A SURVEY OF C4H, C6H, AND C6H- WITH THE GREEN BANK TELESCOPE

被引：60

作者：

Gupta, H. ^{[1
,2
,3
,4
]}

Gottlieb, C. A. ^{[1
,2
]}

McCarthy, M. C. ^{[1
,2
]}

Thaddeus, P. ^{[1
,2
]}

机构：

[1] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[2] Harvard Univ, Sch Engn & Appl Sci, Cambridge, MA 02138 USA

[3] Univ Texas Austin, Inst Theoret Chem, Dept Chem, Austin, TX 78712 USA

[4] Univ Texas Austin, Inst Theoret Chem, Dept Biochem, Austin, TX 78712 USA

来源：

ASTROPHYSICAL JOURNAL | 2009年 / 691卷 / 02期

关键词：

ISM: molecules; molecular data; molecular processes; radio lines: ISM; DENSE INTERSTELLAR CLOUDS; MASS PROTOSTAR IRAS-04368+2557; MOLECULAR LINE OBSERVATIONS; EVOLVED STARLESS CORE; IONIZATION FRACTION; NEGATIVE-IONS; ASTRONOMICAL DETECTION; DARK CLOUDS; IRC+10 216; CHEMISTRY;

D O I：

10.1088/0004-637X/691/2/1494

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

A survey of the carbon chain negative ion C6H- and the structurally similar radicals C4H and C6H has been done with the 100 m Green Bank Telescope toward 24 galactic molecular sources. The most readily observed molecular anion to date, C6H- was detected in two new sources: the dark clouds L1544 and L1521F, where it was found to be present at the level of 2.5% +/- 0.8% and 4% +/- 1%, respectively relative to neutral C6H. C4H was detected in nearly all dark clouds surveyed ( in six for the first time), and C6H was detected in five dark clouds and one translucent cloud. The observed C6H-/C6H( 1%-4%) and C6H/C4H(0.2%-1%) ratios in these sources suggest that C6H- may be close to detection in many other dark clouds. The fractional ionization derived from the C6H-/C6H ratio in L1544 and L1521F of 10(-8) to 10(-7) is comparable to earlier estimates from positive molecular ions.

引用

页码：1494 / 1500

页数：7

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