DISCOVERY OF A COMPACT COMPANION TO THE HOT SUBDWARF STAR BD +37 Degree-Sign 442

We report the results of the first X-ray observation of the luminous and helium-rich O-type subdwarf BD +37 Degree-Sign 442 carried out with the XMM-Newton satellite in 2011 August. X-ray emission is detected with a flux of about 3 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} (0.2-1 keV)...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2012-05, Vol.750 (2)
Main Authors: La Palombara, Nicola, Mereghetti, Sandro, Tiengo, Andrea, Esposito, Paolo
Format: Article
Language:English
Subjects:
ASTRONOMY
ASTROPHYSICS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COSMIC PHOTONS
COSMIC X-RAY SOURCES
EV RANGE
HELIUM
INDEXES
KEV RANGE
NEUTRON STARS
PHOTON EMISSION
PULSARS
PULSATIONS
SATELLITES
STELLAR WINDS
WHITE DWARF STARS
X RADIATION
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Summary:We report the results of the first X-ray observation of the luminous and helium-rich O-type subdwarf BD +37 Degree-Sign 442 carried out with the XMM-Newton satellite in 2011 August. X-ray emission is detected with a flux of about 3 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} (0.2-1 keV) and a very soft spectrum, well fit by the sum of a blackbody with temperature kT{sub BB} = 45{sup +11}{sub -9} eV, and a power law with a poorly constrained photon index. Significant pulsations with a period of 19.2 s are detected, indicating that the X-ray emission originates in a white dwarf or neutron star companion, most likely powered by accretion from the wind of BD +37 Degree-Sign 442.
ISSN:2041-8205
2041-8213
DOI:10.1088/2041-8205/750/2/L34