NGC 1309 is a

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away, appearing in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Eridanus. It is about 75,000

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

across, and is about 3/4s the width of the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

. Its shape is classified as SA(s)bc, meaning that it has moderately wound spiral arms and no ring. Bright blue areas of

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

can be seen in the spiral arms, while the yellowish central nucleus contains older-population

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

s. NGC 1309 is one of over 200 members of the

Eridanus Group The Eridanus Group, sometimes called the Eridanus Cloud, is a nearby loose grouping of galaxies at a mean distance of approximately 75 Mly (23 ± 2 Mpc) in the constellation Eridanus. Redshift values show that there are approximately 200 gal ...

of galaxies.

Supernova 2002fk

SN 2002fk was discovered jointly by Reiki Kushida of the Yatsugatake South Base Observatory, Nagano Prefecture, Japan; and Jun-jie Wang and Yu-Lei Qiu of the Beijing Astronomical Observatory on Sept. 17.719 UT. When it was discovered it was

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

~15.0; it was estimated to have reached maximum magnitude of ~13.0 before fading away. It was a

Type Ia supernova A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white ...

(i.e., the progenitor star was

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

). White dwarfs are older stars that have used up almost all of their main fuel (the lighter elements such as

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

and

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

). SN 2002fk's spectra showed no indications of hydrogen, helium or carbon; instead ionized calcium, silicon, iron and nickel were found.

Supernova 2012Z

SN 2012Z was discovered jointly by S. B. Cenko, W. Li, and A. V. Filippenko using the

Katzman Automatic Imaging Telescope The Katzman Automatic Imaging Telescope (KAIT) is an automated telescope used in the search for supernovae. The telescope had a first light in 1998, and is a noted robotic telescope. It had first recorded data in August 1996, and was formally ded ...

on January 29.15 UT as part of the

Lick Observatory Supernova Search The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by th ...

. The scientists have hypothesized that this is a type Iax supernova, and may have left behind a remnant

zombie star A zombie star is a hypothetical result of a Type Iax supernova which leaves behind a remnant star, rather than completely dispersing the stellar mass. Type Iax supernovae are similar to Type Ia, but have a lower ejection velocity and lower luminos ...

. In February 2022 a study with new observations has confirmed that the star survived the explosion and is even brighter than before.

References

External links

* {{DEFAULTSORT:NGC 1309 Unbarred spiral galaxies Eridanus (constellation) Eridanus Group

1309 Year 1309 (Roman numerals, MCCCIX) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. Events By place Europe * March 14 – Sultan Muhammad III of Granada, Muhammad III is depos ...

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