J/A+A/633/A126 Cha-MMS1 CO 3-2 and 13CO 3-2 datacubes (Busch+, 2020)
The dynamically young outflow of the Class 0 protostar Cha-MMS1.
Busch L.A., Belloche A., Cabrit S., Hennebelle P., Commercon B.
<Astron. Astrophys. 633, A126 (2020)>
=2020A&A...633A.126B 2020A&A...633A.126B (SIMBAD/NED BibCode)
ADC_Keywords: Protostars ; YSOs ; Carbon monoxide
Keywords: stars: formation - stars: protostars - stars: jets -
ISM: jets and outflows
Abstract:
On the basis of its low luminosity, its chemical composition, and the
absence of a large-scale outflow, the dense core Cha-MMS1 located in
the Chamaeleon I molecular cloud was proposed as a first hydrostatic
core (FHSC) candidate a decade ago.
Our goal is to test this hypothesis by searching for a slow, compact
outflow driven by Cha-MMS1 that would match the predictions of MHD
simulations for this short phase of star formation. We use the Atacama
Large Millimeter/submillimeter Array (ALMA) to map Cha-MMS1 at high
angular resolution in CO 3-2 and 13CO 3-2 as well as in continuum
emission.
We report the detection of a bipolar outflow emanating from the
central core, along a (projected) direction roughly parallel to the
filament in which Cha-MMS1 is embedded and perpendicular to the
large-scale magnetic field. The morphology of the outflow indicates
that its axis lies close to the plane of the sky. We measure
velocities corrected for inclination of more than 90km/s which is
clearly incompatible with the expected properties of a FHSC outflow.
Several properties of the outflow are determined and compared to
previous studies of Class 0 and Class I protostars. The outflow of
Cha-MMS1 has a much smaller momentum force than the outflows of other
Class0 protostars. In addition, we find a dynamical age of 200-3000yr
indicating that Cha-MMS1 might be one of the youngest ever observed
Class 0 protostars. While the existence of the outflow suggests the
presence of a disk, no disk is detected in continuum emission and we
derive an upper limit of 55au to its radius.
We conclude that Cha-MMS1 has already gone through the FHSC phase and
is a young Class 0 protostar, but it has not brought its outflow to
full power yet.
Description:
We used ALMA to observe Cha-MMS1 in CO 3-2 and 13CO 3-2 emission.
The field was centered at J2000,RA=11:06:33.13, DE=-77:23:35.1. The
observations were conducted in several sessions during Cycle 3 in two
different configurations.
Objects:
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RA (2000) DE Designation(s)
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11 06 33.38 -77 23 34.6 Cha-MMS1 = [RNC96] Cha-MMS 1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 130 2 List of fits files
fits/* . 2 Individual fits files
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See also:
J/A+A/564/A99 : Chamaeleon-MMS1 NH3 (1,1) and (2,2) maps (Vaisala+, 2014)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right Ascension of center (J2000)
4- 5 I2 min RAm Right Ascension of center (J2000)
7- 11 F5.2 s RAs Right Ascension of center (J2000)
12 A1 --- DE- Declination sign of center (J2000)
13- 14 I2 deg DEd Declination of center (J2000)
16- 17 I2 arcmin DEm Declination of center (J2000)
19- 22 F4.1 arcsec DEs Declination of center (J2000)
24- 26 I3 --- Nx Number of pixels along X-axis
28- 30 I3 --- Ny Number of pixels along Y-axis
32- 35 I4 --- Nz Number of channels along the spectral axis
37- 42 F6.2 GHz bFreq Minimum frequency of spectral axis
44- 49 F6.2 GHz BFreq Maximum frequency of spectral axis
51- 55 F5.1 kHz dFreq Frequency resolution
57- 63 I7 Kibyte size Size of FITS file
65- 88 A24 --- FileName Name of FITS file, in subdirectory fits
90-130 A41 --- Title Title of the file
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Acknowledgements:
Laura Ann Busch, labusch(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 30-Dec-2019