spiral galaxy
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''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 ...
of
Leo Minor
Leo Minor is a small and faint constellation in the northern celestial hemisphere. Its name is Latin for "the smaller lion", in contrast to Leo, the larger lion. It lies between the larger and more recognizable Ursa Major to the north and Le ...
. It was discovered by German-British astronomer
William Herschel
Frederick William Herschel (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline H ...
on March 19, 1787. This galaxy is located at a distance of from 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 ...
. It is
interacting
Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to:
Science
* Interaction hypothesis, a theory of second language acquisition
* Interaction (statistics)
* Interactions o ...
with UGC 5983, a nearby
dwarf galaxy
A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is ...
Halton Arp
Halton Christian "Chip" Arp (March 21, 1927 – December 28, 2013) was an American astronomer. He was known for his 1966 ''Atlas of Peculiar Galaxies'', which (it was later theorized) catalogues many examples of interacting and merging galaxie ...
's
Atlas of Peculiar Galaxies
The ''Atlas of Peculiar Galaxies'' is a catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology. The p ...
Magellanic spiral
Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm (and SAm, SBm, SABm). They are galaxies with one single spiral arm, and are named after their prototype, the Large Magellanic Cloud, an SBm galaxy. They ca ...
galaxy (SB) with no inner ring structure (s) and an irregular appearance (m). The galaxy is inclined at an angle of to the
plane of the sky
Plane(s) most often refers to:
* Aero- or airplane, a powered, fixed-wing aircraft
* Plane (geometry), a flat, 2-dimensional surface
Plane or planes may also refer to:
Biology
* Plane (tree) or ''Platanus'', wetland native plant
* ''Planes' ...
with its major axis along a
positional angle
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the d ...
of 38°, which means it is being viewed from nearly edge-on. It is interacting with the companion galaxy UGC 5983, which is creating features that extend outside the galactic plane, as well as an extended halo of radio emission. The shape of the galaxy is distorted and two
tidal tail
A tidal tail is a thin, elongated region of stars and interstellar gas that extends into space from a galaxy. Tidal tails occur as a result of galactic tide forces between interacting galaxies. Examples of galaxies with tidal tails include the ...
s have been identified. NGC 3432 has an
active galactic nucleus
An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not pr ...
of the
LINER
A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission. The spectra typically include line emission from weakly ionized or neutral atoms, such as O, O+, N+, and S+. ...
type with a nuclear
HII region
An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds ...
.
In May 3, 2000, a candidate nova was detected in this galaxy. It was located east and north of the galactic nucleus, and aligned with an H II region (or spiral arm) of the galaxy. This appeared similar to a
type IIn 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 ...
(designated SN 2000ch), but it peaked below the typical luminosity of these events. As such, it may have been a "superoutburst" of a luminous variable and thus it could have survived the event. The outburst was found comparable to an eruption of
Eta Carinae
Eta Carinae (η Carinae, abbreviated to η Car), formerly known as Eta Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around distant in t ...
in the mid–nineteenth century. Multiple subsequent outbursts were observed in 2008 and 2009. It is now classified as a
supernova imposter
Supernova impostors are stellar explosions that appear at first to be a supernova but do not destroy their progenitor stars. As such, they are a class of extra-powerful novae. They are also known as Type V supernovae, Eta Carinae analogs, and gia ...
, and is expected to become a
core collapse supernova
A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or whe ...