TY - JOUR
T1 - A new FUSE survey of interstellar HD
AU - Snow, Theodore P.
AU - Ross, Teresa L.
AU - Destree, Joshua D.
AU - Drosback, Meredith M.
AU - Jensen, Adam G.
AU - Rachford, Brian L.
AU - Sonnentrucker, Paule
AU - Ferlet, Roger
PY - 2008/12/1
Y1 - 2008/12/1
N2 - We have used archival FUSE data to complete a survey of interstellar HD in 41 lines of sight with a wide range of extinctions. This follow-up to an earlier survey was made to further assess the utility of HD as a cosmological probe; to analyze the HD formation process; and to see what trends with other interstellar properties were present in the data. We employed the curve-of-growth method, supported by line profile fitting, to derive accurate column densities of HD. We find that the N(HD)/2N(H2) ratio is substantially lower than the atomic D/H ratio and conclude that the molecular ratio has no bearing on cosmology, because local processes are responsible for the formation of HD. Based on correlations with E(B -V), H2, CO, and iron depletion, we find that HD is formed in the densest portion of the clouds; the slope of the log N(HD)/log N(H2) correlation is greater than 1.0, caused by the destruction rate of HD declining more slowly than that of H 2; and, as a sidelight, that the depletions are density dependent.
AB - We have used archival FUSE data to complete a survey of interstellar HD in 41 lines of sight with a wide range of extinctions. This follow-up to an earlier survey was made to further assess the utility of HD as a cosmological probe; to analyze the HD formation process; and to see what trends with other interstellar properties were present in the data. We employed the curve-of-growth method, supported by line profile fitting, to derive accurate column densities of HD. We find that the N(HD)/2N(H2) ratio is substantially lower than the atomic D/H ratio and conclude that the molecular ratio has no bearing on cosmology, because local processes are responsible for the formation of HD. Based on correlations with E(B -V), H2, CO, and iron depletion, we find that HD is formed in the densest portion of the clouds; the slope of the log N(HD)/log N(H2) correlation is greater than 1.0, caused by the destruction rate of HD declining more slowly than that of H 2; and, as a sidelight, that the depletions are density dependent.
KW - ISM: abundances
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U2 - 10.1086/592288
DO - 10.1086/592288
M3 - Article
AN - SCOPUS:56849093900
SN - 0004-637X
VL - 688
SP - 1124
EP - 1136
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -