Hsieh, T-H, Murillo, NM, Belloche, A et al. (4 more authors) (2018) Probing Episodic Accretion in Very Low Luminosity Objects. Astrophysical Journal, 854 (1). 15. ISSN 0004-637X
Abstract
Episodic accretion has been proposed as a solution to the long-standing luminosity problem in star formation; however, the process remains poorly understood. We present observations of line emission from N2H+ and CO isotopologues using the Atacama Large Millimeter/submillimeter Array (ALMA) in the envelopes of eight very low luminosity objects (VeLLOs). In five of the sources the spatial distribution of emission from N2H+ and CO isotopologues shows a clear anticorrelation. It is proposed that this is tracing the CO snow line in the envelopes: N2H+ emission is depleted toward the center of these sources, in contrast to the CO isotopologue emission, which exhibits a peak. The positions of the CO snow lines traced by the N2H+ emission are located at much larger radii than those calculated using the current luminosities of the central sources. This implies that these five sources have experienced a recent accretion burst because the CO snow line would have been pushed outward during the burst because of the increased luminosity of the central star. The N2H+ and CO isotopologue emission from DCE161, one of the other three sources, is most likely tracing a transition disk at a later evolutionary stage. Excluding DCE161, five out of seven sources (i.e., ~70%) show signatures of a recent accretion burst. This fraction is larger than that of the Class 0/I sources studied by Jørgensen et al. and Frimann et al., suggesting that the interval between accretion episodes in VeLLOs is shorter than that in Class 0/I sources.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018. The American Astronomical Society. All rights reserved. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | astrochemistry; ISM: clouds; stars: formation; stars: low-mass; stars: protostars |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 27 Feb 2018 13:57 |
Last Modified: | 27 Feb 2018 13:57 |
Status: | Published |
Publisher: | American Astronomical Society |
Identification Number: | 10.3847/1538-4357/aaa7f6 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:127928 |