Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde)

Masatoshi Ohishi, Shin Ichi Ishikawa, Takayoshi Amano, Hidehiko Oka, William M. Irvine, James E. Dickens, Lucy M Ziurys, A. J. Apponi

Research output: Contribution to journalArticle

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Abstract

A new interstellar molecular ion, H2COH+ (protonated formaldehyde), has been detected toward Sgr B2, Orion KL, W51, and possibly in NGC 7538 and DR21(OH). Six transitions were detected in Sgr B2(M). The 11,0-10,1 transition was detected in all sources listed above. Searches were also made toward the cold, dark clouds TMC-1 and L134N, Orion (3N, 1E), and a red giant, IRC +10216, without success. The excitation temperatures of H2COH+ are calculated to be 60-110 K, and the column densities are on the order of 1012-1014 cm-2 in Sgr B2, Orion KL, and W51. The fractional abundance of H2COH+ is on the order of 10-11 to 10-9, and the ratio of H2COH+ to H2CO is in the range 0.001-0.5 in these objects. The values in Orion KL seem to be consistent with the "early time" values of recent model calculations by Lee, Bettens, & Herbst, but they appear to be higher than the model values in Sgr B2 and W51 even if we take the large uncertainties of column densities of H2CO into account. We suggest production routes starting from CH3 OH may play an important role in the formation of H2COH+.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume471
Issue number1 PART II
StatePublished - 1996
Externally publishedYes

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formaldehyde
molecular ions
ion
temperature
routes
detection
excitation
cold
calculation

Keywords

  • ISM: abundances
  • ISM: molecules

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Ohishi, M., Ishikawa, S. I., Amano, T., Oka, H., Irvine, W. M., Dickens, J. E., ... Apponi, A. J. (1996). Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde). Astrophysical Journal, 471(1 PART II).

Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde). / Ohishi, Masatoshi; Ishikawa, Shin Ichi; Amano, Takayoshi; Oka, Hidehiko; Irvine, William M.; Dickens, James E.; Ziurys, Lucy M; Apponi, A. J.

In: Astrophysical Journal, Vol. 471, No. 1 PART II, 1996.

Research output: Contribution to journalArticle

Ohishi, M, Ishikawa, SI, Amano, T, Oka, H, Irvine, WM, Dickens, JE, Ziurys, LM & Apponi, AJ 1996, 'Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde)', Astrophysical Journal, vol. 471, no. 1 PART II.
Ohishi M, Ishikawa SI, Amano T, Oka H, Irvine WM, Dickens JE et al. Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde). Astrophysical Journal. 1996;471(1 PART II).
Ohishi, Masatoshi ; Ishikawa, Shin Ichi ; Amano, Takayoshi ; Oka, Hidehiko ; Irvine, William M. ; Dickens, James E. ; Ziurys, Lucy M ; Apponi, A. J. / Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde). In: Astrophysical Journal. 1996 ; Vol. 471, No. 1 PART II.
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AU - Ohishi, Masatoshi

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AU - Amano, Takayoshi

AU - Oka, Hidehiko

AU - Irvine, William M.

AU - Dickens, James E.

AU - Ziurys, Lucy M

AU - Apponi, A. J.

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N2 - A new interstellar molecular ion, H2COH+ (protonated formaldehyde), has been detected toward Sgr B2, Orion KL, W51, and possibly in NGC 7538 and DR21(OH). Six transitions were detected in Sgr B2(M). The 11,0-10,1 transition was detected in all sources listed above. Searches were also made toward the cold, dark clouds TMC-1 and L134N, Orion (3N, 1E), and a red giant, IRC +10216, without success. The excitation temperatures of H2COH+ are calculated to be 60-110 K, and the column densities are on the order of 1012-1014 cm-2 in Sgr B2, Orion KL, and W51. The fractional abundance of H2COH+ is on the order of 10-11 to 10-9, and the ratio of H2COH+ to H2CO is in the range 0.001-0.5 in these objects. The values in Orion KL seem to be consistent with the "early time" values of recent model calculations by Lee, Bettens, & Herbst, but they appear to be higher than the model values in Sgr B2 and W51 even if we take the large uncertainties of column densities of H2CO into account. We suggest production routes starting from CH3 OH may play an important role in the formation of H2COH+.

AB - A new interstellar molecular ion, H2COH+ (protonated formaldehyde), has been detected toward Sgr B2, Orion KL, W51, and possibly in NGC 7538 and DR21(OH). Six transitions were detected in Sgr B2(M). The 11,0-10,1 transition was detected in all sources listed above. Searches were also made toward the cold, dark clouds TMC-1 and L134N, Orion (3N, 1E), and a red giant, IRC +10216, without success. The excitation temperatures of H2COH+ are calculated to be 60-110 K, and the column densities are on the order of 1012-1014 cm-2 in Sgr B2, Orion KL, and W51. The fractional abundance of H2COH+ is on the order of 10-11 to 10-9, and the ratio of H2COH+ to H2CO is in the range 0.001-0.5 in these objects. The values in Orion KL seem to be consistent with the "early time" values of recent model calculations by Lee, Bettens, & Herbst, but they appear to be higher than the model values in Sgr B2 and W51 even if we take the large uncertainties of column densities of H2CO into account. We suggest production routes starting from CH3 OH may play an important role in the formation of H2COH+.

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