Physical parameters and long-term photometric variability of V1481 Ori, an SB2 member of Orion nebula Cluster with an accreting component

MESSINA, SergioSergioMESSINAParihar, P.P.PariharBIAZZO, KatiaKatiaBIAZZOLANZA, Antonino FrancescoAntonino FrancescoLANZADISTEFANO, Elisa Maria CarmelaElisa Maria CarmelaDISTEFANOMelo, C. H. F.C. H. F.MeloBradstreet, D. H.D. H.BradstreetHerbst, W.W.Herbst2020-05-042020-05-0420160035-8711http://hdl.handle.net/20.500.12386/24462We present the results of our analysis on V1481 Ori (JW 239), a young SB2 in the Orion nebula Cluster with a circumbinary disc accreting on the lower mass component. The analysis is based on high-resolution spectroscopic data and high-quality photometric time series about 20-yr long. Thanks to the spectroscopy, we confirm the binary nature of this system consisting of M3 + M4 components and derive the mass ratio MB/MA = 0.54, a variable luminosity ratio LB/LA = 0.68-0.94, and an orbital period Porb = 4.433 d. The photometric data allowed us to measure the rotation periods of the two components Pphot = 4.4351 d and they are found to be synchronized with the orbital period. The simultaneous modelling of V-, I-band, and radial velocity curves in the 2005 season suggests that the variability is dominated by one hotspot on the secondary component covering at least ∼3.5 per cent of the stellar surface and about 420 K hotter than the unperturbed photosphere. Such a spot may originate from the material of the circumbinary disc accreting on to the secondary component. We also detect an apparent 6-yr periodic variation in the position of this hotspot, which is inferred from the phase migration of the light-curve maximum, which we interpret as due to either the presence of surface differential rotation as large as 0.065 per cent, a value compatible with the fully convective components, or to a periodic exchange of angular momentum between the disc and the star, which implies a minimum magnetic field strength of 650 G at the stellar surface.STAMPAenPhysical parameters and long-term photometric variability of V1481 Ori, an SB2 member of Orion nebula Cluster with an accreting componentArticle10.1093/mnras/stv30002-s2.0-84976884453000373583900081https://academic.oup.com/mnras/article/457/3/3372/25888842016MNRAS.457.3372MFIS/05 - ASTRONOMIA E ASTROFISICAScienze Fisiche Settori ERC (ERC) di riferimento::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation