SS Ursae Minoris is a cataclysmic variable star system in the constellation Ursa Minor. It was discovered visually and by its X-ray emissions separately in 1982 before they were understood to be coming from the same object.[5] It is classified as a SU Ursae Majoris variable subclass of dwarf nova in that it has both 'normal' outbursts of increased brightness as well as even brighter 'superoutbursts'. However, unlike other SU Ursae Majoris stars, the superoutbursts are of longer duration than the regular outbursts.[3]

SS Ursae Minoris

A visual band light curve for SS Ursae Minoris. The main plot shows a superoutburst, and the inset plot shows superhumps seen on April 8-9, 1998. Adapted from Kato et al. (1998)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Minor
Right ascension 15h 51m 22.3401s[2]
Declination +71° 45′ 11.8343″[2]
Characteristics
Variable type dwarf nova[3]
Astrometry
Proper motion (μ) RA: 13.085±0.080[2] mas/yr
Dec.: −12.260±0.088[2] mas/yr
Parallax (π)1.8871 ± 0.0497 mas[2]
Distance1,730 ± 50 ly
(530 ± 10 pc)
Details
Other designations
Gaia DR2 1696309737421796352, 2MASS J15512233+7145118[4]
Database references
SIMBADdata

The two stars orbit each other every 98 minutes.[3]

References

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  1. ^ Kato, T.; Lipkin, Y.; Retter, A.; Leibowitz, E. (June 1998). "Observation of Superhumps in SS UMi". Information Bulletin on Variable Stars. 4602: 1. Bibcode:1998IBVS.4602....1K. Retrieved 27 April 2022.
  2. ^ a b c d e 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. ^ a b c Chen, J.-S.; Liu, X.-W.; Wei, M.-Z. (1991). "CCD photometry of the SU Ursae Majoris cataclysmic variable SS Ursae Minoris (PG 1551 + 719)". Astronomy and Astrophysics. 242 (2): 397–400. Bibcode:1991A&A...242..397C. ISSN 0004-6361.
  4. ^ "V* SS UMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-07.
  5. ^ Udalski, A. (1990). "SS Ursae Minoris: a Normal U Gem Type Dwarf Nova". Information Bulletin on Variable Stars. 3425 (3425): 1–4. Bibcode:1990IBVS.3425....1U.