SN 2008ha
Encyclopedia
SN 2008ha was a type Ia
supernova
which was first observed around November 7, 2008 in the galaxy UGC 12682, which lies in the constellation Pegasus
at a distance of about 21.3 Mpc from Earth.
SN 2008ha was unusual in several ways: with an absolute V band magnitude
of −14.2 it is one of the faintest supernovae ever observed; its host galaxy type very rarely produces supernovae; and it was co-discovered by 14-year-old Caroline Moore
, Jack Newton and Tim Puckett, members of the Puckett Observatory
World Supernova Search. Moore is the second youngest person ever to find a supernova. The youngest is Kathryn Aurora Gray, who co-discovered super nova SN 2010lt
. Another unusual feature of SN 2008ha was its low expansion velocity of only ~2000 km/s at maximum brightness, which indicates a very small kinetic energy
released in the explosion. For comparison, SN 2002cx
expanded at a velocity of ~5000 km/s whereas typical
SN Ia
expand at around ~10,000 km/s. The low expansion velocity of SN2008ha resulted in relatively small Doppler broadening
of spectral emission lines and this led to higher quality data. The supernova was studied with ultraviolet, optical, and near-infrared photometry
as well as optical spectra, using the Magellan telescopes
in Chile, the MMT telescope
in Arizona
, the Gemini
and Keck telescopes in Hawaii, and NASA's Swift satellite
. Spectroscopically, SN 2008ha was identified as a SN 2002cx-type, a peculiar sub-class of SN Ia
. SN 2008ha had a brightness period of only 10 days, which is significantly shorter than that of other SN 2002cx-like objects (~15 days) or normal Ia supernovas (~20 days). From the peak luminosity and the brightness time it was estimated that SN 2008ha generated (3.0 ± 0.9) × 10−3 M⊙
of 56Ni
, had a kinetic energy of 2 × 1048 erg
s, and ejected 0.15 M⊙ of material.
Type Ia supernova
A Type Ia supernova is a sub-category of supernovae, which in turn are a sub-category of cataclysmic variable stars, that results from the violent explosion of a white dwarf star. A white dwarf is the remnant of a star that has completed its normal life cycle and has ceased nuclear fusion...
supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. 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...
which was first observed around November 7, 2008 in the galaxy UGC 12682, which lies in the constellation Pegasus
Pegasus (constellation)
Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
at a distance of about 21.3 Mpc from Earth.
SN 2008ha was unusual in several ways: with an absolute V band magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
of −14.2 it is one of the faintest supernovae ever observed; its host galaxy type very rarely produces supernovae; and it was co-discovered by 14-year-old Caroline Moore
Caroline Moore
Caroline Moore is an American amateur astronomer. On November 7, 2008, at the age of 14, Moore discovered supernova 2008ha in the galaxy UGC 12682 in the constellation Pegasus. At that time, Moore was the youngest person to discover a supernova...
, Jack Newton and Tim Puckett, members of the Puckett Observatory
Puckett Observatory
Puckett Observatory is a private astronomical observatory located in the North Georgia Mountains, near Ellijay, Georgia, United States. It is owned and operated by Tim Puckett. Its primary observation goals are the study of comets and the discovery of supernovae...
World Supernova Search. Moore is the second youngest person ever to find a supernova. The youngest is Kathryn Aurora Gray, who co-discovered super nova SN 2010lt
SN 2010lt
SN 2010lt is a supernova located in the galaxy UGC 3378 in Camelopardalis. It was discovered by amateur astronomers Kathryn Aurora Gray, her father Paul Gray, of Fredericton, New Brunswick, Canada and David J. Lane of Stillwater Lake, Nova Scotia, Canada. Upon discovery, Kathryn Aurora Gray became...
. Another unusual feature of SN 2008ha was its low expansion velocity of only ~2000 km/s at maximum brightness, which indicates a very small kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
released in the explosion. For comparison, SN 2002cx
SN 2002cx
SN 2002cx is a peculiar type Ia supernova. It was discovered in May 2002 by a team of researchers from LBL. It behaved differently than normal type Ia supernovae, and different from several other previously observed peculiar type Ia supernovae including SN 1991T and SN 1991bg.-Discovery:SN 2002cx...
expanded at a velocity of ~5000 km/s whereas typical
SN Ia
Type Ia supernova
A Type Ia supernova is a sub-category of supernovae, which in turn are a sub-category of cataclysmic variable stars, that results from the violent explosion of a white dwarf star. A white dwarf is the remnant of a star that has completed its normal life cycle and has ceased nuclear fusion...
expand at around ~10,000 km/s. The low expansion velocity of SN2008ha resulted in relatively small Doppler broadening
Doppler broadening
In atomic physics, Doppler broadening is the broadening of spectral lines due to the Doppler effect caused by a distribution of velocities of atoms or molecules. Different velocities of the emitting particles result in different shifts, the cumulative effect of which is the line broadening.The...
of spectral emission lines and this led to higher quality data. The supernova was studied with ultraviolet, optical, and near-infrared photometry
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...
as well as optical spectra, using the Magellan telescopes
Magellan telescopes
The Magellan Telescopes are a pair of 6.5 m diameter optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T...
in Chile, the MMT telescope
MMT Observatory
The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains...
in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, the Gemini
Gemini Observatory
The Gemini Observatory is an astronomical observatory consisting of two telescopes at sites in Hawai‘i and Chile. Together, the twin Gemini telescopes provide almost complete coverage of both the northern and southern skies...
and Keck telescopes in Hawaii, and NASA's Swift satellite
Swift Gamma-Ray Burst Mission
The Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on 20 November 2004, 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle. Swift is managed by the NASA Goddard Space Flight Center, and was developed by an international...
. Spectroscopically, SN 2008ha was identified as a SN 2002cx-type, a peculiar sub-class of SN Ia
Type Ia supernova
A Type Ia supernova is a sub-category of supernovae, which in turn are a sub-category of cataclysmic variable stars, that results from the violent explosion of a white dwarf star. A white dwarf is the remnant of a star that has completed its normal life cycle and has ceased nuclear fusion...
. SN 2008ha had a brightness period of only 10 days, which is significantly shorter than that of other SN 2002cx-like objects (~15 days) or normal Ia supernovas (~20 days). From the peak luminosity and the brightness time it was estimated that SN 2008ha generated (3.0 ± 0.9) × 10−3 M⊙
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
of 56Ni
Isotopes of nickel
Naturally occurring nickel is composed of five stable isotopes; , , , and with being the most abundant . 58Ni may decay by double beta-plus decay to 58Fe. 26 radioisotopes have been characterised with the most stable being with a half-life of 76,000 years, with a half-life of 100.1 years,...
, had a kinetic energy of 2 × 1048 erg
Erg
An erg is the unit of energy and mechanical work in the centimetre-gram-second system of units, symbol "erg". Its name is derived from the Greek ergon, meaning "work"....
s, and ejected 0.15 M⊙ of material.