Abstract
Atheoreticallightcurveforthe1999outburstofUScorpiiispresentedinordertoobtai nvariousphysicalparametersoftherecurrentnova. OurUScomodelconsistsofaverymassivewhitedwarf(WD)withanaccretiondiskandalobe- filling,slightlyevolved,main-sequencestar(MS). Themodelincludesareflectioneffectbythecompanionandtheaccretiondisktogetherwithas hadowingeffectonthecompanionbytheaccretiondisk. Theearlyvisuallightcurve(withalinearphaseoft∼1-15daysaftermaximum) iswellreproducedbyathermonuclearrunawaymodelonaverymassiveWDclosetotheChandrasek harlimit(M WD=1.37±0.01M⊙), inwhichopticallythickwindsblowingfromtheWDplayakeyroleindeterminingthenovadurati on.Theensuingplateauphase(t∼15-30days) isalsoreproducedbythecombinationofaslightlyirradiatedMSandafullyirradiatedflarin g-updiskwitharadius∼1.4timestheRochelobesize.Thecoolingphase(t∼30- 40days)isconsistentwithalow-hydrogencontentofX≈0.05oftheenvelopeforthe1. 37M⊙WD.Thebest-fitparametersaretheWDmassofM WD∼1.37M⊙,thecompanionmassofM MS∼1.5M⊙(0.8-2.0M⊙isacceptable), theinclinationangleoftheorbit(i∼80°),andtheflaring-upedge, theverticalheightofwhichis∼0.30timestheaccretiondiskradius. Thedurationofthestrongwindphase(t∼0-17days) isveryconsistentwiththeBeppoSAXsupersoftX-raydetectionatt∼19- 20daysbecausesupersoftX-raysareself-absorbedbythemassivewind. Theenvelopemassatthepeakisestimatedtobe∼3×10 -6M⊙,whichisindicatesanaveragemassaccretionrateof∼2. 5×10-7M⊙yr -1duringthequiescentphasebetween1987and1999. ThesequantitiesareexactlythesameasthosepredictedinanewprogenitormodelofTypeIasup ernovae.
Original language | English |
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Pages (from-to) | L97-L100 |
Journal | Astrophysical Journal |
Volume | 528 |
Issue number | 2 PART 2 |
DOIs | |
Publication status | Published - 2000 Jan 10 |
Keywords
- Accretion, accretion disks
- Binaries: close
- Novae, cataclysmic variables
- Stars: individual (U Scorpii)
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science