Membership of the {epsilon} Cha association Virtual Observatory Resource

Authors
  1. Murphy S.J.
  2. Lawson W.A.
  3. Bessell M.S.
  4. Published by
    CDS
Abstract

We present a comprehensive investigation of the {epsilon} Chamaeleontis association, one of several young moving groups spread across the southern sky. We re-assess the putative membership of {epsilon} Cha using the best available proper motion and spectroscopic measurements, including new ANU 2.3-m/Wide Field Spectrograph observations. After applying a kinematic analysis, our final membership comprises 35-41 stars from B9 to mid-M spectral types. Theoretical evolutionary models suggest {epsilon} Cha is 3-5Myr old, distinguishing it as the youngest moving group in the solar neighbourhood. 15 members show 3-22um spectral energy distributions attributable to circumstellar discs, including 11 stars which appear to be actively accreting. {epsilon} Cha's disc and accretion fractions are both consistent with a typical 3-5Myr old population. Multi-epoch spectroscopy reveals three M-type members with broad and highly variable Ha emission as well as several new spectroscopic binaries. We reject 11 stars proposed as members in the literature and suggest they may belong to the background Cha I and II clouds or other nearby young groups. Our analysis underscores the importance of a holistic and conservative approach to assigning young stars to kinematic groups, many of which have only subtly different properties and ill-defined memberships. We conclude with a brief discussion of {epsilon} Cha's connection to the young open cluster eta Cha and the Scorpius- Centaurus OB association. Contrary to earlier studies which assumed eta and {epsilon} Cha are coeval and were born in the same location, we find the groups were separated by ~30pc when eta Cha formed 4-8Myr ago in the outskirts of Sco-Cen, 1-3Myr before the majority of {epsilon} Cha members.

Keywords
  1. Stellar associations
  2. Pre-main sequence stars
  3. Radial velocity
  4. Stellar ages
  5. Line intensities
Bibliographic source Bibcode
2013MNRAS.435.1325M
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/435/1325
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/435/1325

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/435/1325
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/435/1325
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/435/1325
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/435/1325/stars?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/435/1325/stars?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/435/1325/stars?

History

2013-09-26T08:36:21Z
Resource record created
2013-09-26T08:36:21Z
Created
2017-09-29T09:03:56Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr