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Ultra-Luminous Red Novae: Extreme CVs or Mergebursts?

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. Overview. A New Astrophysical Phenomenon?

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Ultra-Luminous Red Novae: Extreme CVs or Mergebursts?

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  1. 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 M. Shara, March 19, 2009

  2. Overview 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

  3. 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 M. Shara, March 19, 2009

  4. M31-RV (Red Variable) of 1988 Mbol ~ -9.5 to -9.9 = 4-7 x 105 Lsun M. Shara, March 19, 2009

  5. M31 RV was RED M. Shara, March 19, 2009

  6. V838 Mon light-echo => 6 kpc distance=> Lmax ~ 5x105 Lsun GAP M. Shara, March 19, 2009

  7. V838 Mon is VERY Red and Oxygen-Rich M. Shara, March 19, 2009

  8. CLAIMS:1) CLASSICAL NOVAE AREN’T RED2) CNe show coronal emission i.e. CNe CAN’T EJECT 10-3 Msun ENVELOPES3)Classical novae can’t reach M= -104) 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 youngRESPONSES:1+2)MWD = 0.5 Msun, mdot= few x 10-11 Msun/yr => 2x10-3 Msun ENVELOPE which becomes HUGE, COOL, RED3) Nova models making M = -9 is easy. A cold envelope with low opacity (kappa <0.4) easily gives M= -134) Nova models mimic V838 Mon and M31 RVwith multiple peaks5) V838 Mon not associated with the line-of-sight B3 starOCCUM’s RAZOR : Red Novae are TNR-powered Classical novae M. Shara, March 19, 2009

  9. A Poorly Explored Corner of Classical Nova Phase Space:WD =0.5 Msun , mdot = 7x10-11 Msun/yr,Twd = 2x106 oK=> Very slow, very red, very luminous novaMenvelope (ejected by TNR) = 1.4x10-3 Msun Envelope Expansion 1 Year! 6 nuclear flashes M. Shara, March 19, 2009

  10. Model’s Light Curve and TemperatureMatch Key Observables Lmax> 3x105 Lsun Pre-Max Rise 3-4 luminosity peaks ------------- COLD; <2,000oK M. Shara, March 19, 2009

  11. 16O : 14N : 12C Model 5.7 : 4.7 : 1.0 OXYGEN RICHSolar 2.1 : 0.25 : 1.0 M. Shara, March 19, 2009

  12. A !TESTABLE! PREDICTION for the next Ultra-Luminous Red Nova 1 Year Plateau at L=1000 Lsun… No data for V838 Or M31 RV M. Shara, March 19, 2009

  13. The Field of M31-RV in M31(F435W) M. Shara, March 19, 2009

  14. HST F300W - Candidate candidate M. Shara, March 19, 2009

  15. UV-bright candidate in 1994 Gone in 2008! (>8x fainter) m(300)=21.4 m(300)>23.7 M. Shara, March 19, 2009

  16. Fading in 5 years in F435W (60% fainter) m(435)=24.6 m(435)=24.1 M. Shara, March 19, 2009

  17. Constant in F555W over 9 years m(555)=23.5 m(555)=23.7 M. Shara, March 19, 2009

  18. Constant in F814W over 9 yearsV-I = 0.3 m(814)=23.2 m(814)=23.3 M. Shara, March 19, 2009

  19. V838 Mon and Comparison Star with HST/ACS v838 0.1” v838 comp comp M. Shara, March 19, 2009

  20. [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

  21. 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 ==> 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 M. Shara, March 19, 2009

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