Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2011-02-16
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
9 pages, 4 figures. Accepted for publication in MNRAS
Scientific paper
We report near-infrared radial velocity measurements of the recently identified donor star in the high mass X-ray binary system OAO 1657-415 obtained in the H band using ISAAC on the VLT. Cross-correlation methods were employed to construct a radial velocity curve with a semi-amplitude of $22.1 \pm 3.5$ km s$^{-1}$. Combined with other measured parameters of this system this provides a dynamically determined neutron star mass of $1.42 \pm 0.26 M$_{\odot}$ and a mass of $14.3 \pm 0.8 M$_{\odot}$ for the Ofpe/WN9 highly evolved donor star. OAO 1657-415 is an eclipsing High Mass X-ray binary pulsar with the largest eccentricity and orbital period of any within its class. Of the ten known eclipsing X-ray binary pulsars OAO 1657-415 becomes the ninth with a dynamically determined neutron star mass solution and only the second in an eccentric system. Furthermore, the donor star in OAO 1657-415 is much more highly evolved than the majority of the supergiant donors in other High Mass X-ray binaries (HMXBs), joining a small but growing list of HMXBs donors with extensive hydrogen depleted atmospheres. Considering the evolutionary development of OAO 1657-415, we have estimated the binding energy of the envelope of the mass donor and find that there is insufficient energy for the removal of the donor's envelope via spiral-in, ruling out a Common Envelope evolutionary scenario. With its non-zero eccentricity and relatively large orbital period the identification of a definitive evolutionary pathway for OAO1657-415 remains problematic, we conclude by proposing two scenarios which may account for OAO1657-415 current orbital configuration.
Clark Simon J.
Crowther Paul A.
Langer Norbert
Mason A. B.
Negueruela Ignacio
No associations
LandOfFree
The evolution and masses of the neutron star and donor star in the high mass X-ray binary OAO 1657-415 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The evolution and masses of the neutron star and donor star in the high mass X-ray binary OAO 1657-415, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The evolution and masses of the neutron star and donor star in the high mass X-ray binary OAO 1657-415 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-417419