TY - JOUR
T1 - HD 148937
T2 - A multiwavelength study of the third galactic member of the of?p class
AU - Nazé, Yaël
AU - Walborn, Nolan R.
AU - Rauw, Gregor
AU - Martins, Fabrice
AU - Pollock, A. M.T.
AU - Bond, Howard E.
PY - 2008/5/1
Y1 - 2008/5/1
N2 - Three Galactic O-type stars belong to the rare class of Of?p objects: HD 108, HD 191612, and HD 148937. The first two stars show a wealth of phenomena, including strong X-ray emission, light variability, and dramatic periodic spectral variability. We present here the first detailed optical and X-ray study of the third Galactic Of?p star, HD 148937. Spectroscopic monitoring has revealed low-level variability in the Balmer and He II λ4686 lines, but constancy at He I and C III λ4650. The Hα line exhibits profile variations at a possible periodicity of 7 days. Model atmosphere fits yield T eff = 41000 2000 K, log(g) = 4.0 0.1, M ⊙ yr -1, and an overabundance of nitrogen by a factor of 4. At X-ray wavelengths, HD 148937 resembles HD 108 and HD 191612 in having a thermal spectrum dominated by a relatively cool component (kT = 0.2 keV), broad lines (≥1700 km s-1), and an order-of-magnitude overluminosity compared to normal O stars (log[L unabs X/L BOL] -6).
AB - Three Galactic O-type stars belong to the rare class of Of?p objects: HD 108, HD 191612, and HD 148937. The first two stars show a wealth of phenomena, including strong X-ray emission, light variability, and dramatic periodic spectral variability. We present here the first detailed optical and X-ray study of the third Galactic Of?p star, HD 148937. Spectroscopic monitoring has revealed low-level variability in the Balmer and He II λ4686 lines, but constancy at He I and C III λ4650. The Hα line exhibits profile variations at a possible periodicity of 7 days. Model atmosphere fits yield T eff = 41000 2000 K, log(g) = 4.0 0.1, M ⊙ yr -1, and an overabundance of nitrogen by a factor of 4. At X-ray wavelengths, HD 148937 resembles HD 108 and HD 191612 in having a thermal spectrum dominated by a relatively cool component (kT = 0.2 keV), broad lines (≥1700 km s-1), and an order-of-magnitude overluminosity compared to normal O stars (log[L unabs X/L BOL] -6).
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U2 - 10.1088/0004-6256/135/5/1946
DO - 10.1088/0004-6256/135/5/1946
M3 - Article
AN - SCOPUS:50849103383
SN - 0004-6256
VL - 135
SP - 1946
EP - 1957
JO - Astronomical Journal
JF - Astronomical Journal
IS - 5
ER -