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J/A+A/615/A9       Distribution of Serpens South protostars    (Plunkett+, 2018)

Distribution of Serpens South protostars revealed with ALMA. Plunkett A.L., Fernandez-Lopez M., Arce H., Busquet G., Mardones D., Dunham M.M <Astron. Astrophys. 615, A9 (2018)> =2018A&A...615A...9P (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Protostars ; Interferometry Keywords: stars: formation - stars: protostars - submillimeter: stars - techniques: interferometric - methods: observational Abstract: Clusters are common sites of star formation, whose members display varying degrees of mass segregation. The cause may be primordial or dynamical, or a combination both. If mass segregation were to be observed in a very young protostellar cluster, then the primordial case can be assumed more likely for that region. We investigated the masses and spatial distributions of pre-stellar and protostellar candidates in the young, low-mass star forming region Serpens South, where active star formation is known to occur along a predominant filamentary structure. Previous observations used to study these distributions have been limited by two important observational factors: (1) sensitivity limits that leave the lowest-mass sources undetected, or (2) resolution limits that cannot distinguish binaries and/or cluster members in close proximity. Recent millimeter-wavelength interferometry observations can now uncover faint and/or compact sources in order to study a more complete population of protostars, especially in nearby (D<500pc) clusters. Here we present ALMA observations of 1mm (Band 6) continuum in a 3x2-arcminutes region at the center of Serpens South. Our angular resolution of 1-arcsec is equivalent to 400 au, corresponding to scales of envelopes and/or disks of protostellar sources. We detect 52 sources with 1mm continuum, and we measure masses of 0.002-0.9 solar masses corresponding to gas and dust in the disk and/or envelope of the protostellar system. For the deeply embedded (youngest) sources with no IR counterparts, we find evidence of mass segregation and clustering according to: the Minimum Spanning Tree method, distribution of projected separations between unique sources, and concentration of higher-mass sources near to the dense gas at the cluster center. The mass segregation of the mm sources is likely primordial rather than dynamical given the young age of this cluster, compared with segregation time. This is the first case to show this for mm sources in a low-mass protostellar cluster environment. Description: Here we provide the ALMA Band 6 continuum observations of Serpens South, which are part of the project 2012.1.00769.S, PI: A. Plunkett. Data obtained with the 12m array and 7m array have been combined in the uv plane to create these maps. We include two maps, one without the primary beam (PB) correction and one with the PB correction. Objects: ------------------------------------------------------------------ RA (2000) DE Designation(s) ------------------------------------------------------------------ 18 30 03.00 -02 01 58.2 Serpens South = Serpens South Cluster ------------------------------------------------------------------ File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 132 2 List of fits images fits/* 0 2 Individual fits images
See also: J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 23 I4 --- Nx Number of pixels along X-axis 25- 28 I4 --- Ny Number of pixels along Y-axis 30- 51 A22 --- Obs.Date Observation date (2014-03-22T08:59:09.84) 53- 58 F6.2 GHz Freq Observed frequency 60- 63 I4 Kibyte size Size of FITS file 65- 76 A12 --- FileName Name of FITS file, in subdirectory fits 78-132 A55 --- Title Title of the FITS file
Acknowledgements: Adele L. Plunkett, aplunket[at]eso.org
(End) Adele L. Plunkett [ESO], Patricia Vannier [CDS] 07-Apr-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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