????? 2002 - I

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The nature of peculiar red novae with K-M spectra
in the outbursts
Stars that Erupt into Cool Supergiants (SECS)
(Munari et al, 2002)
Vitaly Goranskij, SAI, Moscow University in
cooperation with Natalia Metlova, SAI Crimean
Station, Ukraine Sergei Shugarov, SAI, Moscow
University Astronomical Institute
of Slovak Academy of Sciences Peter Kroll,
Sonneberg Observatory, Germany Elena Barsukova,
Valentina Klochkova Azamat Valeev,
Special Astrophysical Observatory of
Russian Academy of Sciences.


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What is a red nova?
Wide system containing a B type star. Explosion
of the hot companion up to MV
10m. Cool K0 M giant in outburst. Mass
equal to a few solar masses erupted into
space. Very cool oxygen-rich stellar remnant,
supergiant of L M type. Not a classical
nova, a sample of a new class of
astrophysical objects.
A term of nova means only a new star
unseen earlier.
Tycho Brage observes a sudden appearance of
a nova star in 1572 (Flammarion textbook,
1902). In the Flammarions textbook all
the novae were explained as a result of
stellar collisions.
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GCVS editors did not believe that the star might
be both a nova and a red supergiant as written
in different papers and gave It two names
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L type spectrum out of the V band
Dust formation
The photometric history of V838 Mon. I. The 2002
outburst

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Spectrum of V838 Mon in the outburst (SAO RAS 1-m
Zeiss telescope)
Resembles K0I type star, but the absorption lines
are 3-4 times stronger
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Pre-maximum
Shock wave in the peak of outburst
After the peak of outburst
Spectra of V838 Mon in the different phases of
the outburst
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Classical P Cyg profiles Smooth profiles,
radially symmetric outflow
Line profiles of high-resolution spectra
V838 Mon in the peak of outburst. BTA/NES
spectra (resolution 1 km/s) first analysed
by Kipper et al. (2004)
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The photometric history of V838 Mon. II.
Pre- and post - explosion evolution
Digital reduction of Sonneberg (Germany) and
Sternberg Institute (Moscow, Russia) photographic
plates.
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V838 Mon, binary of B3V stars
Single B3V star
V838 Mon progenitor. Photography taken on 1943
February 28 with the 40-cm astrograph of
Sonneberg Observatory (Germany).
Fragment of HST image
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The photometric post-outburst history of V838
Mon . Different filters.
B3V star inside the red supergiant!
Radius of the red supergiant it equal to
30000 Rsun
Capture and engulf of its B3V companion.
Julian Date
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Spectral energy distribution V838 Mon before
the outburst (progenitor) and after outburst
(L type supergiant in 2002). Corrected for
reddening of E(B-V)0.77.
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Unreddened spectral energy distributions of
V838 Mon components.
If we know correct energy distributions of
progenitor binary and a surviving B3V
companion, we can calculate the energy
distribution of exploded star. It was a B3V
star, too.
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Cluster of B type stars around V838 Mon.
Color-Magnitude diagram
The location of V838 Mon components on the Afsar
Bonds CM diagram of the cluster. Both
components have the reddening equal to the
clusters one but are low-luminosity stars.
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Flux density
Post-outburst spectral evolution of V838 Mon
Approach engulf
Wavelength, Angstrem
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Photometric history of V4332 Sgr. I.
POSS-1 1950
The light curve in the R filter. Brightening
before outburst is seen
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SAI, 1986
Photometric history of V4332 Sgr. II.
V band light curve
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Spectral energy distributions of V4332 Sgr before
and after 1994 outburst
Reddening of E(B-V)0.32 is taken into account.
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V4332 Sgr spectrum 11 years after outburst
Slit
Flux density
Wavelength
Resonance lines of Al I, Ca I, Sr I triplets of
Mn I, Cr I intercombination line of Mg I
4571Å faint emissions of Rb I molecular
emissions of AlO, TiO, large number of Cr I lines
and wide TiO bands of M7 type star with the
temperature of 2700?. Emission line spectrum
belongs to cool gas nebula. T1100K.
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Comparison of two red novae spectra, V4332 Sgr
and V838 Mon in 2007
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V838 Mon surroundings and Light
echo
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Light echo of V838 Mon
Compared with X-ray light echo of GRB 031203
Our images taken with 1-m Zeiss telescope
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First HST image of V838 Mon light echo taken on
2002 April 30 in B band. Arcs and the central gap
are seen
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Observer
Light years
Boundary of the dense interstellar medium
Model of light echo
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Echo expansion in four directions
Superluminal part
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Different structures of nebulosity being cut by
narrow ellipsoid give the arcs
Computer modeling of surrounding dust nebula
Distance 6 kpc generally accepted
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Bad approximation of superluminal part
Distance 6 kpc
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Computer modeling of light echo. II. Distance 4
kpc.
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CONCLUSION
We assume that V838 Mon components both are young
pre main sequence stars in the stage of
gravitational contraction, and the ignition of
hydrogen in the center of one of them gave a
powerful push to star expansion. Later, when
the radiation of the internal burning and shock
waves reached the surface, its area became so
large that could not be heated up to high
temperature. This may be the case why red novae
look like cool supergiants.
Not a Thorne Zitkow like event. No place
for a neutron star in the young binary
system. Exploding star had zero age main
sequence composition (Kipper et al., 2006).
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Thank you