IM Normae

IM Normae is a recurrent nova in the constellation Norma, one of only ten known in the Milky Way. It has been observed to erupt in 1920 and 2002, reaching magnitude 8.5 from a baseline of 18.3. It was poorly monitored after the first eruption, so it is possible that it erupted in between these dates.[5]

IM Normae

Observation data Epoch J2000      Equinox J2000
Constellation	Norma
Right ascension	15^h 39^m 26.465^s[1]
Declination	−52° 19′ 17.99″
Characteristics
Spectral type	white dwarf + ?
Variable type	eclipsing recurrent nova (NR+E)
Astrometry
Parallax (π)	0.9946 ± 0.4149[2] mas
Distance	approx. 3,000 ly (approx. 1,000 pc)
Absolute magnitude (MV)	−4.4[3]
Details
White dwarf
Mass	1.21[4] M☉
Other designations
AAVSO 1532-52, Nova Normae 1920[1]
Database references
SIMBAD	data

At minimum, IM Normae shows brightness variations of about 0.3 magnitudes. These consist of 0.2 magnitude dips that are interpreted as partial eclipses of the accretion disk, and continuous variations caused by one side of the secondary star being heated by the white dwarf and therefore brighter than the other face. The orbital period is 2.462 hours.[6]

References

1. "V* IM Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 26 April 2015.
2. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
3. Schaefer, Bradley E. (2018). "The distances to Novae as seen by Gaia". Monthly Notices of the Royal Astronomical Society. 481 (3): 3033–3051. arXiv:1809.00180. Bibcode:2018MNRAS.481.3033S. doi:10.1093/mnras/sty2388. S2CID 118925493.
4. Shara, Michael M.; Prialnik, Dina; Hillman, Yael; Kovetz, Attay (2018). "The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae". The Astrophysical Journal. 860 (2): 110. arXiv:1804.06880. Bibcode:2018ApJ...860..110S. doi:10.3847/1538-4357/aabfbd. S2CID 55851634.
5. Schaefer, Bradley E. (2010). "Comprehensive Photometric Histories of All Known Galactic Recurrent Novae". The Astrophysical Journal Supplement. 187 (2): 275–373. arXiv:0912.4426. Bibcode:2010ApJS..187..275S. doi:10.1088/0067-0049/187/2/275. S2CID 119294221.
6. Woudt, P. A.; Warner, B. (2003). "High-speed photometry of the recurrent nova IM Normae". Monthly Notices of the Royal Astronomical Society. 343 (1): 313–314. arXiv:astro-ph/0304002. Bibcode:2003MNRAS.343..313W. doi:10.1046/j.1365-8711.2003.06666.x. S2CID 17271577.