Spectroscopic and photometric analysis of the early-type spectroscopic binary HD 161853 in the centre of an H II

GAMEN, R. C.; PUTKURI, C.; MORRELL, N. I.; BARBÁ, R.; ARIAS, J.; MAÍZ APELLÁNIZ, J.; WALBORN, N. R.; SOTA, A.; ALFARO, E.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2015 vol. 584 p. 7 - 11

0004-6361

Aims. We study the O-type star HD 161853, which has been noted as aprobable double-lined spectroscopic binary system. Methods. We securedhigh-resolution spectra of HD 161853 during the past nine years. Weseparated the two components in the system and measured their respectiveradial velocities for the first time. Results. We confirm that HD 161853is an ?1 Ma old binary system consisting of an O8 V star(MA,RV ≥ 22 M⊙) and a B1-3 V star(MB,RV ≥ 7.2 M⊙) at about 1.3 kpc. From theradial velocity curve, we measure an orbital period P = 2.66765 ±0.00001 d and an eccentricity e = 0.121 ± 0.007. Its V-band lightcurve is constant within 0.014 mag and does not display eclipses, fromwhich we impose a maximum orbital inclination i = 54 deg. HD 161853 isprobably associated with an H II region and a poorly investigated veryyoung open cluster. In addition, we detect a compact emission region at50 arcsec to HD 161853 in 22 μm-WISE and 24 μm-Spitzer images,which may be identified as a dust wave piled up by the radiationpressure of the massive binary system.