2001A&A...380..264F


Query : 2001A&A...380..264F

2001A&A...380..264F - Astronomy and Astrophysics, volume 380, 264-276 (2001/12-2)

Intense accretion and mass loss of a very low mass young stellar object.

FERNANDEZ M. and COMERON F.

Abstract (from CDS):

We present visible and near-infrared photometry and spectroscopy of LS-RCrA 1, a faint, very late-type object (M 6.5-M 7) seen in the direction of the R Coronae Australis star forming complex. While its emission spectrum shows prominent features of accretion and mass loss typical of young stellar objects, its underlying continuum and photometric properties are puzzling when trying to derive a mass and age based on pre-main sequence evolutionary tracks: the object appears to be far too faint for a young member of the R Coronae Australis complex of its spectral type. We speculate that this may be due to either its evolution along pre-main sequence tracks being substantially altered by the intense accretion, or to a combination of partial blocking and scattering of the light of the object by a nearly edge-on circumstellar disk. The rich emission line spectrum superimposed on the stellar continuum is well explained by an intense accretion process: the Hα, CaII infrared triplet, and HeI 6678 lines show equivalent widths typical of very active classical T Tauri stars. The near-infrared observations show anomalously weak spectral features and no significant excess emission in the K band, which we tentatively interpret as indicating line filling due to emission in a magnetic accretion funnel flow. At the same time, numerous, strong forbidden optical lines ([OI], [NII] and [SII]) and H2 emission at 2.12 µm suggest that the object is simultaneously undergoing mass loss, providing another example that shows that mass loss and accretion are closely related processes. Such an intense accretion and mass loss activity is observed for the first time in a young stellar object in the transition region between low mass stars and brown dwarfs, and provides a valuable observational test on the effects of accretion on the evolution of objects with such low masses.

Abstract Copyright:

Journal keyword(s): stars: circumstellar matter, low-mass and brown dwarfs, mass-loss, pre-main sequence, winds, outflows - Galaxy: open clusters and associations: individual: R Coronae Australis

Nomenclature: Tables 1, 2: LS-RCrA N (Nos 1-2).

Simbad objects: 27

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Number of rows : 27
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 IC 348 OpC 03 44 31.7 +32 09 32           ~ 1393 1
2 [SS94] V410 X-ray 3 TT* 04 18 07.9729489560 +28 26 03.667161660     18.319     M6 74 0
3 V* V1213 Tau Or* 04 31 37.5055489536 +18 12 24.383952396           K7 568 0
4 V* HL Tau Or* 04 31 38.5107609312 +18 13 57.859747968   15.89 14.49 14.39   K5 1424 0
5 IRAS 04287+1807 mul 04 31 38.8 +18 13 57           ~ 796 0
6 V* HV Tau C TT* 04 38 35.5125950280 +26 10 41.316576204         14.90 K6 98 0
7 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4416 0
8 V* RW Aur TT* 05 07 49.5662483 +30 24 05.177426   10.86 9.60 9.95   K1/5e+K5e 781 0
9 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 579 0
10 HH 34 HH 05 35 31.30 -06 28 43.0     16     ~ 488 2
11 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1154 1
12 WRAY 16-203 Or* 16 08 29.7275063376 -39 03 11.024360496   16.26 15.91 15.38 15.69 K0: 171 1
13 CD-38 10980 WD* 16 23 33.8380498896 -39 13 46.161043572 9.916 10.885 11.029 10.936 10.841 DA2 483 0
14 [RR90] Oph 2320.8-1721 Y*O 16 26 22.26912 -24 24 07.0632           M8 70 0
15 [RR90] Oph 2349.8-2601 Y*O 16 26 51.2924609616 -24 32 42.001375272           M8.5 53 0
16 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3631 1
17 NGC 6405 OpC 17 40 16.6 -32 14 31           ~ 201 0
18 HH 80A HH 18 19 06.09 -20 51 50.4           ~ 10 0
19 2MASS J19013357-3700304 Y*O 19 01 33.5761986624 -37 00 30.453110028           M6.5 45 0
20 V* V709 CrA Or* 19 01 34.8589591776 -37 00 56.579123412   12.70 11.03     K1IV 63 0
21 HH 101 HH 19 01 42 -37 00.7           ~ 44 0
22 HH 100 HH 19 01 49.1 -36 58 16           ~ 81 0
23 UCAC4 265-183516 Y*O 19 01 49.3660476264 -37 00 28.636309008   18.4   16.6   M4.0 13 0
24 V* R CrA Ae* 19 01 53.6764322232 -36 57 08.299341828 12.781 12.651 11.917 11.242 10.412 B5IIIpe 478 1
25 V* T CrA Ae* 19 01 58.7902764120 -36 57 50.339720880     11.67     F0 167 0
26 NAME CrA Complex reg 19 15 00.0 -37 30 00           ~ 109 1
27 HD 188112 HS* 19 54 31.4191828536 -28 20 20.679710640   10.01 10.22     sdB 96 0

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