8,597 research outputs found
UBVRI CCD photometry of the OB associations Bochum 1 and Bochum 6
We report the first deep CCD photometry of 2460 stars in the field of
two poorly studied OB associations Bochum 1 and Bochum 6. We selected 15 and 14
probable members in Bochum 1 and Bochum 6 respectively using photometric
criteria and proper motion data of Tycho 2. Our analysis indicates variable
reddening having mean value of 0.470.10 and 0.710.13 mag
for Bochum 1 and Bochum 6 respectively. Using the zero-age main-sequence
fitting method, we derive a distance of 2.80.4 and 2.50.4 Kpc for
Bochum 1 and Bochum 6 respectively. We obtain an age of 105 Myrs for both
the associations from isochrone fitting. In both associations high and low mass
stars have probably formed together. Within the observational uncertainties,
mass spectrum of the both associations appears to be similar to the Salpeter's
one.Comment: 14 pages, 7 figures, 6 tables. Accepted for Bull. Astr. Soc. Indi
Non-uniform extinction in young open star clusters
The extinction law and the variation of colour excess with position,
luminosity as well as spectral class in young open star clusters NGC 663,
NGC869, NGC 884, NGC 1502, NGC 1893, NGC 2244, NGC 2264, NGC 6611, Tr 14, Tr
15,Tr 16, Coll 228, Tr 37 and Be 86 have been studied. The difference in the
minimum and maximum values of E(B-V) of cluster members has been considered as
a measure of the presence of non-uniform gas and dust inside the clusters. Its
value ranges from 0.22 to 1.03 mag in clusters under study, which indicates
that non-uniform extinction is present in all the clusters. It has been noticed
for the first time in NGC 1502 and Tr 37. It is also found that the
differential colour excess in open clusters, which may be due to the presence
of gas and dust, decreases systematically with the age of clusters indicating
that matter is used either in star formation or blown away by hot stars or
both. There is no uniformity in the variation of E(B-V) with either position or
spectral class or luminosity.Comment: 11 pages, 8 figures, 4 tables; accepted for publication in MNRAS,
typos adde
and bifurcations in rotational bands of diatomic molecules
It is shown that the recently observed bifurcation seen in
superdeformed nuclear bands is also occurring in rotational bands of diatomic
molecules. In addition, signs of a bifurcation, of the same order
of magnitude as the one, are observed both in superdeformed
nuclear bands and rotational bands of diatomic molecules.Comment: LaTex twice, 10 pages and 5 PS figures provided upon demand by the
Author
Pre-treatment loss to follow-up among smear-positive pulmonary tuberculosis cases: a 10-year audit of national data from Fiji
- …