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.Comment: 44 pages, 15 figure