Multiwavelength modeling the SED of supersoft X-ray sources. II. RS Ophiuchi: From the explosion to the SSS phase

Abstract

Physical parameters of the nova RS Oph were determined from its X-ray/IR spectrum. -The model revealed the presence of a strong stellar and nebular component. -The luminosity was super-Eddington during the whole burning phase. -The high luminosity was sustained by a super-critical accretion.Abstract RS Oph is a recurrent symbiotic nova that undergoes nova-like outbursts on a time scale of 20 years. Its two last eruptions (1985 and 2006) were subject of intensive multiwavelengths observational campaign from the X-rays to the radio. This contribution aims to determine physical parameters and the ionization structure of the nova from its explosion to the first emergence of the supersoft X-rays (day 26) by using the method of multiwavelength modelling the SED. From the very beginning of the eruption, the model SED revealed the presence of both a strong stellar and nebular component of radiation in the spectrum. During the first 4 days, the nova evinced a biconical ionization structure. The ∼ 8200 K warm and 160-200 R⊙ extended pseudophotosphere encompassed the white dwarf (WD) around its equator to the latitude > 40 • . The remaining space around the WD's poles was ionized, producing a strong nebular continuum with the emission measure EM ∼ 2.3 × 10 62 cm −3 via the fast wind from the WD. The luminosity of the burning WD was highly super-Eddington for the whole investigated period. The wind mass loss at rates of 10 −4 − 10 −5 M⊙ yr −1 and the presence of jets suggest an accretion throughout a disk at a high rate, which can help to sustain the super-Eddington luminosity of the accretor for a long time.

The recurrent nova RS Oph: simultaneous B- and V- band observationsof the flickering variability

“…Mondal et al (2018) from the absorption band indices derived the spectral type to be M2-M3. Skopal (2015a) found that the radiation from the giant corresponds to its effective temperature T ef f = 3800 − 4000 K, and the radius Rg = (61 − 55)(d/1.6 kpc) R⊙. Comparing our spectra with spectra of red giants (Houdashelt et al 2000;Bagnulo et al 2003;Zhong et al 2015), we estimate a similar spectral type M2 III.…”

Proton acceleration in thermonuclear nova explosions revealed by gamma rays

“…7). The photosphere fit of 2006 eruption [66], when rescaled to the nova distance of 2.45 kpc, provides a similar radius (245 − 310) R , and temperature (8200 K).…”

“…Filled markers show the flux after subtraction of Hα and Hβ line contributions. The thick black lines show a black-body emission used in the modeling, while the dashed line shows for comparison the average 2006 spectral fit from[66] (with the photosphere radius corrected to the distance of 2.45 kpc).…”

Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration against Spectral Types and V − K Color

“…Completeness. A cursory examination of the Two Micron All Sky Survey (2MASS) and Skiff catalogs (Cutri et al 2003a;Skiff 2014) can give an indication of the completeness of our giant star sample. First, the 2MASS catalog was sampled for all objects brighter than K < 3.5, resulting in approximately 13,000 objects.…”

“…Calibration of "canonical" values for temperature and radius has wide-ranging utility in astrophysics. Evaluation of X-ray transient host stars (Skopal 2015;McCollum et al 2018), interpretation of protoplanetary environments (Arulanantham et al 2017), establishing the temperature of a galactic runaway giant (Massey et al 2018), and modeling of galactic longperiod variables (Barthès & Luri 2001) are a few examples of the use of our earlier calibration of effective temperature (van Belle et al 1999, hereafter vB99). Improved temperature calibrations can have wide-ranging effects, particularly when they refine calibrations used in large surveys (e.g., the symbiotic star survey of Akras et al 2019).…”