The Sirius Supercluster in FK5 (original) (raw)

ADS

Abstract

Fifty-five stars in the FK5 or with PPM(H) quality proper motions are discussed as members of the Sirius supercluster. The convergent point of the supercluster motion is (A, D) = (20.55h -38.1 deg) and the space velocity is V(T) = 18.6 + 0.005X km/s, where X is the radial distance of the members from the sun. The member stars indicate (Fe/H) Hyades - (Fe/H) Sirius = 0.18 dex from both photometric and spectroscopic evidence. The bulk of the supercluster members fall into two age groups, 6.3 x 10 exp 8 and 10 exp 9 yr on the basis of models with convective overshoot. The available observations of chromospheric activity in Mg II (h and k) are quantized into three well-defined groups for both Sirius supercluster and Hyades cluster dwarfs. For 20 supercluster members with cluster parallax greater than 0.03 arcsec the ratio of pi(cluster)/pi(trigonometric) = 0.95 +/- 0.20(sigma).

Publication:

The Astronomical Journal

Pub Date:

October 1992

DOI:

10.1086/116334

Bibcode:

1992AJ....104.1493E

Keywords: