The spectroscopic orbit of HD 168112 A,B in NGC 6604: another massive binary target for interferometry

DOI: 
10.1093/mnras/stad2657
Publication date: 
11/11/2023
Main author: 
Putkuri, C.
IAA authors: 
Sota, A.
Authors: 
Putkuri, C.;Gamen, R.;Morrell, N. I.;Maíz Apellániz, J.;Arias, J. I.;Simón-Díaz, S.;Ferrero, G. A.;Rodríguez, C. N.;Sota, A.;Benvenuto, O. G.;Barbá, R. H.
Journal: 
Monthly Notices of the Royal Astronomical Society
Publication type: 
Article
Volume: 
525
Pages: 
6084
Abstract: 
We present the first spectroscopic orbit of the O-type double-lined star HD 168112 A,B. We analyse 101 high-resolution optical spectra identifying the absorption lines of both components. The orbital solution presents a relatively long period, P = 513.52 ± 0.01 d, and a high eccentricity, e = 0.743 ± 0.005. The binary system consists of two very similar stars of minimum masses of ~25 M<SUB>⊙</SUB>, effective temperatures of ~40 000 K, and surface gravities of ~3.7 dex. The system has a minimum semimajor axis a sin i ~ 1000 R<SUB>⊙</SUB>. We confirm that the A and B visual components identified via interferometry do correspond to the spectroscopic ones. We also analyse the underlying stellar groups using Gaia DR3 data and ground-based spectroscopy as part of the Villafranca project, determining that NGC 6604 is at a distance of $1942^{+38}_{-36}$ pc and giving spectral classifications for 23 massive stellar systems in Villafranca O-035 and the surrounding Ser OB2 association, for which we provide the most complete census of massive stars to date.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023MNRAS.525.6084P/abstract
ADS Bibcode: 
2023MNRAS.525.6084P
Keywords: 
binaries: spectroscopic;stars: early-type;stars: individual: HD 168112