Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

M. A. Cordiner, S. B. Charnley, M. J. Mumma, D. Bockelée-Morvan, N. Biver, G. Villanueva, L. Paganini, S. N. Milam, A. J. Remijan, D. C. Lis, J. Crovisier, J. Boissier, Yi-Jehng Kuan, I. M. Coulson

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (T rot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June, T rot fell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise in T rot at ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

Original languageEnglish
Pages (from-to)233-236
Number of pages4
JournalProceedings of the International Astronomical Union
Volume11
Issue numberA29A
DOIs
Publication statusPublished - 2015 Jan 1

Fingerprint

coma
excitation
solar heating
temperature
comets
temperature profile
temperature profiles
comet
line of sight
sky
irradiation
outflow
derivation
heating
cooling
kinetics
measuring
distribution
detection

Keywords

  • Comets: individual (C/2012 K1 (PanSTARRS)
  • molecular processes
  • submillimeter
  • techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics

Cite this

Cordiner, M. A., Charnley, S. B., Mumma, M. J., Bockelée-Morvan, D., Biver, N., Villanueva, G., ... Coulson, I. M. (2015). Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA. Proceedings of the International Astronomical Union, 11(A29A), 233-236. https://doi.org/10.1017/S1743921316002957

Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA. / Cordiner, M. A.; Charnley, S. B.; Mumma, M. J.; Bockelée-Morvan, D.; Biver, N.; Villanueva, G.; Paganini, L.; Milam, S. N.; Remijan, A. J.; Lis, D. C.; Crovisier, J.; Boissier, J.; Kuan, Yi-Jehng; Coulson, I. M.

In: Proceedings of the International Astronomical Union, Vol. 11, No. A29A, 01.01.2015, p. 233-236.

Research output: Contribution to journalArticle

Cordiner, MA, Charnley, SB, Mumma, MJ, Bockelée-Morvan, D, Biver, N, Villanueva, G, Paganini, L, Milam, SN, Remijan, AJ, Lis, DC, Crovisier, J, Boissier, J, Kuan, Y-J & Coulson, IM 2015, 'Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA', Proceedings of the International Astronomical Union, vol. 11, no. A29A, pp. 233-236. https://doi.org/10.1017/S1743921316002957
Cordiner MA, Charnley SB, Mumma MJ, Bockelée-Morvan D, Biver N, Villanueva G et al. Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA. Proceedings of the International Astronomical Union. 2015 Jan 1;11(A29A):233-236. https://doi.org/10.1017/S1743921316002957
Cordiner, M. A. ; Charnley, S. B. ; Mumma, M. J. ; Bockelée-Morvan, D. ; Biver, N. ; Villanueva, G. ; Paganini, L. ; Milam, S. N. ; Remijan, A. J. ; Lis, D. C. ; Crovisier, J. ; Boissier, J. ; Kuan, Yi-Jehng ; Coulson, I. M. / Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA. In: Proceedings of the International Astronomical Union. 2015 ; Vol. 11, No. A29A. pp. 233-236.
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