2012A&A...548A.124J


Query : 2012A&A...548A.124J

2012A&A...548A.124J - Astronomy and Astrophysics, volume 548A, 124-124 (2012/12-1)

Discovery of an outflow of the very low-mass star ISO 143.

JOERGENS V., KOPYTOVA T. and POHL A.

Abstract (from CDS):

We discover that the very young very low-mass star ISO143 (M5) is driving an outflow based on spectro-astrometry of forbidden [SII] emission lines at 6716Å and 6731Å observed in UVES/VLT spectra. This adds another object to the handful of brown dwarfs and very low-mass stars (M5-M8) for which an outflow has been confirmed and which show that the T Tauri phase continues at very low masses. We find the outflow of ISO143 to be intrinsically asymmetric and the accretion disk to not obscure the outflow, as only the red outflow component is visible in the [SII] lines. ISO143 is only the third T Tauri object showing a stronger red outflow component in spectro-astrometry, after RWAur (G5) and ISO217 (M6.25). We show here that, including ISO143, two out of seven outflows confirmed in the very low-mass regime (M5-M8) are intrinsically asymmetric. We measure a spatial extension of the outflow in [SII] of up to 200-300mas (about 30-50AU) and velocities of up to 50-70km/s. We furthermore detect line emission of ISO143 in CaII (8498Å), OI (8446Å), HeI (7065Å), and weakly in [FeII] (7155Å). Based on a line profile analysis and decomposition we demonstrate that (i) the CaII emission can be attributed to chromospheric activity, a variable wind, and the magnetospheric infall zone, (ii) the OI emission mainly to accretion-related processes but also a wind, and (iii) the HeI emission to chromospheric or coronal activity. We estimate a mass outflow rate of ISO143 of ∼10–10M/yr and a mass accretion rate in the range of ∼10–8 to ∼10–9M/yr. These values are consistent with those of other brown dwarfs and very low-mass stars. The derived {dot}(M)out/{dot}(M)acc ratio of 1-20% does not support previous findings of this number being very large (>40%) for very low-mass objects.

Abstract Copyright:

Journal keyword(s): stars: low-mass - stars: pre-main sequence - circumstellar matter - stars: individual: ISO 217 - stars: winds, outflows - techniques: high angular resolution

Simbad objects: 9

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Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 V* RW Aur TT* 05 07 49.5662483 +30 24 05.177426   10.86 9.60 9.95   K1/5e+K5e 761 0
2 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1085 1
3 ISO-ChaI 143 Y*? 11 08 22.3647237024 -77 30 27.783619596         15.51 M5e 42 0
4 ISO-ChaI 217 Y*O 11 09 52.1372780448 -76 39 12.876642648         16.63 ~ 44 0
5 TWA 27 LM* 12 07 33.4675524840 -39 32 54.016625184     19.95 17.99 15.88 M8IVe 329 0
6 V* V1192 Sco Or* 16 08 51.4348063536 -39 05 30.460358652     21.9 18.97 18.18 M5 66 0
7 [GY92] 3 Y*O 16 26 21.9078410496 -24 44 39.697627344       17.95 15.62 M6.5 52 0
8 [GY92] 204 TT* 16 27 06.5924837856 -24 41 48.871282992       17.57 15.43 M5 92 0
9 2MASS J19013357-3700304 Y*O 19 01 33.5761986624 -37 00 30.453110028           M6.5 44 0

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2022.11.28-12:07:09

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