Massive Stars in Molecular Clouds Rich in High-energy Sources: The Bridge of G332.809-0.132 and CS 78 in NGC 6334. (arXiv:2007.11074v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Messineo_M/0/1/0/all/0/1">Maria Messineo</a> (University of Science and Technology of China), <a href="http://arxiv.org/find/astro-ph/1/au:+Menten_K/0/1/0/all/0/1">Karl M. Menten</a> (Max-Planck-Institut fuer Radioastronomie), <a href="http://arxiv.org/find/astro-ph/1/au:+Figer_D/0/1/0/all/0/1">Donald F. Figer</a> (Rochester Institute of Technology), <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_J/0/1/0/all/0/1">J. Simon Clark</a> (The Open University)
Detections of massive stars in the direction of the H II region CS 78 in NGC
6334 and of G332.809-0.132 are here presented. The region covered by the
G332.809-0.132 complex coincides with the RCW 103 stellar association. In its
core (40′ in radius), approximately 110 OB candidate stars (Ks < 10 mag and 0.4
< AKs < 1.6 mag) were identified using 2MASS, DENIS, and GLIMPSE data. This
number of OB stars accounts for more than 50% of the observed number of Lyman
continuum photons from this region. Medium-resolution K-band spectra were
obtained for seven early types, including one WN 8 star and one Ofpe/WN 9 star;
the latter is located near the RCW 103 remnant and its luminosity is consistent
with a distance of about 3 kpc. The area analyzed encloses 9 of the 34 OB stars
previously known in RCW 103, as well as IRAS 16115-5044, which we reclassify as
a candidate luminous blue variable. The line of sight is particularly
interesting, crossing three spiral arms; a molecular cloud at -50 (with RCW 103
in the Scutum-Crux arm) and another at -90 km s-1 (in the Norma arm) are
detected, both rich in massive stars and supernova remnants. We also report the
detection of a B supergiant as the main ionizing source of CS 78, 2MASS
J17213513-3532415. Medium-resolution H and K band spectra display H I and He I
lines, as well as Fe II lines. By assuming a distance of 1.35 kpc, we estimate
a bolometric magnitude of -6.16, which is typical of supergiants.
Detections of massive stars in the direction of the H II region CS 78 in NGC
6334 and of G332.809-0.132 are here presented. The region covered by the
G332.809-0.132 complex coincides with the RCW 103 stellar association. In its
core (40′ in radius), approximately 110 OB candidate stars (Ks < 10 mag and 0.4
< AKs < 1.6 mag) were identified using 2MASS, DENIS, and GLIMPSE data. This
number of OB stars accounts for more than 50% of the observed number of Lyman
continuum photons from this region. Medium-resolution K-band spectra were
obtained for seven early types, including one WN 8 star and one Ofpe/WN 9 star;
the latter is located near the RCW 103 remnant and its luminosity is consistent
with a distance of about 3 kpc. The area analyzed encloses 9 of the 34 OB stars
previously known in RCW 103, as well as IRAS 16115-5044, which we reclassify as
a candidate luminous blue variable. The line of sight is particularly
interesting, crossing three spiral arms; a molecular cloud at -50 (with RCW 103
in the Scutum-Crux arm) and another at -90 km s-1 (in the Norma arm) are
detected, both rich in massive stars and supernova remnants. We also report the
detection of a B supergiant as the main ionizing source of CS 78, 2MASS
J17213513-3532415. Medium-resolution H and K band spectra display H I and He I
lines, as well as Fe II lines. By assuming a distance of 1.35 kpc, we estimate
a bolometric magnitude of -6.16, which is typical of supergiants.
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