Bibcode
Casares, J.; González Hernández, J. I.; Israelian, G.; Rebolo, R.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 401, Issue 4, pp. 2517-2520.
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2
2010
Citations
50
Refereed citations
45
Description
We present new high-resolution spectroscopy of the low-mass X-ray binary
Cyg X-2, which enables us to refine the orbital solution and rotational
broadening of the donor star. In contrast with Elebert et al., we find a
good agreement with results reported in Casares et al. We measure P =
9.84450 +/- 0.00019 d, K2 = 86.5 +/- 1.2 kms-1 and
V sini = 33.7 +/- 0.9 kms-1. These values imply q =
M2/M1 = 0.34 +/- 0.02 and M1 = 1.71 +/-
0.21Msolar (for ). Therefore, the neutron star in Cyg X-2 can
be more massive than canonical. We also find no evidence for irradiation
effects in our radial velocity curve which could explain the discrepancy
between Elebert et al.'s and our K2 values.
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