Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422

Shigehisa Takakuwa, Nagayoshi Ohashi, Tyler L. Bourke, Naomi Hirano, T. P.Ho Paul, Jes K. Jørgensen, Y. I.Jehng Kuan, David J. Wilner, Sherry C.C. Yeh

Research output: Contribution to journalArticle

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Abstract

With the Submillimeter Array (SMA) we have made high angular resolution (∼1″ = 160 AU ) observations of the protobinary system IRAS 16293-2422 in the HCN (4-3), HC15N (4-3), and 354.5 GHz continuum emission. The HCN (4-3) line was also observed using the JCMT to supply missing short-spacing information. The submillimeter continuum emission is detected from the individual binary components of source A in the southeast and source B in the northwest, with a separation of ∼5″. The optically thin HC 15N (4-3) emission taken with the SMA has revealed a compact (∼500 AU) flattened structure (P.A. = -16°) at source A. This compact structure shows a velocity gradient along the projected minor axis, which can be interpreted as an infalling gas motion. Our HCN image including the short-spacing information shows an extended (∼3000 AU ) circumbinary envelope, as well as the compact structure at source A. A toy model consisting of a flattened structure with radial infall toward a 1 M central star reproduces the HCN/HC15N position-velocity diagram along the minor axis of the HC15N emission. In the extended envelope there is also a northeast (blue) to southwest (red) velocity gradient across the binary alignment, which is likely to reflect gas motion in the swept-up dense gas associated with the molecular outflow from source A. Only a weak and narrow (∼2 km s-1) compact HC15N emission is associated with source B, where no clear molecular outflow is identified, suggesting the different evolutionary starges between sources A and B. Our study demonstrates the importance of adding short-spacing data to interferometer data in order to probe the detailed structure and kinematics of low-mass protostellar envelopes.

Original languageEnglish
Pages (from-to)431-442
Number of pages12
JournalAstrophysical Journal
Volume662
Issue number1 I
DOIs
Publication statusPublished - 2007 Jun 10

Fingerprint

protostars
Infrared Astronomy Satellite
spacing
envelopes
outflow
gas
gases
interferometer
continuums
gradients
kinematics
diagram
probe
angular resolution
interferometers
diagrams
alignment
stars
probes
high resolution

Keywords

  • ISM: individual (IRAS 16293-2422)
  • ISM: molecules
  • Stars: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Takakuwa, S., Ohashi, N., Bourke, T. L., Hirano, N., Paul, T. P. H., Jørgensen, J. K., ... Yeh, S. C. C. (2007). Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422. Astrophysical Journal, 662(1 I), 431-442. https://doi.org/10.1086/513589

Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422. / Takakuwa, Shigehisa; Ohashi, Nagayoshi; Bourke, Tyler L.; Hirano, Naomi; Paul, T. P.Ho; Jørgensen, Jes K.; Kuan, Y. I.Jehng; Wilner, David J.; Yeh, Sherry C.C.

In: Astrophysical Journal, Vol. 662, No. 1 I, 10.06.2007, p. 431-442.

Research output: Contribution to journalArticle

Takakuwa, S, Ohashi, N, Bourke, TL, Hirano, N, Paul, TPH, Jørgensen, JK, Kuan, YIJ, Wilner, DJ & Yeh, SCC 2007, 'Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422', Astrophysical Journal, vol. 662, no. 1 I, pp. 431-442. https://doi.org/10.1086/513589
Takakuwa S, Ohashi N, Bourke TL, Hirano N, Paul TPH, Jørgensen JK et al. Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422. Astrophysical Journal. 2007 Jun 10;662(1 I):431-442. https://doi.org/10.1086/513589
Takakuwa, Shigehisa ; Ohashi, Nagayoshi ; Bourke, Tyler L. ; Hirano, Naomi ; Paul, T. P.Ho ; Jørgensen, Jes K. ; Kuan, Y. I.Jehng ; Wilner, David J. ; Yeh, Sherry C.C. / Arcsecond-resolution submillimeter HCN imaging of the binary protostar IRAS 16293-2422. In: Astrophysical Journal. 2007 ; Vol. 662, No. 1 I. pp. 431-442.
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