JCMT Spectral and Continuum Imaging of Comet 252P/LINEAR

Iain M. Coulson, Martin A. Cordiner, Yi-Jehng Kuan, Wei-Ling Tseng, Yo Ling Chuang, Zhong Yi Lin, Stefanie N. Milam, Steven B. Charnley, Wing Huen Ip

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Comet 252P/LINEAR passed the Earth at a distance of 0.035 au on 2016 March 21, presenting a rare opportunity to study a comet at high spatial resolution. Even with a single dish facility such as JCMT, the chemical structure of the coma could be observed on scales of 500-1000 km, which are smaller than the scale lengths of known distributed cometary molecules. Our week-long observing campaign at JCMT started on March 27 (UT), 12 days after perihelion, and ended on April 3, during which time the comet's distance from Earth increased from 0.045 to 0.078 au. Our observations of the J = 4 - 3 transition of HCN showed generally uniform levels of activity. Expansion velocities were ∼0.6 km s-1 (±10%), and the derived mean HCN production rate during the week was 6.4 ×1024 mol s-1. Comparison with independent estimates of the water production rate during the same period yields a mixing ratio of 0.12% with respect to water. Methanol emissions appear to arise from an extended source - probably in the form of an ice halo - suggesting that all the gases from 252P may originate in large part from the sublimation of icy grains in the coma. Adopting a mean dust particle size of 1 mm, the mass of dust in the coma at the same time is estimated at 4 ×107 kg, implying a total dust production rate of 4 kg s-1. The dust-to-gas mass ratio of ∼0.025 is one of the lowest values ever observed for a comet.

Original languageEnglish
Article number169
JournalAstronomical Journal
Volume153
Issue number4
DOIs
Publication statusPublished - 2017 Apr 1

Fingerprint

comets
comet
coma
dust
continuums
parabolic reflectors
sublimation
mixing ratios
gases
gas
mixing ratio
mass ratios
water
methanol
halos
ice
spatial resolution
methyl alcohol
particle size
expansion

Keywords

  • comets: individual (252P/LINEAR)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Coulson, I. M., Cordiner, M. A., Kuan, Y-J., Tseng, W-L., Chuang, Y. L., Lin, Z. Y., ... Ip, W. H. (2017). JCMT Spectral and Continuum Imaging of Comet 252P/LINEAR. Astronomical Journal, 153(4), [169]. https://doi.org/10.3847/1538-3881/aa6440

JCMT Spectral and Continuum Imaging of Comet 252P/LINEAR. / Coulson, Iain M.; Cordiner, Martin A.; Kuan, Yi-Jehng; Tseng, Wei-Ling; Chuang, Yo Ling; Lin, Zhong Yi; Milam, Stefanie N.; Charnley, Steven B.; Ip, Wing Huen.

In: Astronomical Journal, Vol. 153, No. 4, 169, 01.04.2017.

Research output: Contribution to journalArticle

Coulson, IM, Cordiner, MA, Kuan, Y-J, Tseng, W-L, Chuang, YL, Lin, ZY, Milam, SN, Charnley, SB & Ip, WH 2017, 'JCMT Spectral and Continuum Imaging of Comet 252P/LINEAR', Astronomical Journal, vol. 153, no. 4, 169. https://doi.org/10.3847/1538-3881/aa6440
Coulson, Iain M. ; Cordiner, Martin A. ; Kuan, Yi-Jehng ; Tseng, Wei-Ling ; Chuang, Yo Ling ; Lin, Zhong Yi ; Milam, Stefanie N. ; Charnley, Steven B. ; Ip, Wing Huen. / JCMT Spectral and Continuum Imaging of Comet 252P/LINEAR. In: Astronomical Journal. 2017 ; Vol. 153, No. 4.
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