TY  - JOUR
A1  - Toala, Jesus A.
A1  - Oskinova, Lida
A1  - Hamann, Wolf-Rainer
A1  - Ignace, Richard
A1  - Sander, Andreas Alexander Christoph
A1  - Shenar, Tomer
A1  - Todt, Helge Tobias
A1  - Chu, Y. -H.
A1  - Guerrero, Martin A.
A1  - Hainich, Rainer
A1  - Torrejon, Jose Miguel
T1  - On the Apparent Absence of Wolf-Rayet plus Neutron Star Systems
BT  - the Curious Case of WR124
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - Among the different types of massive stars in advanced evolutionary stages is the enigmatic WN8h type. There are only a few Wolf-Rayet (WR) stars with this spectral type in our Galaxy. It has long been suggested that WN8h-type stars are the products of binary evolution that may harbor neutron stars (NS). One of the most intriguing WN8h stars is the runaway WR 124 surrounded by its magnificent nebula M1-67. We test the presence of an accreting NS companion in WR 124 using similar to 100 ks long observations by the Chandra X-ray observatory. The hard X-ray emission from WR 124 with a luminosity of L-X similar to 10(31) erg s(-1) is marginally detected. We use the non-local thermodynamic equilibrium stellar atmosphere code PoWR to estimate the WR wind opacity to the X-rays. The wind of a WN8-type star is effectively opaque for X-rays, hence the low X-ray luminosity of WR 124 does not rule out the presence of an embedded compact object. We suggest that, in general, high-opacity WR winds could prevent X-ray detections of embedded NS, and be an explanation for the apparent lack of WR+NS systems.
KW  - circumstellar matter
KW  - ISM: jets and outflows
KW  - stars: massive
KW  - stars: evolution
KW  - stars: neutron
KW  - stars: Wolf-Rayet
Y1  - 2018
U6  - https://doi.org/10.3847/2041-8213/aaf39d
SN  - 2041-8205
SN  - 2041-8213
VL  - 869
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -