NGC 4457 is an intermediate

spiral galaxy Spiral galaxies form a galaxy morphological classification, 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 (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s away 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 first constellati ...

Virgo Virgo may refer to: Arts and entertainment * Virgo (film), a 1970 Egyptian film * Virgo (character), several Marvel Comics characters * Virgo Asmita, a character in the manga ''Saint Seiya: The Lost Canvas'' * ''Virgo'' (album), by Virgo Four, ...

. It is also classified as a

LINER Liner or LINER may refer to: Line drawing * Eye liner, a type of makeup * Marker pen, a porous-tip pen with its own ink source * Multiple lining tool used in engraving * A sable brush used by coach painters Linings * Acoustic liner, a no ...

galaxy, a class of

active galaxy An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such e ...

defined by their spectral line emissions. NGC 4457 Is inclined by about 33°. It was discovered by astronomer

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

on February 23, 1784. Despite being listed in the Virgo Cluster Catalog as VCC 1145, NGC 4457 is a member of the

Virgo II Groups The Virgo II Groups, also known as the Virgo II Cloud, Virgo Southern Extension, or the Virgo S Cloud, are a series of at least 100 galactic clusters and individual galaxies stretching approximately off the southern edge of the Virgo Supercluste ...

which form an extension of the

Virgo cluster The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the Virgo constellation. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the larger ...

. NGC 4457 may have had a recent minor merger with another galaxy.

Supernova

On July 1 2020, an

astronomical transient Time-domain astronomy is the study of how astronomical objects change with time. Said to have begun with Galileo's '' Letters on Sunspots'', the field has now naturally expanded to encompass variable objects beyond the Solar System. Temporal varia ...

was discovered in NGC 4457 by astronomer

Kōichi Itagaki is an amateur astronomer based in Yamagata, the capital city of Yamagata Prefecture in the Tōhoku region of northern Honshu island, Japan. He is responsible for discovering many comets, and over 170 supernovae.ASAS-SN The All Sky Automated Survey for SuperNovae (ASAS-SN) is an automated program to search for new supernovae and other astronomical transients, headed by astronomers from the Ohio State University, including Christopher Kochanek and Krzysztof Stan ...

. Spectroscopic classification determined the object to be 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 ...

, designated SN2020nvb.

Physical characteristics

NGC 4457 has a broad oval zone containing an inner spiral which is defined mainly by two fairly open arms. There is a well-defined outer ring that is completely detached from the inner regions of the galaxy.

Truncated disk

NGC 4457 has a severely reduced amount of star-formation in its disk while its inner regions have a normalized rate of massive star formation. This may have been caused by a recent interaction of the

gas Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

in the galaxy with the

in the surrounding

Virgo Cluster The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the Virgo constellation. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the larger ...

, causing the gas to be stripped away in an effect known as

ram-pressure stripping Ram pressure is a pressure exerted on a body moving through a fluid medium, caused by relative bulk motion of the fluid rather than random thermal motion. It causes a drag force to be exerted on the body. Ram pressure is given in tensor form as ...

References

External links

Sasmirala page on NGC 4457
{{DEFAULTSORT:NGC 4457 Intermediate spiral galaxies LINER galaxies Virgo (constellation) 4457 041101 07609 Astronomical objects discovered in 1784 Discoveries by William Herschel

Supernova

Physical characteristics

Truncated disk

See also

References

External links