siegfried Roeser
On the basis of the PPMXL catalogue we search for white dwarfs as candidates
for members of the Hyades in a region up to 40 pc from the cluster centre.We
use the proper motions from PPMXL in the convergent point method to determine
probable kinematic members. We cross-match the kinematic candidates with
catalogues containing white dwarfs and, finally, check the kinematic with the
photometric distances for consistency. We find the 10 classical white dwarfs in
the Hyades and determine their individual kinematic distances. Additionally, we
identified 17 new probable (former) Hyades white dwarfs, i.e. white dwarfs
co-moving with the bulk space motion of the Hyades cluster. At present, none of
them can be excluded from membership on the basis of the measured radial
velocities. For another 10 objects, the kinematic and the photometric distances
are discordant which rates them as probable non-members. Among the probable
members, five white dwarfs are in binary systems, three are known, two are new.
There is good indication for an empirical magnitude-distance (from centre)
relation, such that the dimmer white dwarfs are farther away from the cluster
centre than the brighter ones. Our sample is getting incomplete close behind
the centre of the cluster. Follow-up observations are encouraged to
independently confirm the predicted radial velocities and the distances of the
candidates.
View original:
http://arxiv.org/abs/1111.3959
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