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Optical spectroscopy of X-MEGA targets I. CPD -59 2635: A New Double-Lined O type Binary in the Carina Nebula

J. F. Albacete Colombo·N. I. Morrell·V. S. Niemela·M. F. Corcoran
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Abstract

Optical spectroscopy of CPD -59 2635, one of the O-type stars in the open cluster Trumpler 16 in the Carina Nebula, reveals this star to be a double-lined binary system. We have obtained the first radial velocity orbit for this system, consisting of a circular solution with a period of 2.2999 days and semi amplitudes of 208 and 273 km/s. This results in minimum masses of 15 and 11 Msol for the binary components of CPD -59 2635, which we classified as O8V and O9.5V, though spectral type variations of the order of 1 subclass, that we identify as the Struve-Sahade effect, seem to be present in both components. From ROSAT HRI observations of CPD -59 2635 we determine a luminosity ratio log(L_x/L_bol)~ -7, which is similar to that observed for other O-type stars in the Carina Nebula region. No evidence of light variations is present in the available optical or X-rays data sets.

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J. F. Albacete Colombo, N. I. Morrell, V. S. Niemela, M. F. Corcoran. 2001-05-01. Optical spectroscopy of X-MEGA targets I. CPD -59 2635: A New Double-Lined O type Binary in the Carina Nebula. https://doi.org/10.1046/j.1365-8711.2001.04497.x

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