Luminous red nova

V838 Monocerotis – a possible Luminous red nova

A luminous red nova (abbr. LRN, pl. luminous red novae, pl.abbr. LRNe) is a stellar explosion thought to be caused by the merging of two stars. They are characterised by a distinct red colour, and a light curve that lingers with resurgent brightness in the infrared. Luminous red novae are not to be confused with standard novae, explosions that occur on the surface of white dwarf stars.

Discovery

A small number of objects exhibiting the characteristics of luminous red novae have been observed over the last 30 years or so. The red star M31 RV in the Andromeda Galaxy flared brightly during 1988 and may have been a luminous red nova. In 1994, V4332 Sgr, a star in the Milky Way galaxy, flared similarly, and in 2002, V838 Mon followed suit and was studied quite closely.

The first confirmed Luminous Red Nova was the object M85 OT2006-1, in the Messier 85 galaxy. It was first observed during the Lick Observatory Supernova Search, and subsequently investigated by a team of astronomers from both U.C. Berkeley and Caltech. The team, led by Shrinivas Kulkarni confirmed its difference from known explosions such as novae and thermal pulses, and announced Luminous Red Novae as a new class of stellar explosion in a press release on May 23, 2007 and by publication in the journal Nature.

V1309 Scorpii is a luminous red nova that followed the merger of a contact binary in 2008.^[1]

In January 2015, a luminous red nova was observed in the Andromeda Galaxy.^[2]

On February 10, 2015, a luminous red nova was observed in the Pinwheel Galaxy by Dumitru Ciprian Vîntdevară from Planetarium and Astronomical Observatory of the Museum Vasile Parvan in Barlad, Romania.^[3]^[4]

Characteristics

A luminous red nova has the following observed characteristics:

The luminosity of the explosion is between that of a supernova (which is brighter) and a nova (dimmer).
The visible light lasts for weeks or months, and is distinctively red in colour, becoming dimmer and redder over time. As the visible light dims, the infrared light grows and also lasts for an extended period of time, usually dimming and brightening a number of times.
Infrared observations of M85 OT2006-1 have shown it to be quite cool for a star (slightly less than 1000 K). This may, or may not, be a characteristic shared by other luminous red novae.

Evolution

The team investigating M85 OT2006-1 believe it to have formed when two main sequence stars merged. (See the article on V838 Mon for further information on mergebursts and alternative possibilities.)

At the time the mergeburst occurs, the LRN appears to expand extremely rapidly, reaching thousands to tens of thousands of solar radii in only a few months. This would cause the object to cool, explaining the intriguing co-existence of a bright flash with a cool post-flash object.

Other viewpoints

Some astronomers believe it to be premature to declare a new class of stellar explosions based on such a limited number of observations. For instance, Pastorello et al. 2007^[5] explained that the event may be due to a type II-p supernova and Todd et al. 2008^[6] pointed out that supernovae undergoing a high level of extinction will naturally be both red and of low luminosity.

References

↑ Tylenda, R.; Hajduk, M.; Kamiński, T.; Udalski, A.; Soszyński, I.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Poleski, R.; Wyrzykowski, Ł.; Ulaczyk, K. (2011). "V1309 Scorpii: Merger of a contact binary". Astronomy & Astrophysics. 528: 114. arXiv:1012.0163v2. Bibcode:2011A&A...528A.114T. doi:10.1051/0004-6361/201016221.
↑ "M31N 2015-01a - A Luminous Red Nova". The Astronomer's Telegram. Retrieved 2015-03-18.
↑ "PSN J14021678+5426205 in M 101". The Astronomer's Telegram.
↑ "http://www.rochesterastronomy.org/". Bright Supernova. External link in |title= (help)
↑ Pastorello, A.; Della Valle, M.; Smartt, S. J.; Zampieri, L.; Benetti, S.; Cappellaro, E.; Mazzali, P. A.; Patat, F.; Spiro, S.; Turatto, M.; Valenti, S. (2007). "A very faint core-collapse supernova in M85". Nature. 449 (7164): 1. arXiv:0710.3753. Bibcode:2007Natur.449E...1P. doi:10.1038/nature06282.
↑ Thompson, Todd A.; Prieto, José L.; Stanek, K. Z.; Kistler, Matthew D.; Beacom, John F.; Kochanek, Christopher S. (2009). "A New Class of Luminous Transients and a First Census of their Massive Stellar Progenitors". The Astrophysical Journal. 705 (2): 1364. arXiv:0809.0510. Bibcode:2009ApJ...705.1364T. doi:10.1088/0004-637X/705/2/1364.

External links

Star

Evolution	Formation Pre-main-sequence star Main sequence Red giant branch Horizontal branch Asymptotic giant branch Dredge-up Instability strip Red clump PG1159 star Mira variable Planetary nebula Protoplanetary nebula Luminous red nova Luminous blue variable Wolf–Rayet star Stellar population Supernova Supernova impostor Hypernova Hertzsprung–Russell diagram Color–color diagram

Protostars	Molecular cloud H II region Bok globule Young stellar object Herbig–Haro object Hayashi track Henyey track Orion T Tauri FU Orionis Herbig Ae/Be

Luminosity class	Subdwarf Dwarf Blue Red White Yellow Black Brown Subgiant Giant Blue Red Bright giant Supergiant Blue Red Yellow Hypergiant Yellow Blue straggler Variable star

Spectral classification	O B A F G K M Be OB Subdwarf O Subdwarf B Late-type Chemically peculiar Am Ap/Bp Oscillating Barium Carbon CH CN Extreme helium Lambda Boötis Lead Mercury-manganese S Shell Technetium

Remnants	White dwarf Black dwarf Helium planet Neutron star Pulsar Binary X-ray X-ray binary X-ray burster Magnetar Stellar black hole Compact star Quark Strange Preon Planck Exotic Stellar core: EF Eridani B

Theoretical stars	Dark-matter star Dark-energy star Black star Gravastar Frozen star Q star Quasi-star Thorne–Żytkow object Iron star Blitzar

Nucleosynthesis	Deuterium burning Lithium burning Proton–proton chain CNO cycle Helium flash Triple-alpha process Carbon burning Neon burning Oxygen burning Alpha process Silicon burning S-process R-process Fusor Nova Remnants

Structure	Core Convection zone Microturbulence Oscillations Radiation zone Atmosphere Photosphere Starspot Chromosphere Corona Stellar wind Bubble Asteroseismology Eddington luminosity Kelvin–Helmholtz mechanism

Properties	Designation Dynamics Effective temperature Kinematics Magnetic field Magnitude Absolute Mass Metallicity Rotation UBV color Variability

Star systems	Binary Contact Common envelope Multiple Accretion disk Star cluster Open cluster Globular cluster Super star cluster Planetary system Earth's Solar System

Earth-centric observation of	Pole star Circumpolar star Magnitude Apparent Extinction Photographic Color Radial velocity Proper motion Parallax Photometric-standard star

Lists	Star names Arabic Chinese Extremes Most massive Highest temperature Largest volume Smallest volume Brightest Historical Most luminous Nearest Nearest bright Stars with exoplanets Brown dwarfs White dwarfs Milky Way novae Notable supernovae Supernova candidates Supernova remnants Planetary nebulae Timeline of stellar astronomy

Related articles	Substellar object Brown dwarf Sub-brown dwarf Planet Galactic year Galaxy Supercluster Helioseismology Guest star Constellation Asterism Gravity Intergalactic star Infrared dark cloud Starfield

Category:Stars · Star portal

This article is issued from Wikipedia - version of the 10/30/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.