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Photometric distances to nine dark globules.

Authors :
Maheswar, G.
Bhatt, H. C.
Source :
Monthly Notices of the Royal Astronomical Society. 7/11/2006, Vol. 369 Issue 4, p1822-1836. 15p. 4 Charts, 21 Graphs.
Publication Year :
2006

Abstract

Distances to nine dark globules are determined by a method using optical ( VRI) and near-infrared (near-IR) ( JHK) photometry of stars projected towards the field containing the globules. In this method, we compute intrinsic colour indices of stars projected towards the direction of the globule by dereddening the observed colour indices using various trial values of extinction and a standard extinction law. These computed intrinsic colour indices for each star are then compared with the intrinsic colour indices of normal main-sequence stars and a spectral type is assigned to the star for which the computed colour indices best match with the standard intrinsic colour indices. Distances ( d) to the stars are determined using the and absolute magnitude corresponding to the spectral types thus obtained. A distance versus extinction plot is made and the distance at which undergoes a sharp rise is taken to be the distance to the globule. All the clouds studied in this work are in the distance range 160–400 pc. The estimated distances to dark globules LDN 544, LDN 549, LDN 567, LDN 543, LDN 1113, LDN 1031, LDN 1225, LDN 1252 and LDN 1257 are and 250 ± 50 pc, respectively. Using the distances determined, we have estimated the masses of the globules and the far-IR luminosity of the IRAS sources associated with them. The mass of the clouds studied are in the range . [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
369
Issue :
4
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
21362241
Full Text :
https://doi.org/10.1111/j.1365-2966.2006.10420.x