On the Evolutionary Stage of the Interacting Binary AU Mon

Abstract

We present a study of the evolutionary stage of the interacting binary and Double Periodic Variable AU Mon. A multi-parametric χ 2 minimization is made between the observed parameters and those predicted by the grid of non-conservative and conservative evolutionary models by Van Rensbergen et al., finding the model that best represents the current stellar and system parameters. According to this model, the system started with initial masses 4 M and 3.6 M and orbital period 3.0 days, 196 million years ago, and at present undergoes a Case-B mass-exchange episode. This evolutionary stage is consistent with the reported existence of a circumprimary accretion disk. However, the implied high mass transfer rate contrasts with the absence of significant orbital period change if the mass exchange is conservative. We show that this can occur if the system has recently entered in a non-conservative stage of mass transfer and the efficiency of mass and angular momentum loss satisfy certain conditions.

The Dynamical Mass and Evolutionary Status of the Type II Cepheid in the Eclipsing Binary System OGLE-LMC-T2CEP-211 with a Double-ring Disk* †

“…We found OGLE-LMC-T2CEP-211 to be similar to the AU Mon system (Mennickent 2014), with the exception that for OGLE-LMC-T2CEP-211 the initial period was longer and the mass transfer has finished, leaving a less massive donor on a much wider orbit around a very massive companion. The future of the AU Mon system may be similar (i.e.…”

Doppler tomography of the Double periodic variable HD 170582 at low and high stage

“…In this Section we compare the system parameters with those predicted by binary evolution models including epochs of nonconservative evolution following the method described by Mennickent (2014). The stellar and system parameters given by M15 were chosen as representative for the system, and are given in Table 2; in this paper we use subscript h and c for the hot and cool star, respectively.…”

“…The interacting binary HD 170582 (BD-14 5085, ASAS ID 183048-1447.5, α 2000 = 18:30:47.5, δ 2000 = -14:47:27.8, V = 9.66 mag, B − V = 0.41 mag, spectral type A9V) 1 is a member of the class of Double Periodic Variables, Algol-related binaries showing a long photometric cycle lasting about 33 times the orbital period with a period ratio mostly between 25 and 45 (Mennickent et al 2003, Mennickent et al 2008, Poleski et al 2010, Mennickent et al 2012a, 2012b, Mennickent 2013, Garrido et al 2013, Barría et al 2013, 2014, Pawlak et al 2013. Recently, Mennickent et al (2016) showed that DPVs are those semi-detached Algols with Btype primaries of radius slightly larger than the critical radius 2 and also that they host stable accretion discs (Mennickent, Otero, & Kołaczkowski 2016).…”

Accretion disks in Algols: Progenitors and evolution

“…Mennickent (2014) proposes a (4 M + 3.6 M , P = 3 d) progenitor for AU Mon with a 1.533 M donor and a 6.067 M gainer at present. Since we model AU Mon towards a 1.2 M donor and a 7 M gainer our progenitors with initial mass ratio (4/3.6) need to have an initial orbital period a little below 1.4 d, determined from expression (12).…”