TY  - JOUR
A1  - Gvaramadze, Vasily V.
A1  - Fabrika, Sergei Nikolaevich
A1  - Hamann, Wolf-Rainer
A1  - Sholukhova, Olga N.
A1  - Valeev, Azamat F.
A1  - Goranskij, Vitaly P.
A1  - Cherepashchuk, Anatol M.
A1  - Bomans, Dominik J.
A1  - Oskinova, Lida
T1  - Discovery of a new Wolf-Rayet star and its ring nebula in Cygnus
N2  - We report the serendipitous discovery of a ring nebula around a candidate Wolf-Rayet (WR) star, HBHA 4202-22, in Cygnus using the Spitzer Space Telescope archival data. Our spectroscopic follow-up observations confirmed the WR nature of this star (we named it WR 138a) and showed that it belongs to the WN8-9h subtype. We thereby add a new example to the known sample of late WN stars with circumstellar nebulae. We analysed the spectrum of WR 138a by using the Potsdam Wolf-Rayet (PoWR) model atmospheres, obtaining a stellar temperature of 40 kK. The stellar wind composition is dominated by helium with 20 per cent of hydrogen. The stellar spectrum is highly reddened and absorbed (EB- V = 2.4 mag, A(V) = 7.4 mag). Adopting a stellar luminosity of log L/L-circle dot = 5.3, the star has a mass-loss rate of 10-4.7 M- circle dot yr-1, and resides in a distance of 4.2 kpc. We measured the proper motion for WR 138a and found that it is a runaway star with a peculiar velocity of similar or equal to 50 km s-1. Implications of the runaway nature of WR 138a for constraining the mass of its progenitor star and understanding the origin of its ring nebula are discussed.
Y1  - 2009
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/31683
UR  - http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0035-8711
SN  - 0035-8711
ER  -