SN 2003gd was a

Type II-P supernova A Type II supernova (plural: ''supernovae'' or ''supernovas'') results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, but no more than 40 to 50 times, the mass of the Sun () to undergo th ...

explosion in the spiral galaxy

Messier 74 Messier 74 (also known as NGC 628 and Phantom Galaxy) is a large spiral galaxy in the equatorial constellation Pisces. It is about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used a ...

, located 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 ...

Pisces Pisces may refer to: * Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish * Pisces (astrology), an astrological sign * Pisces (constellation), a constellation **Pisces Overdensity, an overdensity of stars in ...

. SN 2003gd was discovered on 12 June 2003 by

Robert Evans Robert Evans (born Robert J. Shapera; June 29, 1930October 26, 2019) was an American film producer, studio executive, and actor, best known for his work on '' Rosemary's Baby'' (1968), '' Love Story'' (1970), ''The Godfather'' (1972), and ''Chi ...

, using a 0.31m

reflector Reflector may refer to: Science * Reflector, a device that causes reflection (for example, a mirror or a retroreflector) * Reflector (photography), used to control lighting contrast * Reflecting telescope * Reflector (antenna), the part of an ant ...

, and its discovery was confirmed on 13 June 2003 by R. H. McNaught using the 1.0m telescope at the

Siding Spring Observatory Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a coll ...

. This supernova was located along the outer edge of a

spiral arm Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''light curve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

, this appears to be a normal Type II-p. A

light echo 309x309px, Reflected light following path B arrives shortly after the direct flash following path A but before light following path C. B and C have the same apparent distance from the star as seen from Earth.">Earth.html" ;"title="apparent distan ...

from nearby dust was detected in archival images from 2004.

had been observed approximately 200 days before the explosion with the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

, and about 300 days before using the

Gemini Telescope The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes prov ...

. Astronomers were able to identify an object in these pre-supernova images that was in the same position as SN 2003gd, and which is believed to be the supernova's progenitor star. This progenitor star was a

red supergiant Red supergiants (RSGs) are stars with a supergiant luminosity class ( Yerkes class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelgeuse and Anta ...

with a mass of , consistent with the expectations of existing single-star

stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is cons ...

models. It is the first progenitor of a normal type II-P supernova to have ever been detected.

References

External links

Light curves and spectra
on th
Open Supernova Catalog

Image of SN 2003gd
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Entry for SN 2003gd in the SIMBAD database
Supernovae Supernova remnants Pisces (constellation) 20030612