Everything that glitters is not gold: V1315 Cas is not a dormant black hole

Zak, J.; Jones, D.; Boffin, H. M. J.; Beck, P. G.; Klencki, J.; Bodensteiner, J.; Shenar, T.; Van Winckel, H.; Skarka, M.; Arellano-Córdova, K.; Viuho, J.; Sowicka, P.; Guenther, E. W.; Hatzes, A.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society

Advertised on:
Number of authors
IAC number of authors
Refereed citations
The quest for quiet or dormant black holes has been ongoing since several decades. Ellipsoidal variables possibly indicate the existence of a very high-mass invisible companion and are thought to be one of the best ways to find such dormant black holes. This, however, is not a panacea as we show here with one example. We indeed report the discovery of a new semidetached interacting binary, V1315 Cas, discovered as an ellipsoidal variable. Using data from photometric surveys (ASAS-SN, TESS) and high-resolution spectroscopy, we derived a nearly circular orbit with an orbital period of Porb = 34.54 d. The binary system consists of an evolved F-type star primary that is likely still filling its Roche lobe and a B-type star secondary. Using PHOEBE2, we derived the following masses and radii: for the primary, $M_p =0.84 \pm 0.03 \, \rm {M}_{\odot}$ and $R_p =18.51^{+0.12}_{-0.07} \, \rm {R}_{\odot}$; for the secondary, $M_s =7.3 \pm 0.3 \, \rm {M}_{\odot}$ and $R_s =4.02^{+2.3}_{-2.0}\, \rm {R}_{\odot}$. Modelling the evolution of the system with MESA, we found an age of ~7.7 × 107 yr. The system is at the end of a period of rapid non-conservative mass transfer that reversed its mass ratio, while significantly widening its orbit. The primary shows carbon depletion and nitrogen overabundance, indicative of CNO-processed material being exposed due to mass transfer. An infrared excess and stationary H α emission suggest the presence of a circumstellar or circumbinary disc. V1315 Cas will likely become a detached stripped star binary.
Related projects
Izquierda - Imagen RGB de la nebulosa de Orión y M43 obtenida filtros estrechos con la cámara WFC en el INT: H alfa (rojo), [S II] 6716+30 (verde), [O III] 5007 (azul). Derecha - Imagen en falso color de la nebulosa planetaria NGC 6778. En azul se ve la emisión en la línea de O II tomada con el filtro sintonizable azul del instrumento OSIRIS en el GTC; en verde imagen con el filtro estrecho de [O III] del Nordic Optical Telescope (NOT).
Physics of Ionized Nebulae
The research that is being carried out by the group can be condensed into two main lines: 1) Study of the structure, dynamics, physical conditions and chemical evolution of Galactic and extragalactic ionized nebulae through detailed analysis and modelization of their spectra. Investigation of chemical composition gradients along the disk of our
García Rojas
Helio and Asteroseismology
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary