M. Shara, March 19, 2009

Ultra-Luminous Red Novae:Ultra-Luminous Red Novae:Extreme CVs or Mergebursts?Extreme CVs or Mergebursts?M. Shara and D. Zurek American Museum of Natural History

Ofer YaronDina PrialnikAttay Kovetz Tel-Aviv University Howard Bond (under protest)Space Telescope Science Institute

M. Shara, March 19, 2009

OverviewOverview

A New Astrophysical Phenomenon?*M31-RV (Red Variable)*V838 Mon*Why these “can’t” be classical novae… New Nova models which mimic Red novae…prediction*Probable recovery of M31-RV*Is V838 Mon really in a cluster?

==>Occum is as sharp as ever

M. Shara, March 19, 2009

The Current Party line: “Luminous Red Novae The Current Party line: “Luminous Red Novae are A New Astrophysical Phenomenon”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

M. Shara, March 19, 2009

M31-RV (Red Variable) of 1988 M31-RV (Red Variable) of 1988 Mbol ~ -9.5 to -9.9 = 4-7 x 10Mbol ~ -9.5 to -9.9 = 4-7 x 1055 Lsun Lsun

M. Shara, March 19, 2009

M31 RV wasRED

M. Shara, March 19, 2009

V838 Mon light-echo => 6 kpc V838 Mon light-echo => 6 kpc distancedistance=> Lmax ~ 5x10=> Lmax ~ 5x1055 Lsun Lsun

GAP

M. Shara, March 19, 2009

V838 Mon is V838 Mon is VERY RedVERY Red and and Oxygen-RichOxygen-Rich

M. Shara, March 19, 2009

CLAIMS:CLAIMS:1) CLASSICAL NOVAE AREN’T RED1) CLASSICAL NOVAE AREN’T RED2) CNe show coronal emission 2) CNe show coronal emission

i.e. CNe CAN’T EJECT 10i.e. CNe CAN’T EJECT 10-3-3 Msun ENVELOPES Msun ENVELOPES 3)Classical novae can’t reach M= -103)Classical novae can’t reach M= -104) Classical novae don’t show 3 or 4 peaks in brightness4) Classical novae don’t show 3 or 4 peaks in brightness5) V838 Mon is in a “cluster” with 4 B stars…it must be very young5) V838 Mon is in a “cluster” with 4 B stars…it must be very young

RESPONSES:RESPONSES:1+2)M1+2)MWDWD = 0.5 Msun, mdot= few x 10 = 0.5 Msun, mdot= few x 10-11-11 Msun/yr => 2x10 Msun/yr => 2x10-3-3 Msun Msun ENVELOPE which becomes HUGE, COOL, REDENVELOPE which becomes HUGE, COOL, RED3) Nova models making M = -9 is easy. A cold envelope 3) Nova models making M = -9 is easy. A cold envelope with low opacity (kappa <0.4) easily gives M= -13with low opacity (kappa <0.4) easily gives M= -134) Nova models mimic V838 Mon and M31 RV4) Nova models mimic V838 Mon and M31 RVwith multiple peakswith multiple peaks5) V838 Mon not associated with the line-of-sight B3 star5) V838 Mon not associated with the line-of-sight B3 star

OCCUM’s RAZOR : Red Novae are TNR-powered Classical novaeOCCUM’s RAZOR : Red Novae are TNR-powered Classical novae

M. Shara, March 19, 2009

A Poorly Explored Corner of Classical Nova Phase Space:A Poorly Explored Corner of Classical Nova Phase Space:WD =0.5 Msun , mdot = 7x10WD =0.5 Msun , mdot = 7x10-11-11 Msun/yr,Twd = 2x10 Msun/yr,Twd = 2x106 o6 oKK=> Very slow, very red, very luminous nova=> Very slow, very red, very luminous novaMenvelope (ejected by TNR) = 1.4x10Menvelope (ejected by TNR) = 1.4x10-3-3 Msun Msun

6 nuclear flashes Envelope Envelope Expansion Expansion 1 Year!1 Year!

M. Shara, March 19, 2009

Model’s Light Curve and TemperatureModel’s Light Curve and TemperatureMatch Key ObservablesMatch Key Observables

-------------COLD;<2,000oK

Lmax> 3x105 LsunPre-Max Rise

3-4 luminosity peaks

M. Shara, March 19, 2009

1616O : O : 1414N : N : 1212C C Model 5.7 : 4.7 : 1.0 Model 5.7 : 4.7 : 1.0 OXYGEN RICHOXYGEN RICH

Solar 2.1 : 0.25 : 1.0Solar 2.1 : 0.25 : 1.0

M. Shara, March 19, 2009

A A !TESTABLE!!TESTABLE! PREDICTION for PREDICTION for the next Ultra-Luminous Red Novathe next Ultra-Luminous Red Nova

1 Year Plateau at L=1000 Lsun…No data for V838Or M31 RV

M. Shara, March 19, 2009

The Field of M31-RV in M31(F435W)The Field of M31-RV in M31(F435W)

M. Shara, March 19, 2009

HST F300W - CandidateHST F300W - Candidate

candidate

M. Shara, March 19, 2009

UV-bright candidate in 1994 UV-bright candidate in 1994 Gone in 2008! (>8x fainter)Gone in 2008! (>8x fainter)

m(300)=21.4 m(300)>23.7

M. Shara, March 19, 2009

Fading in 5 years in F435W (60% fainter)Fading in 5 years in F435W (60% fainter)

m(435)=24.1 m(435)=24.6

M. Shara, March 19, 2009

Constant in F555W over 9 yearsConstant in F555W over 9 years

m(555)=23.7 m(555)=23.5

M. Shara, March 19, 2009

Constant in F814W over 9 yearsConstant in F814W over 9 yearsV-I = 0.3V-I = 0.3

m(814)=23.3 m(814)=23.2

M. Shara, March 19, 2009

V838 Mon and Comparison Star with HST/ACSV838 Mon and Comparison Star with HST/ACS

v838 v838

comp comp

0.1”

M. Shara, March 19, 2009

[FeII] in v838 spectrum-Kaminski poster[FeII] in v838 spectrum-Kaminski poster

Claim: It’s photoionization due to the B3V companion

Counterclaim: Successive shell ejection at slightly different velocities=> collisions and weak shocks

M. Shara, March 19, 2009

SummarySummary*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 ==> Lmax~106 Lsun *Good match to v838 Mon…hot 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 L~1000 Lsun for ~1 year before “main eruption” to L ~ 106 Lsun