Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/7762
Title: Gas infalling motions in the envelopes of very low luminosity objects
Authors: Kim, Mi-Ryang
Lee, Chang Won
Maheswar, G
Myers, Philip C
Kim, Gwanjeong
Keywords: Protostars
Brown dwarfs
Collapsing clouds
Issue Date: 1-Apr-2021
Publisher: IOP Publishing
Citation: The Astrophysical Journal, Vol. 910, No. 2, 112
Abstract: We present the results of a single-dish survey toward 95 very low luminosity objects (VeLLOs) in optically thick (HCN 1−0) and thin (N2H+ 1−0) lines performed for the purpose of understanding the physical processes of inward motions in the envelopes of the VeLLOs and characterizing their true nature. The normalized velocity differences (dVHCN) between the peak velocities of the two lines were derived for 41 VeLLOs detected in both lines. The δV distribution of these VeLLOs is found to be significantly skewed to the blue, indicating the dominance of infalling motions in their envelopes. The infall speeds were derived for 15 infall candidates by using the HILL5 radiative transfer model. The speeds were in the range of 0.03−0.3 km s−1 , with a median value of 0.16 km s−1 , consistent with the gravitational freefall speeds from pressure-free envelopes. The mass infall rates calculated from the infall speeds are mostly of the order of 10−6 Me yr−1 , with a median value of (3.4 ± 1.5) × 10−6 Me yr−1 . These are found to be also consistent with the values predicted with the inside-out collapse model and show a fairly good correlation with the internal luminosities of the VeLLOs. This again indicates that the infall motions observed toward the VeLLOs are likely to be due to the gravitational infall motions in their envelopes. Our study suggests that most of the VeLLOs are potentially faint protostars, while two of the VeLLOs could possibly be proto−brown dwarf candidates.
Description: Restricted Access
URI: http://hdl.handle.net/2248/7762
ISSN: 1538-4357
Appears in Collections:IIAP Publications

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