AN AGE ESTIMATE FOR THE BETA-PICTORIS ANALOG HR-4796A

Citation
Jr. Stauffer et al., AN AGE ESTIMATE FOR THE BETA-PICTORIS ANALOG HR-4796A, The Astrophysical journal, 454(2), 1995, pp. 910-916
Citations number
36
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
454
Issue
2
Year of publication
1995
Part
1
Pages
910 - 916
Database
ISI
SICI code
0004-637X(1995)454:2<910:AAEFTB>2.0.ZU;2-X
Abstract
We have obtained a high-resolution, moderate signal-to-noise spectrum for the M dwarf companion to HR 4796A, an A0 star with a beta Pictoris -type IR excess. The spectrum of the M star shows an extraordinarily s trong lithium 6708 Angstrom absorption line with an equivalent width o f similar to 550 m Angstrom. Age estimates derived from the lithium st rength and from pre-main-sequence isochrone fitting indicate an age of about 8 +/- 2 Myr for HR 4796B. Assuming this age is also applicable to HR 4796A, we conclude that HR 4796A is a relatively normal A star s een at an unusual time (i.e., when it is very young) rather than an A star of ''average'' age which has somehow managed to retain or acquire a dense, circumstellar disk, in rough agreement with conclusions reac hed previously by Jura et al.