Nova

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Nova

A nova (pl. novae or novas) is a cataclysm

Cataclysm

The cataclysm is the Greek expression for the Deluge , from the Greek kataklysmos, to 'wash down' . Erudite Bible studies drew it into the English language in 1633 and it has also been used to describe biblical events such as the Noah's Ark, the destruction of Sodom and Gomorrah, and Plagues of Egypt#Death of Firstborn ??? ??????....
ic nuclear explosion caused by the accretion

Accretion (astrophysics)

In astrophysics, the term accretion is used for at least two distinct processes.The first and most common is the growth of a massive object by gravity attracting more matter, typically gaseous matter in an accretion disc....
of hydrogen onto the surface of a white dwarf

White dwarf

A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. Because a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth, it is very density....
star

Star

A star is a massive, luminous ball of Plasma that is held together by its own gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth....
. Novae are not to be confused with Type Ia supernova

Type Ia supernova

File:Main tycho remnant full.jpgA Type Ia supernova is a sub-category of cataclysmic variable stars that results from the violent explosion of a white dwarf star....
e, or another form of stellar explosion first announced by Caltech in May 2007, Luminous Red Nova

Luminous red nova

File:V838 Mon HST.jpgLuminous red novae are stellar explosions thought to be caused by the merger of two stars. They are characterised by a distinct red colour, and a light curve that lingers with resurgent brightness in the infrared....
e.

Occurrence rate, and astrophysical significance
Astronomers estimate that the Milky Way

Milky Way

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Occurrence rate, and astrophysical significance

Astronomers estimate that the Milky Way

Milky Way

The Milky Way, sometimes called simply the Galaxy, is the galaxy in which the Solar System is located. It is a barred spiral galaxy that is part of the Local Group of galaxies....
experiences roughly 30 to 60 novae per year, with a likely rate of about 40. The number of novae discovered in the Milky Way each year is much lower, about 10.. Roughly 25 novae brighter than about magnitude 20 are discovered in the Andromeda Galaxy

Andromeda Galaxy

The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years away in the constellation Andromeda . It is the nearest spiral galaxy to our own, the Milky Way Galaxy....
each year and smaller numbers are seen in other nearby galaxies.

Spectroscopic

Spectroscopy

Spectroscopy was originally the study of the interaction between radiation and matter as a function of wavelength . In fact, historically, spectroscopy referred to the use of visible light dispersed according to its wavelength, e.g....
observation of nova ejecta nebulae has shown that they are enriched in elements such as helium, carbon

Carbon

Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....
, nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674?. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere....
, oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
, neon

Neon

Neon is the chemical element that has the symbol Ne and atomic number 10. Although a very common element in the universe, it is rare on Earth....
, and magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....
. The contribution of novae to the interstellar medium

Interstellar medium

In astronomy, the interstellar medium is the gas and cosmic dust that pervade interstellar space: the matter that exists between the stars within a galaxy....
is not great; novae supply only 1/50th the amount of material to the Galaxy as supernovae, and only 1/200th that of red giant

Red giant

A red giant is a luminous giant star of low or intermediate mass that is in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower....
and supergiant

Supergiant

Supergiants are among the most massive stars. In the Hertzsprung-Russell diagram they occupy the top region of the diagram. In the spectral classification supergiants are class Ia or Ib ....
stars.

Recurrent novae like RS Ophiuchi (those with periods on the order of decades) are rare. Astronomers theorize however that most, if not all, novae are recurrent, albeit on time scales ranging from 1,000 to 100,000 years. The recurrence interval for a nova is less dependent on the white dwarf's accretion rate than on its mass; with their powerful gravity, massive white dwarfs require less accretion to fuel an outburst than lower-mass ones. Consequently, the interval is shorter for high-mass white dwarfs.

Historical significance

The astronomer Tycho Brahe

Tycho Brahe

Tycho Brahe, born Tyge Ottesen Brahe , was a Danish nobility known for his accurate and comprehensive astronomy observations. Coming from Sk?neland, then part of Denmark, now part of modern-day Sweden, Brahe was well known in his lifetime as an astronomy and alchemy....
observed the supernova

Supernova

A supernova is a Astronomy#Stellar astronomy explosion. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months....
SN 1572

SN 1572

SN 1572 , "B Cassiopeiae" , or 3C 10 was a supernova of Type Ia supernova in the constellation Cassiopeia , one of about eight supernovae visible to the naked eye in historical records....
in the constellation Cassiopeia

Cassiopeia (constellation)

Cassiopeia is a constellation in the northern sky. In Greek mythology it was considered to represent the vain queen Cassiopeia , who boasted about her unrivaled beauty....
, and described it in his book de stella nova (Latin

Latin

Latin is an Italic language, historically spoken in Latium and Ancient Rome. Through the Military history of the Roman Empire, Latin spread throughout the Mediterranean and a large part of Europe....
for "concerning the new star"), giving rise to the name nova. In this work he argued that a nearby object should be seen to move relative to the fixed stars, and that the nova had to be very far away. Though this was a supernova and not a classical nova, the terms were considered interchangeable until the 1930s.

Novae as distance indicators

Novae have some promise for use as standard candles. For instance, the distribution of their absolute magnitude

Absolute magnitude

In astronomy, absolute magnitude measures a celestial object's intrinsic brightness. To derive the absolute magnitude from the observed apparent magnitude of a celestial object its value is corrected for distance to the observer....
is bimodal

Bimodal distribution

In statistics, a bimodal distribution is a continuous probability distribution with two different mode s. These appear as distinct peaks in the probability density function, as shown in Figure 1....
, with a main peak at magnitude -8.8, and a lesser one at -7.5. Novae also have roughly the same absolute magnitude 15 days after their peak (-5.5). Comparisons of nova-based distance estimates to various nearby galaxies and galaxy clusters with those done with Cepheid variable stars have shown them to be of comparable accuracy.

