2005ApJ...627L.149D


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.19CEST18:36:17

2005ApJ...627L.149D - Astrophys. J., 627, L149-L152 (2005/July-2)

X-ray diagnostics of grain depletion in matter accreting onto T Tauri stars.

DRAKE J.J., TESTA P. and HARTMANN L.

Abstract (from CDS):

Recent analysis of high-resolution Chandra X-ray spectra has shown that the Ne/O abundance ratio is remarkably constant in stellar coronae. Based on this result, we point out the utility of the Ne/O ratio as a discriminant for accretion-related X-rays from T Tauri stars and for probing the measure of grain depletion of the accreting material in the inner disk. We apply the Ne/O diagnostic to the classical T Tauri stars BP Tau and TW Hya–the two stars found to date whose X-ray emission appears to originate, at least in part, from accretion activity. We show that TW Hya appears to be accreting material that is significantly depleted in O relative to Ne. In contrast, BP Tau has an Ne/O abundance ratio consistent with that observed for post-T Tauri stars. We interpret this result in terms of the different ages and evolutionary states of the circumstellar disks of these stars. In the young BP Tau disk (age ∼0.6 Myr), dust is still present near the disk corotation radius and can be ionized and accreted, rereleasing elements depleted onto grains. In the more evolved TW Hya disk (age ∼10 Myr), evidence points to ongoing coagulation of grains into much larger bodies, and possibly planets, that can resist the drag of inward-migrating gas, and the accreting gas is consequently depleted of grain-forming elements.:

Abstract Copyright:

Journal keyword(s): Stars: Circumstellar Matter - Stars: Formation - Stars: Individual: Constellation Name: BP Tauri - Stars: Individual: Constellation Name: TW Hydrae - X-Rays: Stars

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 * eps Eri BY* 03 32 55.8449634 -09 27 29.731165 5.19 4.61 3.73 3.00 2.54 K2V 1713 1
2 V* BP Tau Or* 04 19 15.8342975037 +29 06 26.929456808   13.13 12.12 11.89   K5/7Ve 603 0
3 V* DF Tau Or* 04 27 02.7917481241 +25 42 22.456361256 11.97 12.25 11.42 10.31 9.14 M3Ve 462 1
4 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3542 0
5 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1765 0
6 V* TW Hya TT* 11 01 51.9054298616 -34 42 17.031550898   11.94 10.50 10.626 9.18 K6Ve 1553 1
7 HD 98800 RS* 11 22 05.28975 -24 46 39.7571   10.20 9.28 9.26 7.386 K5V(e) 333 0
8 CD-33 7795 TT* 11 31 55.2603055856 -34 36 27.214242128   12.97 11.524 11.150 9.150 M2Ve 176 0

    Equat.    Gal    SGal    Ecl

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2020.10.19-18:36:17

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