史上最大規模の矮新星アウトバースト
MASTER OT J030227.28+191754.5(2105-T-08 [PI 反保]:
特異な突発天体MASTER OT J030227.28+191754.5のフォローアップ観測)

Y. Tampo (Kyoto U. D2)
K. Isogai, N. Kojiguchi,
T. Kato, D. Nogami(Kyoto U.),VSNET collabolation
OISTER collabolation
Tomo-e collabolation
OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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MASTER OT J030227.28+191754.5
Intro.

Lightcurve

A possible optical counterpart of IceCube neutrino event?
Isogai, YT+: double-peaked emission → disk-powered & dwarf nova!
Atel #15074(not likely a REAL counterpart tho)Spectra60 d duration & 10.2 mag amplitude : Largest valules in dwarf novae⇒ How its uniqueness can be understood?

Discus.

SummaryYT+20b
editedOISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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Dwarf novae & thermal instability
Intro.

Lightcurve

SpectraPrimary white dwarf + low-mass star + accretion disk
→ orbital period: 80min - 10 hr→ mass ratio: 0.03 - 1.0 (MSec/MWD)
Reccurent outbursts by thermal instability→ viscosity jump b/w hot-ionized & cool-neutral states

Osaki 1974
Meyer+1981

a fewdays
Data fromKepler
Discus.

2-5 mag

Summary

OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

3WZ Sge stars & tidal instability
Intro.

Lowest mass ratio (<0.1) & shortest orbital period (〜80min)
Light
curve

Whitehurst 1981
Osaki+2002
Kato 2015

Resonance b/w Kepler disk & secondary ⇒ strong tidal dissipation→ energetic “superoutburst” & short-period “superhump”→ deformation of accretion disk: spiral arm (2:1) & eccentric (3:1)

SpectraData from VSNET
Discus.

Summary

early superhump

ordinary superhump

OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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MASTER OT J030227.28+191754.5 Observation summary
Intro.

Lightcurve

SpectraDiscus.

Telescopes

Wavelength

Mode

Pupose

VSNET
incl. Kyoto Okujo

OpticalTime-resolved
photometry

early & ordinary superhump
periodOISTER
MITSuME (x3)
SaCRA
KanataNayutaOptical〜IRMulti-color
photometrycolor evolution, SED analysis,
early superhump mapping

Seimei / KOOLS

VPH-blue
VPH683/495

R〜500
R〜2000Line species / profile evolution
Doppler tomography

Tomo-eOptical (clear)

2 Hz snap+ time-resolve

Outburst profile
Short-time variability

NICER

X-ray

Summary

SED, short-time variability
To be analyzed by Kimura-sanOISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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Light curve & superhumps
Intro.

Lightcurve

SpectraDiscus.

MASTER OT J030227.28+191754.5: 10.2 mag amplitude & 60-d duration !
→ largest in DNe⇒ how its uniqueness can be understood?

early SH: 0.05986 dordinary SH: 0.06131 d

Early & ordinary superhumps→ WZ Sge star
No historical record of oubutrsts→ outburst cycle > 10 yrs

SummaryOISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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Multi-color observations
Intro.

Optical-IR LCs follow V-bandLightcurveSpectra

Color temperature: outer disk emission→ 13000 K around peak
→ 10000 K in later phase of outburst→ 6000 K after rapid decline: consistent w/ other DNe e.g., Shugarov+2022

RedderDiscus.

Summary

OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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Early superhump mapping

MASTER J0302

Intro.

Lightcurve

Non axisymmetric accretion disk
: orbital rotation + self-occultation
Early SH profile⇒ disk-height structure
Uemura+2012

Spectra

MITSuME & MuSaSHI
Discus.

SummaryPNVJ0044; YT+22b

V455 And; Uemura+2012

OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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MASTER J0302 among WZ Sge stars
Intro.

Lightcurve

SpectraOrbital period & mass ratio from superhump: typical as WZ Sge stars: standard evolution?
From X-rays, host an ONe & 1.3 Msun WD?
⇐⇒ usually 0.8 Msun WD: evolution channel isan open question

Discus.

Summary— theoretical evolution path: Knigge+2011
Pala+21
OISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

9MASTER J0302 as an unprecedented DN
Intro.

Lightcurve

SpectraDiscus.

①Bright absolute magnitude②Long duration〜2.1 absolute mag at outburst peak⇐⇒ 3-6 mag

60-d duration in MASTER J0302⇐⇒ 20-30 d

Only -0.35 mag by 0.8→1.3 Msun WD

Duration 〜 accreted mass in outburst

Warner 1987

1020 g/s accretion rate from α disk
⇒ x100 of typical WZ Sge stars!

disk mass

viscosity

WD mass

Coppejans+16
SummaryYT+20b
editedOISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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MASTER J0302: the most energetic dwarf nova outburst everIntro.

Lightcurve●Large amplitude of >10 mag and long duration of 60 d.
⇒ largest values in dwarf nova outbursts●

Early+ordinary superhumps & double-peaked lines detected⇒ confirmed as a WZ Sge-type dwarf nova

●Orbital period & mass ratio in normal range of WZ Sge-type dwarf novae⇐ BUT can harbor a ONe massive WD in system?

●

Its peculiarity (amplitude, duration, wind feature) can be explained
as a WZ Sge-type dwarf nova in extreme conditions

SpectraDiscus.

SummaryOISTER WS 2023, MASTER OT J030227.28+191754.5 outburst, @Nagoya U., Y. Tampo@Kyoto U.

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