J/A+A/552/L2 SINFONI K-band observations of IRS54(YLW52) (Garcia Lopez+, 2013)
Spatially resolved H2 emission form a very low-mass star.
Garcia Lopez R., Caratti o Garatti A., Weigelt G., Nisini B., Antoniucci S.
<Astron. Astrophys. 552, L2 (2013)>
=2013A&A...552L...2G 2013A&A...552L...2G
ADC_Keywords: Infrared sources; Interstellar medium; YSOs; Spectra, infrared
Keywords: stars: formation - circumstellar matter - stars: winds, outflows -
ISM: jets and outflows - infrared: ISM
Abstract:
Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs
have been studied very little. So far, only a few CO outflows have
been observed, allowing us to map the immediate circumstellar
environment. We present the first spatially resolved H2 emission
around IRS54 (YLW52), a ∼0.1-0.2M☉ Class I source.
By means of VLT SINFONI K-band observations, we probed the H2 emission
down to the first ∼50AU from the source.
The molecular emission shows a complex structure delineating a large
outflow cavity and an asymmetric molecular jet. Thanks to the
detection of several H2transitions, we are able to estimate average
values along the jet-like structure (from source position to knot D)
of Av∼28mag, T∼2000-3000K, and H2column density
N(H_2)∼1.7x1017cm-2. This allows us to estimate a mass loss rate of
∼2x10^-10M☉/yr for the warm H2component .
In addition, from the total flux of the Br gamma line, we infer an
accretion luminosity and mass accretion rate of 0.64L☉ and
∼3x10^-7M☉/yr, respectively. The outflow structure is similar to
those found in low-mass Class I and CTTS. However, the Lacc/Lbol ratio
is very high (∼80%), and the mass accretion rate is about one order of
magnitude higher when compared to objects of roughly the same mass,
pointing to the young nature of the investigated source.
Description:
SINFONI K-band integral field spectroscopic datacube of the YSO IRS54
(YLW52) at medium resolution (R∼4000).
The main data reduction process was done using the SINFONI
data-reduction pipeline, i.e., dark and bad pixel masks, flat-field
corrections, optical distortion correction, and wavelength calibration
using arc lamps.
A systematic wavelength shift of ∼2.2 Angstroms was found and should
be taken into account.
The STARLINK software was used to correct the spectrum from
atmospheric absorption and to flux-calibrate the data. Flux units are
erg/s/cm^2; Wavelength units are microns.
Objects:
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RA (2000) DE Designation(s)
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16 27 51.81 -24 31 45.5 YLW52 = WLY 2-54
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 74 1 List of fits file
fits/* . 1 K-band IFS datacube
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 F4.2 arcsec/pix scale Scale of the image
25- 26 I2 pix Nx Number of pixels along X-axis
27 A1 --- --- [x]
28- 29 I2 pix Ny Number of pixels along Y-axis
30 A1 --- --- [x]
31- 34 I4 pix Nz Number of slice
36- 42 F7.5 um lam0 Lower value of wavelength interval
43 A1 --- --- [/]
44- 50 F7.5 um lam1 Upper value of wavelength interval
52- 59 F8.6 um dlam resolution in Wave
61- 74 A14 --- FileName Name of FITS file in subdirectory fits
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Acknowledgements:
Rebeca Garcia Lopez, rgarcia(at)mpifr-bonn.mpg.de
(End) Rebeca Garcia Lopez [MPIfR, Germany], Patricia Vannier [CDS] 26-Feb-2013