A visual band light curve for the April 1989 superoutburst of SU Ursae Majoris, adapted from Udalski et al. (1990)[1]
Observation data Epoch J2000 Equinox J2000
Constellation
Ursa Major
Right ascension
08h 12m 28.26946s[2]
Declination
+62° 36′ 22.4280″[2]
Apparent magnitude (V)
10.8–14.96[3]
Characteristics
Variable type
SU UMa[3]
Astrometry
Radial velocity (Rv)
+27.0[4] km/s
Proper motion (μ)
RA: +6.582[2] mas/yr Dec.: −24.538[2] mas/yr
Parallax (π)
4.5347 ± 0.0286 mas[2]
Distance
719 ± 5 ly (221 ± 1 pc)
Absolute magnitude (MV)
+5.1[5]
Orbit[6]
Period (P)
0.076351±0.000043 d
Inclination (i)
42[5]°
Periastron epoch (T)
2,446,143.6672±0.0015 HJD
Semi-amplitude (K1) (primary)
59±7 km s–1 km/s
Details
White dwarf
Mass
0.8[7]M☉
Temperature
28,000[7] K
Red dwarf
Mass
0.105[8]M☉
Radius
0.167[8]R☉
Other designations
AAVSO 0803+62, SU UMa, 2MASS J08122826+6236224[9]
Database references
SIMBAD
data
SU Ursae Majoris, or SU UMa, is a close binary star in the northern circumpolar constellation of Ursa Major. It is a periodic cataclysmic variable that varies in magnitude from a peak of 10.8 down to a base of 14.96.[3] The distance to this system, as determined from its annual parallax shift of 4.53 mas,[2] is 719 light-years. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.[4]
The variable nature of this star was discovered at the Moscow Observatory by Lidiya Tseraskaya (L. Ceraski) in 1908.[10] It was classified as a U Geminorum-type variable, or dwarf nova.[11] Observation since 1926 showed that this variable undergoes two different types of eruptions: a short maxima lasting around two days that ranged in brightness between 11.6–12.9 magnitude, and a longer maxima extending for 13 days that ranged between 10.4–11.8 magnitude. The later event came to be referred to as 'supermaxima'.[12] Similar dwarf novae of this class have since been discovered, and SU UMa is now the prototype for this sub-category of variable stars.[13]
This is a single-lined spectroscopic binary with an orbital period of 1.83 hours.[6] It consists of a white dwarf star that is acquiring matter from its close companion via an accretion disk. This disk is unstable and undergoes periodic outbursts which increase the luminosity of the system.[14] For SU UMa, the accretion rate from the companion is 9.8×10−13M☉·yr−1.[15] X-ray emission has been detected in the vicinity of the white dwarf, which drops by a factor of four during outbursts. This emission is theorized to come from the boundary layer between the white dwarf and its accretion disk.[14]
^Cite error: The named reference Udalski was invoked but never defined (see the help page).
^ abcdefCite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
^ abcCite error: The named reference gcvs was invoked but never defined (see the help page).
^ abCite error: The named reference Duflot1995 was invoked but never defined (see the help page).
^ abCite error: The named reference patterson was invoked but never defined (see the help page).
^ abCite error: The named reference Thorstensen1986 was invoked but never defined (see the help page).
^ abCite error: The named reference urban was invoked but never defined (see the help page).
^ abCite error: The named reference knigge was invoked but never defined (see the help page).
^Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
^Cite error: The named reference Ceraski1908 was invoked but never defined (see the help page).
^Cite error: The named reference Kraft1965 was invoked but never defined (see the help page).
^Cite error: The named reference Isles1974 was invoked but never defined (see the help page).
^Cite error: The named reference vanParadijs1983 was invoked but never defined (see the help page).
^ abCite error: The named reference Collins2010 was invoked but never defined (see the help page).
^Cite error: The named reference Zead2017 was invoked but never defined (see the help page).
SUUrsaeMajoris, or SU UMa, is a close binary star in the northern circumpolar constellation of Ursa Major. It is a periodic cataclysmic variable that...
