A SEARCH FOR INTERSTELLAR CARBON-CHAIN ALCOHOL HC{sub 4}OH IN STAR-FORMING REGION L1527 AND DARK CLOUD TMC-1

Journal Article · Tue Jan 10 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/744/2/163· OSTI ID:22004217

Araki, Mitsunori; Yamabe, Hiromichi; Koshikawa, Naohiro; Tsukiyama, Koichi ^[1]; Takano, Shuro ^[2]; Nakane, Aya; Okabayashi, Toshiaki ^[3]; Kunimatsu, Arisa; Kuze, Nobuhiko ^[4]

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1. Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku 162-8601, Tokyo (Japan)
2. Nobeyama Radio Observatory, 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)
3. Department of Chemistry, Faculty of Science, Shizuoka University, 836 Oya, Suruga-ku, Shizuoka 422-8529 (Japan)
4. Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku 102-8554, Tokyo (Japan)

We report a sensitive search for the rotational transitions of the carbon-chain alcohol HC{sub 4}OH in the frequency range 21.2-46.7 GHz in the star-forming region L1527 and the dark cloud TMC-1. The motivation was laboratory detection of HC{sub 4}OH by microwave spectroscopy. Despite achieving rms noise levels of several millikelvin in the antenna temperature using the 45 m telescope at Nobeyama Radio Observatory, the detection was not successful, leading to 3{sigma} upper limits corresponding to the column densities of 2.0 Multiplication-Sign 10{sup 12} and 5.6 Multiplication-Sign 10{sup 12} cm{sup -2} in L1527 and TMC-1, respectively. These upper limits indicate that [HC{sub 4}OH]/[HC{sub 5}N] ratios are less than 0.3 and 0.1 in L1527 and TMC-1, respectively, where HC{sub 5}N is an HC{sub 4}-chain cyanide and HC{sub 4}OH is a hydroxide. These ratios suggest that the cyano carbon-chain molecule dominates the hydroxyl carbon-chain molecule in L1527 and TMC-1. This is contrary to the case of saturated compounds in hot cores, e.g., CH{sub 3}OH and CH{sub 3}CN, and can be a chemical feature of carbon-chain molecules in L1527 and TMC-1. In addition, the column densities of the 'unsubstituted' carbon-chain molecule C{sub 4}H and the sulfur-bearing molecules SO and HCS{sup +} were determined from detected lines in L1527.

• OSTI ID: 22004217
• Journal Information: Astrophysical Journal, Vol. 744, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACETONITRILE
CARBON
HYDROXIDES
METHANOL
MICROWAVE RADIATION
SPECTROSCOPY
STAR EVOLUTION
STARS
TELESCOPES