NGC 3432 is an edge-on spiral galaxy that can be found in the northern constellation of Leo Minor.[6] It was discovered by German-British astronomer William Herschel on March 19, 1787.[7] This galaxy is located at a distance of 40 million light-years (12.3 Mpc) from the Milky Way.[2] It is interacting with UGC 5983, a nearby dwarf galaxy, and features tidal filaments and intense star formation. Because of these features, it was listed in Halton Arp's Atlas of Peculiar Galaxies.[8]
NGC 3432 | |
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Observation data (J2000 epoch) | |
Constellation | Leo Minor |
Right ascension | 10h 52m 31.132s[1] |
Declination | +36° 37′ 07.60″[1] |
Heliocentric radial velocity | 613[2] |
Distance | 40.1 ± 5.8 Mly (12.30 ± 1.77 Mpc)[2] |
Apparent magnitude (V) | 11.3[3] |
Characteristics | |
Type | SB(s)m[4] |
Apparent size (V) | 6.5″ × 1.1″[3] |
Other designations | |
NGC 3432, Arp 206, UGC 5986, PGC 32643[5] |
The morphological classification of NGC 3432 is SB(s)m,[4] which indicates this is a barred Magellanic spiral galaxy (SB) with no inner ring structure (s) and an irregular appearance (m). The galaxy is inclined at an angle of 85°±2° to the plane of the sky[2] with its major axis along a positional angle 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.[4] The shape of the galaxy is distorted and two tidal tails have been identified. NGC 3432 has an active galactic nucleus of the LINER type with a nuclear HII region.[10]
In May 3, 2000, a candidate nova was detected in this galaxy.[11] It was located 123″ east and 180″ north of the galactic nucleus, and aligned with an H II region (or spiral arm) of the galaxy.[12] This appeared similar to a type IIn supernova (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.[13] The outburst was found comparable to an eruption of Eta Carinae in the mid–nineteenth century.[14] Multiple subsequent outbursts were observed in 2008 and 2009.[15] It is now classified as a supernova imposter, and is expected to become a core collapse supernova in the future.[16]