A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star

Details A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star

2005-01-14

arxiv.org/abs/astro-ph/0501307v1

Astrophys.J. 621 (2005) L65-L68

Astronomy and Astrophysics

Astrophysics

4 pages, including 2 figures. Accepted for publication in ApJ Lett

Scientific paper

10.1086/428752

We present a high dispersion optical spectrum of St 34 and identify the system as a spectroscopic binary with components of similar luminosity and temperature (both M3+/-0.5). Based on kinematics, signatures of accretion, and location on an H-R diagram, we conclude that St 34 is a classical T Tauri star belonging to the Taurus-Auriga T Association. Surprisingly, however, neither component of the binary shows LiI 6708 A, absorption, the most universally accepted criterion for establishing stellar youth. In this uniquely known instance, the accretion disk appears to have survived longer than the lithium depletion timescale. We speculate that the long-lived accretion disk is a consequence of the sub-AU separation companion tidally inhibiting, though not preventing, circumstellar accretion. Comparisons with pre-main sequence evolutionary models imply, for each component of St 34, a mass of 0.37+/-0.08 Msun and an isochronal age of 8+/-3 Myr, which is much younger than the predicted lithium depletion timescale of ~ 25 Myr. Although a distance 38% closer than that of Taurus-Auriga or a hotter temperature scale could reconcile this discrepancy at 21-25 Myr, similar discrepancies in other systems and the implications of an extremely old accreting Taurus-Auriga member suggest instead a possible problem with evolutionary models. Regardless, the older age implied by St 34's depleted lithium abundance is the first compelling evidence for a substantial age spread in this region. Additionally, since St 34's coeval co-members with early M spectral types would likewise fail the lithium test for youth, current membership lists may be incomplete.

Affiliated with

Also associated with

No associations

Rating

A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-26905