We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the σ Ori Aa, Ab pair. We provided indirect arguments indicating that σ Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while σ Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the σ Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the σ Orionis cluster, the interpretation of the strong X-ray emission detected for σ Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.
Advertised on
References
It may interest you
-
The properties of blue supergiants are key for constraining the end of the main sequence phase, a phase during which massive stars spend most of their lifetimes. The lack of fast-rotating stars below 21.000K, a temperature around which stellar winds change in behaviour, has been proposed to be caused by enhanced mass-loss rates, which would spin down the star. Alternatively, the lack of fast-rotating stars may be the result of stars reaching the end of the main sequence. Here, we combine newly derived estimates of photospheric and wind parameters, wind terminal velocities from the literatureAdvertised on
-
The development of the latest generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) over recent decades has led to the discovery of new extreme astrophysical phenomena in the very-high-energy (VHE, E > 100 GeV) gamma-ray regime. Time-domain and multi-messenger astronomy are inevitably connected to the physics of transient VHE emitters, which show unexpected (and mostly unpredictable) flaring or exploding episodes at different timescales. These transients often share the physical processes responsible for the production of the gamma-ray emission, through cosmic-ray accelerationAdvertised on
-
Recent observational studies suggest that feedback from active galactic nuclei (AGNs)—the energetic centres powered by supermassive black holes—may play an important role in the formation and evolution of dwarf galaxies, contrary to the standard thought. We investigated this using two sets of 12 cosmological magnetohydrodynamic simulations of the formation of dwarf galaxies: one set using a version of the AURIGA galaxy formation physics model including AGN feedback and a parallel set with AGN feedback turned off. Our results reveal that AGNs can suppress the star formation (SF) of dwarfAdvertised on