Bright novae since 1890

Year	Nova	Maximum brightness Apparent magnitude The apparent magnitude of a celestial body is a measurement of its brightness as seen by an observer on Earth, normalized to the value it would have in the absence of the Earth's atmosphere....
1891	T Aurigae T Aurigae T Aurigae was a nova, which lit up in the constellation Auriga in 1892. It reached a brightness of 3.8 Apparent magnitude and decreased within 100 days by around 3 mag....	+3.8
1898	V1059 Sagittarii V1059 Sagittarii V1059 Sagittarii was a nova, which lit up in 1898 in the constellation Sagittarius . V1059 Sagittarii reached apparent magnitude 4.5....	+4.5
1899	V606 Aquilae V606 Aquilae V606 Aquilae was a nova, which lit up in the constellation Aquila in 1899. It reached 5.5 Apparent magnitude.External links ****...	+5.5
1901	GK Persei GK Persei GK Persei was a bright nova occurring in 1901 1500 light-years away in Perseus , with right ascension and declination . It reached a maximum apparent magnitude of 0.2, the brightest nova of modern times until V603 Aquilae....	+0.2
1903	DM Geminorum DM Geminorum DM Geminorum or Nova Geminorum 1903 was a nova which appeared in 1903 in the constellation Gemini and reached a brightness of 4.8 apparent magnitude....	+4.8
1905	V604 Aquilae V604 Aquilae V604 Aquilae or Nova Aquilae 1905 was a nova, which occurred in the constellation Aquila in 1905 with a maximum brightness of 7.6 apparent magnitude....	+7.3
1910	DI Lacertae DI Lacertae DI Lacertae or Nova Lacertae 1910 was a nova which lit up in the constellation Lacerta in 1910. It reached a brightness of 4.6 apparent magnitude....	+4.6
1912	DN Geminorum DN Geminorum DN Geminorum or Nova Geminorum 1912 was a nova which lit up in 1912 in the constellation Gemini . It reached a brightness of 3.5 apparent magnitude....	+3.5
1918	V603 Aquilae V603 Aquilae V603 Aquilae was a bright nova occurring in Aquila in 1918.It reached a apparent magnitude of −1.4, and was the brightest nova of modern times....	-1.4
1919	HR Lyrae HR Lyrae HR Lyrae or Nova Lyrae 1919 was a nova which occurred in the constellation Lyra in 1919 with a brightness of 6.5 apparent magnitude....	+6.5
1919	V849 Ophiuchi V849 Ophiuchi V849 Ophiuchi or Nova Ophiuchi 1919 was a nova that lit up in 1919 in the constellation Ophiuchus and reached a brightness of 7.4 apparent magnitude....	+7.4
1920	V476 Cygni V476 Cygni V476 Cygni or Nova Cygni 1920 was a nova which occurred in the constellation Cygnus in 1920. It reached a brightness of 2.0 apparent magnitude....	+2.0
1920	T Pyxidis T Pyxidis T Pyxidis is a recurrent nova and nova remnant in the constellation Pyxis. Its usual apparent magnitude is 15.5, but there occurred eruptions with maximal apparent magnitude of about 7.0 in the years 1890, 1902, 1920, 1944 and 1966....	+6.4
1925	RR Pictoris RR Pictoris RR Pictoris was a nova, which lit up in the constellation Pictor in 1925. RR Pictoris reached a brightness of 1.2 apparent magnitude. The brightness of RR Pictoris decreased in 150 days by 3 mag....	+1.2
1927	EL Aquilae	+5.5
1927	XX Tauri	+5.9
1933	RS Ophiuchi RS Ophiuchi RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....	+4.3
1934	DQ Herculis DQ Herculis DQ Herculis was a slow, bright nova occurring in Hercules in December 1934. It reached apparent magnitude 1.5.DQ Herculis is the prototype for a category of cataclysmic variable stars called intermediate polars....	+1.4
1936	CP Lacertae CP Lacertae CP Lacertae was a nova, which lit up in 1936 in the constellation Lacerta. It reached a brightness of 2.1 apparent magnitude. The brightness of CP Lacertae decreased after the outbreak in 9 days by 3 mag....	+2.1
1936	V368 Aquilae	+5.0
1939	BT Monocerotis BT Monocerotis BT Monocerotis was a nova, which lit up in the constellation Monoceros in 1939. BT Monocerotis reached a brightness of 4.5 apparent magnitude. Its brightness decreased after the outbreak in 36 days by 3 mag....	+4.5
1942	V450 Cygni	+7.0
1942	CP Puppis CP Puppis CP Puppis was a bright nova occurring in the constellation Puppis in 1942.CP Puppis reached apparent magnitude 0.3.Coordinates* Right ascension: 08h 11m 46s...	+0.3
1943	V500 Aquilae V500 Aquilae V500 Aquilae or Nova Aquilae 1943 was a nova which appaeared in the constellation Aquila in 1943 and reached a brightness of 6.1 apparent magnitude....	+6.1
1944	T Pyxidis T Pyxidis T Pyxidis is a recurrent nova and nova remnant in the constellation Pyxis. Its usual apparent magnitude is 15.5, but there occurred eruptions with maximal apparent magnitude of about 7.0 in the years 1890, 1902, 1920, 1944 and 1966....	+7.1
1945	V528 Aquilae	+7.0
1946	T Coronae Borealis T Coronae Borealis T Coronae Borealis, informally nicknamed the Blaze Star, is a recurring nova in the constellation Corona Borealis.It normally has a apparent magnitude of about 10, but erupted twice, in 1866 and 1946, reaching magnitude 2.0....	+3.0
1948	CT Serpentis	+6.0
1948	V465 Cygni	+7.3
1950	DK Lacertae DK Lacertae DK Lacertae was a nova, which lit up in the constellation Lacerta in 1950. DK Lacertae reached apparent magnitude 5.0....	+5.0
1956	RW Ursae Minoris	+6.0
1958	RS Ophiuchi RS Ophiuchi RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....	+5.0
1960	V446 Herculis V446 Herculis V446 Herculis was a nova in the constellation Hercules in 1960. It reached apparent magnitude 2.8....	+2.8
1963	V533 Herculis V533 Herculis V533 Herculis was a nova which occurred in 1963 in the constellation Hercules . It reached apparent magnitude 3....	+3.0
1964	QZ Aurigae	+6.0
1967	T Pyxidis T Pyxidis T Pyxidis is a recurrent nova and nova remnant in the constellation Pyxis. Its usual apparent magnitude is 15.5, but there occurred eruptions with maximal apparent magnitude of about 7.0 in the years 1890, 1902, 1920, 1944 and 1966....	+6.7
1967	HR Delphini	+3.7
1967	RS Ophiuchi RS Ophiuchi RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....	+5.0
1968	LV Vulpeculae	+5.2
1970	FH Serpentis FH Serpentis FH Serpentis was a nova, which appeared in the constellation Serpens in 1970. It reached apparent magnitude 4.4....	+4.4
1970	V1229 Aquilae	+6.7
1970	V1330 Cygni	+7.5
1971	IV Cephei	+7.0
1975	V1500 Cygni V1500 Cygni V1500 Cygni or Nova Cygni 1975 was a bright nova occurring in 1975 in the constellation Cygnus .V1500 Cygni reached apparent magnitude 1.7....	+1.7
1975	V373 Scuti V373 Scuti V373 Scuti was a nova, which appeared in 1975 in the constellation Scutum and reached apparent magnitude 6....	+6.0
1976	NQ Vulpeculae NQ Vulpeculae NQ Vulpeculae was a nova with a maximum brightness of 6th apparent magnitude appearing in the constellation Vulpecula....	+6.0
1977	HS Sagittae	+7.2
1978	V1668 Cygni V1668 Cygni V1668 Cygni was a nova that appeared in the constellation Cygnus in 1978 with a maximum brightness of 6th apparent magnitude.Coordinates...	+6.0
1982	V1370 Aquilae	+6.0
1984	PW Vulpeculae	+6.4
1984	QU Vulpeculae QU Vulpeculae QU Vulpeculae was a nova, which occurred in 1984 in the constellation Vulpecula and which reached a brightness of 5.2 apparent magnitude....	+5.2
1985	RS Ophiuchi RS Ophiuchi RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....	+5.4
1986	V842 Centauri V842 Centauri V842 Centauri was a nova which occurred in 1986 in the constellation Centaurus and which reached a brightness of 4.6 apparent magnitude....	+4.6
1986	OS Andromedae	+6.3
1987	V827 Herculis	+7.5
1987	QV Vulpeculae	+7.0
1991	V838 Herculis V838 Herculis V838 Herculis was a nova which occurred in the constellation Hercules in 1991 and which reached apparent magnitude 5.0....	+5.0
1992	V1974 Cygni V1974 Cygni V1974 Cygni or Nova Cygni 1992 was a relatively bright nova in the constellation Cygnus .It was discovered on February 19, 1992 by Peter Collins ....	+4.2
1993	V705 Cassiopeiae	+5.8
1999	V382 Velorum V382 Velorum V382 Velorum was a bright nova, which occurred in 1999 in the southern constellation Vela . V382 Velorum reached a brightness of 2.6 apparent magnitude....	+2.6
1999	V1494 Aquilae V1494 Aquilae V1494 Aquilae or NOVA Aquilae 1999 b was a nova which occurred in 1999 in the constellation Aquila and which reached a brightness of 4.0 apparent magnitude....	+4.0
2006	RS Ophiuchi RS Ophiuchi RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....	+4.5
2007	V1280 Scorpii V1280 Scorpii V1280 Scorpii is a nova observed in February 2007 in the constellation Scorpius, just south of Messier 62. The nova was a 9th apparent magnitude object when it was discovered around February 4, and peaked at magnitude 3.9 on February 17....	+3.9 ,

