Main-sequence fitting distance to the σ Ori cluster

被引：63

作者：

Sherry, W. H. ^{[1
]}

Walter, F. M. ^{[2
]}

Wolk, S. J. ^{[3
]}

Adams, N. R. ^{[3
]}

机构：

[1] Natl Solar Observ, Tucson, AZ 85719 USA

[2] SUNY Stony Brook, Stony Brook, NY 11790 USA

[3] Ctr Astrophys, Cambridge, MA 02138 USA

来源：

ASTRONOMICAL JOURNAL | 2008年 / 135卷 / 04期

关键词：

open clusters and associations : general; stars : individual (sigma Ori);

D O I：

10.1088/0004-6256/135/4/1616

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The sigma Ori cluster is an unbound aggregate of a few hundred young, low-mass stars centered on the multiple system sigma Ori. This cluster is of great interest because it is at an age when roughly half of the stars have lost their protoplanetary disks, and the cluster has a very large population of brown dwarfs. One of the largest sources of uncertainty in the properties of the cluster is that the distance is not well known. The directly measured Hipparcos distance to sigma Ori AB is 350(-90)(+120) pc. On the other hand, the distance to the Orion OB1b subgroup (of which sigma Ori is thought to be a member), 473 +/- 40 pc, is far better determined, but it is an indirect estimate of the cluster's distance. Also, Orion OB1b may have a depth of 40 pc along our line of sight. We use main-sequence fitting to nine main-sequence cluster members to estimate a best-fit distance of 420 +/- 30 pc, assuming a metallicity of -0.16 +/- 0.11 or 444 pc assuming solar metallicity. A distance as close as 350 pc is inconsistent with the observed brightnesses of the cluster members. At the best-fit distance, the age of the cluster is 2-3 Myr.

引用

页码：1616 / 1623

页数：8

共 61 条

[1]

Aitken R. G., 1932, New General Catalogue of Double Stars within 120 of the North Pole

[2] The distances to open clusters from main-sequence fitting. III. Improved accuracy with empirically calibrated isochrones [J].