2007ApJ...667.1002S


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.11CET14:34:20

2007ApJ...667.1002S - Astrophys. J., 667, 1002-1016 (2007/October-1)

Hubble Space Telescope survey of interstellar 12CO/13CO in the solar neighborhood.

SHEFFER Y., ROGERS M., FEDERMAN S.R., LAMBERT D.L. and GREDEL R.

Abstract (from CDS):

We examine 20 diffuse and translucent Galactic sight lines and extract the column densities of the 12CO and 13CO isotopologues from their ultraviolet A-X absorption bands detected in archival Space Telescope Imaging Spectrograph data with λ/Δλ≥46,000. Five more targets with Goddard High-Resolution Spectrograph data are added to the sample that more than doubles the number of sight lines with published Hubble Space Telescope observations of 13CO. Most sight lines have 12CO-to-13CO isotopic ratios that are not significantly different from the local value of 70 for 12C/13C, which is based on millimeter-wave observations of rotational lines in emission from CO and H2 CO inside dense molecular clouds, as well as on results from optical measurements of CH+. Five of the 25 sight lines are found to be fractionated toward lower 12C/13C values, while three sight lines in the sample are fractionated toward higher ratios, signaling the predominance of either isotopic charge exchange or selective photodissociation, respectively. There are no obvious trends of the 12CO-to-13CO ratio with physical conditions such as gas temperature or density, yet 12CO/13CO does vary in a complicated manner with the column density of either CO isotopologue, owing to varying levels of competition between isotopic charge exchange and selective photodissociation in the fractionation of CO. Finally, rotational temperatures of H2 show that all sight lines with detected amounts of 13CO pass through gas that is on average colder by 20 K than the gas without 13CO. This colder gas is also sampled by CN and C2molecules, the latter indicating gas kinetic temperatures of only 28 K, enough to facilitate an efficient charge exchange reaction that lowers the value of 12CO/13CO.

Abstract Copyright:

Journal keyword(s): ISM: Abundances - ISM: Molecules - Ultraviolet: ISM

Simbad objects: 39

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Number of rows : 39

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 RAFGL 490 Y*O 03 27 38.7928323987 +58 47 00.017662871           ~ 334 0
2 HD 21483 * 03 28 46.6535161214 +30 22 31.233721714 7.080 7.390 7.070     B3III 134 0
3 * o Per * 03 42 22.6455526 +33 57 54.089323 4.13 4.912 4.972     B0.5V 279 0
4 * omi Per ** 03 44 19.13204 +32 17 17.6929 3.13 3.88 3.83 3.71 3.71 B1III 572 0
5 HD 23478 Be* 03 46 40.8705296076 +32 17 24.691744639 6.17 6.708 6.671     B3IV 127 0
6 * zet Per V* 03 54 07.9224751 +31 53 01.081262 2.19 2.97 2.85 2.71 2.62 B1Ib 810 0
7 V* X Per HXB 03 55 23.0778791365 +31 02 45.045745259 6.090 6.840 6.720     O9.5III 898 0
8 4C 50.11 QSO 03 59 29.74726473 +50 57 50.1615765           ~ 389 1
9 * 62 Tau * 04 23 59.7629429746 +24 18 03.527426906 6.18 6.499 6.337     B 185 0
10 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1436 1
11 M 42 HII 05 35 17.3 -05 23 28           ~ 3664 0
12 NAME Mon R2 IRS 3 Y*O 06 07 47.8 -06 22 55           ~ 133 0
13 HD 96675 pr* 11 05 57.8104415475 -76 07 48.883424761   7.82 7.68   8.48 B6IV/V 68 0
14 HD 99872 * 11 28 18.41395 -72 28 26.3265 5.83 6.221 6.115     B4/5V 70 1
15 V* V760 Sco Al* 16 24 43.7186408435 -34 53 37.535017356   7.16 7.05     B4V 140 0
16 * rho Oph C Ro* 16 25 35.0836168833 -23 24 18.788751256 7.24 7.59 7.27     B5V 103 0
17 * rho Oph A * 16 25 35.142 -23 26 49.90 4.3 5.22 5.05     B2/3V 382 0
18 * chi Oph Be* 16 27 01.4349892 -18 27 22.493784 3.95 4.71 4.43 3.97 3.73 B2Vne 561 0
19 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 2944 0
20 HD 148937 SB* 16 33 52.3867163783 -48 06 40.476619334 6.49 7.12 6.71 7.61   O6f?p 349 4
21 * zet Oph Be* 16 37 09.5390545 -10 34 01.529471 1.73 2.58 2.56 2.46 2.50 O9.2IVnn 1710 2
22 HD 154368 s*b 17 06 28.3687923960 -35 27 03.759955171 6.10 6.63 6.13 7.12   O9.5Iab 261 0
23 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11083 0
24 GCIRS 9 LP* 17 45 40.447 -29 00 34.49           M3III 98 0
25 HD 177989 * 19 07 37.7606873326 -18 43 34.508944384 8.39 9.22 9.34     B2II 83 0
26 HD 192035 * 20 10 49.5883177788 +47 48 47.195114241 7.41 8.26 8.22     B0III-IV(n) 51 1
27 HD 198781 * 20 49 17.3908439894 +64 02 32.125046483 5.75 6.472 6.451     B0.5V 89 0
28 HD 203374 Be* 21 19 07.3841340802 +61 51 30.296427340 6.23 6.908 6.674     B0IVpe 117 0
29 HD 203532 * 21 33 54.5737752124 -82 40 59.110819449 6.15 6.51 6.38     B3IV/V 81 0
30 HD 206267A ** 21 38 57.61 +57 29 20.5     5.62     O6.5V((f))+O9/B0V 38 0
31 HD 206267 SB* 21 38 57.6182747705 +57 29 20.557311013 5.09 5.83 5.62   5.56 O6.0V((f))+O9:V 449 0
32 HD 207198 * 21 44 53.2790298387 +62 27 38.042162728 5.61 6.25 5.94 5.66 5.49 O8.5II 320 0
33 HD 207308 * 21 45 42.3667056382 +62 18 30.019920458 7.11 7.74 7.49     B0.5V 56 0
34 HD 207538 * 21 47 39.7898466603 +59 42 01.344202478 7 7.55 7.30     O9.7IV 176 1
35 HD 208266 * 21 53 00.3463657233 +60 38 32.644718447 7.78 8.36 8.14     B1V 44 0
36 HD 210121 * 22 08 11.9025501667 -03 31 52.770012247   7.84 7.68     B7II 146 0
37 * lam Cep s*b 22 11 30.5750839949 +59 24 52.147736074 4.55 5.29 5.05 4.77 4.62 O6.5I(n)fp 643 1
38 NGC 7538 OpC 23 13 37 +61 30.0           ~ 816 0
39 [WBN74] NGC 7538 IRS 9 Y*O 23 14 01.63 +61 27 20.2           ~ 336 0

    Equat.    Gal    SGal    Ecl

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2019.12.11-14:34:20

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