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]
^ abcEnglish, Jayanne; Irwin, Judith A. (June 1997), "The Ionized Gas and Radio Halo of NGC 3432 (ARP 206)", Astronomical Journal, 113: 2006–2024, Bibcode:1997AJ....113.2006E, doi:10.1086/118413.
^Wagner, R. M.; et al. (April 2004), "Discovery and Evolution of an Unusual Luminous Variable Star in NGC 3432 (Supernova 2000ch)", The Publications of the Astronomical Society of the Pacific, 116 (818): 326–336, arXiv:astro-ph/0404035, Bibcode:2004PASP..116..326W, doi:10.1086/382997.
Bertola, F. (1966), "Mass and luminosity distribution in galaxies NGC 3432, NGC 4485-90 and NGC 4605.", Memorie della Societa Astronomica Italiana, 37: 433–458, Bibcode:1966MmSAI..37..433B.