Pablo Martín-Ravelo | Searcharxiv

arXiv2024

The YMDB catalog: Young massive detached binaries for the determination of high-precision absolute stellar parameters

Massive stars play a crucial role in the cosmic dynamics and chemical evolution of galaxies, however our understanding of their evolution and properties remains limited. An accurate determination of stellar parameters is essential for advancing our knowledge. Detached eclipsing binaries (DEBs) are particularly valuable for these determinations due to the minimal interaction between their stellar components, allowing for precise measurements. This study introduces the Young Massive Detached Binary (YMDB) catalog, designed to address the gap in the high-precision absolute parameter determination for young massive stars. By focusing on DEBs within the spectral range O9-B1, this catalog seeks to provide a reliable database for future studies and improve our understanding of massive star evolution. We conducted a photometric analysis of 87 young massive stars in DEBs using TESS light curves (LCs) that were processed through a custom pipeline. This analysis involved determining the amplitude of magnitude variations, orbital periods, times of minima, eccentricities, and the presence of apsidal motion and heartbeat phenomena. A thorough literature review was performed to obtain MK spectral classifications. We performed our own spectral classification of 19 systems to support the sample where a new classification was lacking or inconclusive. The analysis identified 20 previously unreported binary systems, with 13 newly recognized as variables. Among the 87 stars examined, 30 are confirmed as YMDB members, and 25 are candidates pending spectral classification. The remaining 32 stars belong to unsuitable spectral types or nondetached binary nature. Notable findings include the identification of new LC classifications, eccentricities in 13 systems, and heartbeat phenomena in several targets. The YMDB catalog offers a resource of high-quality LCs and reliable stellar classifications.

astro-ph.SR↗

arXiv2022

The winking eye of a very massive star: WR 21a revealed as an eclipsing binary by TESS

WR~21a was known as a massive spectroscopic binary composed of an O2.5 If*/WN6ha primary and an O3 V((f*))z secondary. Although a minimum value, the mass estimated for the primary placed it as one of the most massive stars found in our Galaxy. We report the discovery of photometric variations in the time series observations carried out by the Transiting Exoplanet Survey Satellite (TESS). These light variations are interpreted as formed by two main components: a sharp partial eclipse of the O3 secondary by the O2.5/WN6 star, and tidally excited oscillations. Based on the light minima a new ephemeris for the system is calculated. The system configuration is detached and the observed eclipse corresponds to the periastron passage. During the eclipse, the light curve shape suggests the presence of the heartbeat effect. The frequencies derived for the tidally excited oscillations are harmonics of the orbital period. Combining new and previously published radial velocity measurements, a new spectroscopic orbital solution is also obtained. Using the \textsc{phoebe} code we model the \textit{TESS} light curve and determine stellar radii of $R_{\rm O2.5/WN6}=23.4$ R$_\odot$ and $R_{\rm O3}=14.3$ R$_\odot$ and an orbital inclination $i=62^\circ\!\!.2\pm0^\circ\!\!.9$. The latter combined with the spectroscopic minimum masses lead to absolute masses of $M_{\rm O2.5/WN6}=93.2$ M$_\odot$ and $M_{\rm O3}=52.9$ M$_\odot$, which establishes WR21a as belonging to the rare group of the very massive stars.

astro-ph.SR↗