A centrally concentrated sub-solar-mass starless core in the Taurus L1495 filamentary complex

Kazuki Tokuda, Kengo Tachihara, Kazuya Saigo, Phillipe André, Yosuke Miyamoto, Sarolta Zahorecz, Shu Ichiro Inutsuka, Tomoaki Matsumoto, Tatsuyuki Takashima, Masahiro N. Machida, Kengo Tomida, Kotomi Taniguchi, Yasuo Fukui, Akiko Kawamura, Ken'ichi Tatematsu, Ryo Kandori, Toshikazu Onishi

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The formation scenario of brown dwarfs is still unclear because observational studies to investigate its initial condition are quite limited. Our systematic survey of nearby low-mass star-forming regions using the Atacama Compact Array (aka the Morita array) and the IRAM 30-m telescope in 1.2 mm continuum has identified a centrally concentrated starless condensation with a central H2 volume density of ∼106 cm-3, MC5-N, connected to a narrow (width ∼0.03 pc) filamentary cloud in the Taurus L1495 region. The mass of the core is ∼ 0.2-0.4, Mo , which is an order of magnitude smaller than typical low-mass pre-stellar cores. Taking into account a typical core to star formation efficiency for pre-stellar cores (∼20%-40%) in nearby molecular clouds, brown dwarf(s) or very low-mass star(s) may be going to be formed in this core. We have found possible substructures at the high-density portion of the core, although much higher angular resolution observation is needed to clearly confirm them. The subsequent N2H+ and N2D+ observations using the Nobeyama 45-m telescope have confirmed the high-deuterium fractionation (∼30%). These dynamically and chemically evolved features indicate that this core is on the verge of proto-brown dwarf or very low-mass star formation and is an ideal source to investigate the initial conditions of such low-mass objects via gravitational collapse and/or fragmentation of the filamentary cloud complex.

Original languageEnglish
Article number73
JournalPublications of the Astronomical Society of Japan
Volume71
Issue number4
DOIs
Publication statusPublished - 2019 Aug 1
Externally publishedYes

Keywords

  • ISM: clouds
  • ISM: individual objects (L1495, MC5-N)
  • stars: formation
  • stars: low-mass

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Tokuda, K., Tachihara, K., Saigo, K., André, P., Miyamoto, Y., Zahorecz, S., Inutsuka, S. I., Matsumoto, T., Takashima, T., Machida, M. N., Tomida, K., Taniguchi, K., Fukui, Y., Kawamura, A., Tatematsu, K., Kandori, R., & Onishi, T. (2019). A centrally concentrated sub-solar-mass starless core in the Taurus L1495 filamentary complex. Publications of the Astronomical Society of Japan, 71(4), [73]. https://doi.org/10.1093/pasj/psz051