A more complete list of novae in the Milky Way since 1612 is maintained by the Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams

The Central Bureau for Astronomical Telegrams is the official international clearing house for information relating to transient astronomical events....
, CBAT

Recurrent novae

RS Ophiuchi
RS Ophiuchi

RS Ophiuchi is a nova approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5....
T Coronae Borealis
T Coronae Borealis

T Coronae Borealis, informally nicknamed the Blaze Star, is a recurring nova in the constellation Corona Borealis.It normally has a apparent magnitude of about 10, but erupted twice, in 1866 and 1946, reaching magnitude 2.0....
T Pyxidis
T Pyxidis

T Pyxidis is a recurrent nova and nova remnant in the constellation Pyxis. Its usual apparent magnitude is 15.5, but there occurred eruptions with maximal apparent magnitude of about 7.0 in the years 1890, 1902, 1920, 1944 and 1966....

External links

, Sternberg Astronomical Institute
Sternberg Astronomical Institute

The Sternberg Astronomical Institute , also known as GAISh , is a research institution in Moscow, Russia, a division of Moscow State University....
, Moscow
Moscow

Moscow is the capital and the largest types of inhabited localities in Russia of the Russian Federation. It is also the largest European cities and metropolitan areas, with the Moscow metropolitan area ranking among the largest urban areas in the world....

Nova

Occurrence rate, and astrophysical significance

Historical significance

Novae as distance indicators

Bright novae since 1890

Recurrent novae

See also

External links