C.D.S. - SIMBAD4 rel 1.7 - 2019.10.18CEST15:16:01

2000ApJ...528L..97H - Astrophys. J., 528, L97-L100 (2000/January-2)

A theoretical light-curve model for the 1999 outburst of U Scorpii.


Abstract (from CDS):

A theoretical light curve for the 1999 outburst of U Scorpii is presented in order to obtain various physical parameters of the recurrent nova. Our U Sco model consists of a very massive white dwarf (WD) with an accretion disk and a lobe-filling, slightly evolved, main-sequence star (MS). The model includes a reflection effect by the companion and the accretion disk together with a shadowing effect on the companion by the accretion disk. The early visual light curve (with a linear phase of t∼1-15 days after maximum) is well reproduced by a thermonuclear runaway model on a very massive WD close to the Chandrasekhar limit (MWD=1.37±0.01 M), in which optically thick winds blowing from the WD play a key role in determining the nova duration. The ensuing plateau phase (t∼15-30 days) is also reproduced by the combination of a slightly irradiated MS and a fully irradiated flaring-up disk with a radius ∼1.4 times the Roche lobe size. The cooling phase (t∼30-40 days) is consistent with a low-hydrogen content of X~0.05 of the envelope for the 1.37 M WD. The best-fit parameters are the WD mass of MWD∼1.37 M, the companion mass of MMS∼1.5 M (0.8-2.0 M is acceptable), the inclination angle of the orbit (i∼80°), and the flaring-up edge, the vertical height of which is ∼0.30 times the accretion disk radius. The duration of the strong wind phase (t∼0-17 days) is very consistent with the BeppoSAX supersoft X-ray detection at t∼19-20 days because supersoft X-rays are self-absorbed by the massive wind. The envelope mass at the peak is estimated to be ∼3x10–6 M, which is indicates an average mass accretion rate of ∼2.5x10–7 M.yr–1 during the quiescent phase between 1987 and 1999. These quantities are exactly the same as those predicted in a new progenitor model of Type Ia supernovae.

Abstract Copyright:

Journal keyword(s): Accretion, Accretion Disks - Stars: Binaries: Close - Stars: Novae, Cataclysmic Variables - Stars: Individual: Constellation Name: U Scorpii

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
1 V* T CrB Sy* 15 59 30.1619486506 +25 55 12.607985109 2.69 2.10 2.00     M3III+p 637 0
2 NOVA Sco 1863 No* 16 22 30.7782086963 -17 52 43.162570042   8.80 8.70     F8+K2 458 0

    Equat.    Gal    SGal    Ecl

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