MONOS: Multiplicity Of Northern O-type Spectroscopic systems

Abstract

Context. Multiplicity in massive stars is key to understanding the chemical and dynamical evolution of galaxies. Among massive stars, those of O type play a crucial role due to their high masses and short lifetimes. Aims. MONOS (Multiplicity Of Northern O-type Spectroscopic systems) is a project designed to collect information and study O-type spectroscopic binaries with δ > −20 • . In this first paper we describe the sample and provide spectral classifications and additional information for objects with previous spectroscopic and/or eclipsing binary orbits. In future papers we will test the validity of previous solutions and calculate new spectroscopic orbits. Methods. The spectra in this paper have two sources: the Galactic O-Star Spectroscopic Survey (GOSSS), a project that obtains blueviolet R ∼ 2500 spectroscopy of thousands of massive stars, and LiLiMaRlin, a library of libraries of high-resolution spectroscopy of massive stars obtained from four different surveys (CAFÉ-BEANS, OWN, IACOB, and NoMaDS) and additional data from our own observing programs and public archives. We have also used lucky images obtained with AstraLux. Results. We present homogeneous spectral classifications for 92 O-type spectroscopic multiple systems and ten optical companions, many of them original. We discuss the visual multiplicity of each system with the support of AstraLux images and additional sources. For eleven O-type objects and for six B-type objects we present their first GOSSS spectral classifications. For two known eclipsing binaries we detect double absorption lines (SB2) or a single moving line (SB1) for the first time, to which we add a third system reported by us recently. For two previous SB1 systems we detect their SB2 nature for the first time and give their first separate spectral classifications, something we have also done for a third object just recently identified as a SB2. We also detect nine new astrometric companions and provide updated information on several others. We emphasize the results for two stars: for σ Ori AaAbB we provide spectral classifications for the three components with a single observation for the first time thanks to a lucky spectroscopy observation obtained close to the Aa,Ab periastron and for θ 1 Ori CaCb we add it to the class of Galactic Of?p stars, raising the number of its members to six. Our sample of O-type spectroscopic binaries contains more triple-or higher-order systems than double systems.

Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

“…We find wind variability in the IACOB/OWN spectroscopy, which could be partly responsible for (or caused by) the observed photometric variability. HD 37041 (O9.5 IVp, Sota et al 2011) was found to be a SB2 with a secondary B0.5 V star by Maíz Apellániz et al (2019). We find it as SB1 in the IACOB/OWN spectroscopy.…”

The R136 star cluster dissected with Hubble Space Telescope/STIS – II. Physical properties of the most massive stars in R136

“…The combined mass of the system exceeds 250 M ⊙ . Even though most stars are found in binaries or higher-order systems (Sana et al 2012(Sana et al , 2013Maíz Apellániz et al 2019), it is still possible that in some rare cases a system like Mk34 merged during the formation process or on the MS and formed a single very massive star exceeding 200 M ⊙ .…”

Radial velocity measurements of the runaway stars AE Aur and ι Ori

“…As AE Aur and ι Ori are both early‐type stars with spectral types of O 9.5 V (Sota et al 2011) and O 8.5 III (Maíz Apellániz et al 2019), their RVs were determined by measuring the wavelengths of the neutral helium lines (He I) at 4713.15, 4921.93, and 5015.68 Å, which were selected based on their prominence in the fully reduced FLECHAS spectra of both stars, the spectral energy distribution of the observed targets, and the spectral sensitivity of the used instrument, respectively.…”