Ultra-Luminous Red Novae:

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Ultra-Luminous Red Novae Extreme CVs or
Mergebursts?

• M. Shara and D. Zurek
• American Museum of Natural History
• Ofer Yaron
• Dina Prialnik
• Attay Kovetz
• Tel-Aviv University
• Howard Bond (under protest)
• Space Telescope Science Institute

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Overview
A New Astrophysical Phenomenon? M31-RV (Red
Variable) V838 Mon Why these cant be
classical novae New Nova models which mimic
Red novaeprediction Probable recovery of
M31-RV Is V838 Mon really in a
cluster? gtOccum is as sharp as ever
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The Current Party line Luminous Red Novae are A
New Astrophysical Phenomenon
M31-Red Var, V4332 Sgr and V838 Mon could be all
manifestations of a new class of astronomical
objects "Based on such comparisons, there is a
fair possibility that all three objects belong to
a new class of astronomical objects In our
opinion V838 Mon and V4332 Sgr are manifestations
of a new class of eruptive variables Our main
goal is to point out that the energy source of
the outburst of V838 Mon was, and still is, an
accretion event, i.e., gravitational energy,
rather than thermonuclear runaway The spectral
evolution and mainly the absence of any nebular
phase excludes the simplest scenario of classical
nova V838 Mon's rapid transformation from a
faint G or F star to a bright "later-than-M-class"
star in a few months may represent a previously
unobserved stage in stellar evolution, or perhaps
a new kind of star altogether
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M31-RV (Red Variable) of 1988 Mbol -9.5 to
-9.9 4-7 x 105 Lsun
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M31 RV was RED
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V838 Mon light-echo gt 6 kpc distancegt Lmax
5x105 Lsun
GAP
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V838 Mon is VERY Red and Oxygen-Rich
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CLAIMS1) CLASSICAL NOVAE ARENT RED2) CNe show
coronal emission i.e. CNe CANT EJECT 10-3 Msun
ENVELOPES 3)Classical novae cant reach M
-104) Classical novae dont show 3 or 4 peaks in
brightness5) V838 Mon is in a cluster with 4 B
starsit must be very youngRESPONSES12)MWD
0.5 Msun, mdot few x 10-11 Msun/yr gt 2x10-3
Msun ENVELOPE which becomes HUGE, COOL, RED3)
Nova models making M -9 is easy. A cold
envelope with low opacity (kappa lt0.4) easily
gives M -134) Nova models mimic V838 Mon and
M31 RVwith multiple peaks5) V838 Mon not
associated with the line-of-sight B3
starOCCUMs RAZOR Red Novae are TNR-powered
Classical novae
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A Poorly Explored Corner of Classical Nova Phase
SpaceWD 0.5 Msun , mdot 7x10-11 Msun/yr,Twd
2x106 oKgt Very slow, very red, very luminous
novaMenvelope (ejected by TNR) 1.4x10-3 Msun
Envelope Expansion 1 Year!
6 nuclear flashes
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Models Light Curve and TemperatureMatch Key
Observables
Lmaxgt 3x105 Lsun
Pre-Max Rise
3-4 luminosity peaks
-------------
COLD lt2,000oK
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16O 14N 12C Model 5.7
4.7 1.0 OXYGEN RICHSolar 2.1 0.25
1.0
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A !TESTABLE! PREDICTION for the next
Ultra-Luminous Red Nova
1 Year Plateau at L1000 Lsun No data for
V838 Or M31 RV
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The Field of M31-RV in M31(F435W)
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HST F300W - Candidate
candidate
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UV-bright candidate in 1994 Gone in 2008! (gt8x
fainter)
m(300)21.4
m(300)gt23.7
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Fading in 5 years in F435W (60 fainter)
m(435)24.6
m(435)24.1
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Constant in F555W over 9 years
m(555)23.5
m(555)23.7
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Constant in F814W over 9 yearsV-I 0.3
m(814)23.2
m(814)23.3
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V838 Mon and Comparison Star with HST/ACS
v838
0.1
v838
comp
comp
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FeII in v838 spectrum-Kaminski poster
Claim Its photoionization due to the B3V
companion Counterclaim Successive shell
ejection at slightly different velocitiesgt
collisions and weak shocks
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Summary

• Very low WD mass Very cold WD Very low
  accretion rate
• TNR in Massive WD envelopes (10-3 Msun), low
  ejection velocities, multiple light peaks and
  shells, oxygen-rich, weak shocks and gt
  Lmax106 Lsun

Good match to v838 Monhot remnant SOON! HST-
Recovered remnant at site of M31-RV is fading
like a nova, NOT like a mergeburst
TESTABLE PREDICTION for future Red Novae There
is a rise to L1000 Lsun for 1 year before
main eruption to L 106 Lsun