الشريك الخفي في سديم الرتيلاء سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2602.03650

Massive O-type stars ($$M\gtrsim15\,M_\odot$$) with an X-ray quiet black hole (BH) companion represent a crucial stage in massive binary evolution leading to binary BH mergers. The population of such binaries remains elusive, with $$\lesssim5$$ candidate or confirmed systems. The Tarantula nebula harbors thousands of massive stars, 2-3 % of which are expected to have BH companions. It is therefore an ideal place to hunt for such systems. Here we analyse 30 epochs of VLT/FLAMES IFU high-resolution observations of the H$$\delta$$ region, as well as archival FLAMES spectroscopy, of VFTS 812, a 17-day single-lined spectroscopic binary with an O4V primary and a minimum secondary mass of $$5.1\,M_\odot$$. Following careful removal of the nebular contamination, spectral disentangling on the new data did not reveal any signature of the hidden companion. We derive $$T_\mathrm{eff}=49^{+3}_{-4}$$ kK, $$\log L/L_\odot=5.7\pm0.1$$ and $$v_\mathrm{rot,max}{\rm \,sin\,}i=110^{+25}_{-35}$$ km/s for the O4V component, yielding a (single star) evolutionary mass of $$53^{+6}_{-5}$$ $$M_\odot$$ and an age in the range of 0-1.6 Myr. Using injection tests of various luminous artificial companions in our data, we exhaustively rule out the presence of any luminous signature from a main sequence star more massive than $$6\,M_\odot$$. We discuss the possible nature of the companion, suggesting that the rejuvenated O star + BH companion is the most suitable scenario to consistently explain the location, (rejuvenated) young age, eccentricity and lack of companion signature. While this establishes VFTS 812 as a strong candidate O+BH system, follow-up observations are deemed necessary for robust confirmation and to search for accretion signatures on the O4V star.