A 1.3 mm SMA survey of 29 variable young stellar objects

¹ European Southern Observatory (ESO), Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
e-mail: baobabyoo@gmail.com
² Department of Physics, State University of New York at Fredonia, 280 Central Ave, Fredonia, NY 14063, USA
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
⁴ Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
⁵ SKA Organisation, Jodrell Bank Observatory, Lower Withington, Macclesfield SK11 9DL, UK
⁶ Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, National Taiwan University, No 1, Sec., Roosevelt Road, 10617 Taipei, Taiwan
⁷ Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
⁸ Instituto de Radioastronomía y Astrofísica, UNAM, A.P. 3-72, Xangari, 58089 Morelia, Mexico
⁹ Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
¹⁰ Institut de Ciències de l’Espai (IEEC-CSIC), Can Magrans, S/N, 08193 Cerdanyola del Vallés, Catalonia, Spain
¹¹ Space Telescope Science Institute, Baltimore, MD 21218, USA
¹² Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Hungarian Academy of Science, Konkoly-Thege Miklósút 15-17, 1121 Budapest, Hungary
¹³ Max-Planck-Institut för Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹⁴ Institute of Fluid Mechanics and Heat Transfer, TU Wien, 1060 Vienna, Austria
¹⁵ Department of Astrophysics, University of Vienna, 1180 Vienna, Austria
¹⁶ Research Institute of Physics, Southern Federal University, 344090 Rostov-on-Don, Russia

Received: 14 September 2017
Accepted: 24 October 2017

Abstract

Context. Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess similar dust and gas reservoirs to each other, and whether or not their dust and gas reservoirs are similar as quiescent YSOs, are issues yet to be clarified. Aims. The aim of this work is to characterize the millimeter thermal dust emission properties of a statistically significant sample of long and short duration accretion outburst YSOs (i.e., FUors and EXors) and the spectroscopically identified candidates of accretion outbursting YSOs (i.e., FUor-like objects).

Methods. We have carried out extensive Submillimeter Array (SMA) observations mostly at ~225 GHz (1.33 mm) and ~272 GHz (1.10 mm), from 2008 to 2017. We covered accretion outburst YSOs located at <1 kpc distances from the solar system.

Results. We analyze all the existing SMA data of such objects, both published and unpublished, in a coherent way to present a millimeter interferometric database of 29 objects. We obtained 21 detections at >3σ significance. Detected sources except for the two cases of V883 Ori and NGC 2071 MM3 were observed with ~1″ angular resolution. Overall our observed targets show a systematically higher millimeter luminosity distribution than those of the M_* > 0.3 M_⊙ Class II YSOs in the nearby (≲400 pc) low-mass star-forming molecular clouds (e.g., Taurus, Lupus, Upp Scorpio, and Chameleon I). In addition, at 1 mm our observed confirmed binaries or triple-system sources are systematically fainter than the rest of the sources even though their 1 mm fluxes are broadly distributed. We may have detected ~30−60% millimeter flux variability from V2494 Cyg and V2495 Cyg, from the observations separated by approximately one year.