NGC 3432

NGC 3432 is an edge-on spiral galaxy that can be found in the northern constellation of Leo Minor.^[7] It was discovered by German-British astronomer William Herschel on March 19, 1787.^[8] This galaxy is located at a distance of 40 million light-years (12.3 Mpc) from the Milky Way.^[3] 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.^[9]

Hubble image of NGC 3432 showing regions of star formation^[10]

NGC 3432
SDSS DR14 image of NGC 3432
Observation data (J2000 epoch)
Constellation	Leo Minor
Right ascension	10h 52m 31.132s[1]
Declination	+36° 37′ 07.60″[1]
Redshift	0.002055[2]
Heliocentric radial velocity	613[3]
Distance	40.1 ± 5.8 Mly (12.30 ± 1.77 Mpc)[3]
Apparent magnitude (V)	11.3[4]
Characteristics
Type	SB(s)m[5]
Size	~98,000 ly (30.05 kpc) (estimated)[2]
Apparent size (V)	6.5′ × 1.1′[4]
Other designations
IRAS 10497+3653, NGC 3432, Arp 206, UGC 5986, MCG +06-24-028, PGC 32643, CGCG 184-030, VV 011a[6][2]

The morphological classification of NGC 3432 is SB(s)m,^[5] 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^[3] 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.^[5] 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.^[11]

In May 3, 2000, a candidate nova was detected in this galaxy.^[12] 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.^[13] 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.^[14] The outburst was found comparable to an eruption of Eta Carinae in the mid–nineteenth century.^[15] Multiple subsequent outbursts were observed in 2008 and 2009.^[16] It is now classified as a supernova imposter, and is expected to become a core collapse supernova in the future.^[17]

See also

• List of NGC objects (3001–4000)