Publication details
Everything that glitters is not gold: V1315 Cas is not a dormant black hole
| Authors | |
|---|---|
| Year of publication | 2023 |
| Type | Article in Periodical |
| Magazine / Source | Monthly Notices of the Royal Astronomical Society |
| MU Faculty or unit | |
| Citation | |
| Web | https://doi.org/10.1093/mnras/stad2137 |
| Doi | http://dx.doi.org/10.1093/mnras/stad2137 |
| Keywords | techniques: radial velocities; techniques: spectroscopic; binaries: general; binaries: spectroscopic; stars: variables: general |
| Description | 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 P-orb = 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 +/- 0.03 M-circle dot and R-p = 18.51(-0.07)(+0.12) R-circle dot; for the secondary, M-s = 7.3 +/- 0.3 M-circle dot and R-s = 4.02(-2.0)(+2.3) R-circle dot. Modelling the evolution of the system with MESA, we found an age of similar to 7.7 x 10(7) 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 aemission suggest the presence of a circumstellar or circumbinary disc. V1315 Cas will likely become a detached stripped star binary. |