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; Y. J. Kuan; I. M. Coulson

doi:10.1017/S1743921316002957

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, Y. J. Kuan, I. M. Coulson

Department of Earth Sciences (Include Institute of Marine Environmental Science and Technology)

Research output: Contribution to journal › Article › peer-review

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 language	English
Pages (from-to)	233-236
Number of pages	4
Journal	Proceedings of the International Astronomical Union
Volume	11
Issue number	A29A
DOIs	https://doi.org/10.1017/S1743921316002957
Publication status	Published - 2015

Keywords

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

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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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, Y. J., & 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

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, YJ & 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

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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.",

keywords = "Comets: individual (C/2012 K1 (PanSTARRS), molecular processes, submillimeter, techniques: interferometric",

author = "Cordiner, {M. A.} and Charnley, {S. B.} and Mumma, {M. J.} and D. Bockel{\'e}e-Morvan and N. Biver and G. Villanueva and L. Paganini and Milam, {S. N.} and Remijan, {A. J.} and Lis, {D. C.} and J. Crovisier and J. Boissier and Kuan, {Y. J.} and Coulson, {I. M.}",

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year = "2015",

doi = "10.1017/S1743921316002957",

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pages = "233--236",

journal = "Proceedings of the International Astronomical Union",

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T1 - Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

AU - Cordiner, M. A.

AU - Charnley, S. B.

AU - Mumma, M. J.

AU - Bockelée-Morvan, D.

AU - Biver, N.

AU - Villanueva, G.

AU - Paganini, L.

AU - Milam, S. N.

AU - Remijan, A. J.

AU - Lis, D. C.

AU - Crovisier, J.

AU - Boissier, J.

AU - Kuan, Y. J.

AU - Coulson, I. M.

PY - 2015

Y1 - 2015

N2 - 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.

AB - 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.

KW - Comets: individual (C/2012 K1 (PanSTARRS)

KW - molecular processes

KW - submillimeter

KW - techniques: interferometric

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JO - Proceedings of the International Astronomical Union

JF - Proceedings of the International Astronomical Union

IS - A29A

ER -

Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

Abstract

Keywords

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