"super-outbursts," in addition to normal outbursts. Varieties of SUUrsaeMajoris star include ER UrsaeMajoris stars and WZ Sagittae stars (UGWZ). Z Camelopardalis...
Iota UrsaeMajoris (ι UrsaeMajoris, abbreviated Iota UMa, ι UMa), also named Talitha /ˈtælɪθə/, is a star system in the northern circumpolar constellation...
Phecda /ˈfɛkdə/, also called Gamma UrsaeMajoris (γ UrsaeMajoris, abbreviated Gamma UMa, γ UMa), is a star in the constellation of Ursa Major. Since 1943...
Lambda UrsaeMajoris (λ UrsaeMajoris, abbreviated Lambda UMa, λ UMa), formally named Tania Borealis /ˈteɪniə ˌbɒriˈælɪs/, is a star in the northern circumpolar...
Major, abbreviated ER UMa. It is a prototype system for a subclass of SUUrsaeMajoris dwarf novae. The system ranges in brightness from a peak apparent visual...
Chi UrsaeMajoris or χ UrsaeMajoris, formally named Taiyangshou /ˌtaɪˌjæŋˈʃoʊ/, is a single star in the northern circumpolar constellation of Ursa Major...
"Little Dipper". Two of its stars, named Dubhe and Merak (α UrsaeMajoris and β UrsaeMajoris), can be used as the navigational pointer towards the place...
SW UrsaeMajoris is a cataclysmic binary star system in the northern circumpolar constellation of Ursa Major, abbreviated SW UMa. During quiescence it...
TV Corvi, also known as Tombaugh's Star, is a dwarf nova of the SUUrsaeMajoris type in the constellation Corvus that was first discovered by accident...
BZ UrsaeMajoris is a dwarf nova star system in the northern circumpolar constellation of Ursa Major. It consists of a white dwarf primary in a close...
Period of the SUUrsaeMajoris Star EK Trianguli Australis and Evidence for Ring-Like Accretion Disks in Long-Supercycle Length SUUrsaeMajoris Stars", Publications...
most stable celestial clock. SX Leonis Minoris is a dwarf nova of the SUUrsaeMajoris type that was identified in 1994. It consists of a white dwarf and...
system is similar to ER UrsaeMajoris, showing superoutbursts and superhumps. This indicates that RZ LMi is a SUUrsaeMajoris-type dwarf novae belonging...
standstills are seen, part way between maximum and minimum brightness. SUUrsaeMajoris stars, which undergo both frequent small outbursts, and rarer but larger...
the orbital period of the system. Superhumps were first seen in SUUrsaeMajoris (SU UMa) stars, a subclass of dwarf novae, at times when the binary system...
Sigma1 UrsaeMajoris (σ1 UMa) is the Bayer designation for a solitary star in the northern circumpolar constellation of Ursa Major. With an apparent visual...
understood to be coming from the same object. It is classified as a SUUrsaeMajoris variable subclass of dwarf nova in that it has both 'normal' outbursts...
most important discovery was the phenomenon of "super-humps" in the SUUrsaeMajoris class of cataclysmic binary stars in 1974. In 1988, the observatory...
c UrsaeMajoris is the Bayer designation for a double-lined spectroscopic binary star system in the northern constellation of Ursa Major. It has an apparent...
Association of Variable Star Observers also mentions YZ Leonis Minoris as a SUUrsaeMajoris-type star (dwarf nova). YZ Leonis Minoris was the first system discovered...
Located 3° northeast of Gamma is the VW Hydri, a dwarf nova of the SUUrsaeMajoris type. It is a close binary system that consists of a white dwarf and...
stars Temporarily "halt" at a particular brightness below their peak SUUrsaeMajoris stars Have "superoutbursts" which are brighter than the average SS...
in the constellation Triangulum Australe. It is a dwarf nova of the SUUrsaeMajoris type that officially classified as such in 1980, after the characteristic...
still not fully understood. Another outbursting star is AY Lyrae, an SUUrsaeMajoris-type dwarf nova that has undergone several superoutbursts. Of the same...
Comae Berenices. A June 2003 outburst from GO Comae Berenices, an SUUrsaeMajoris-type dwarf nova, was photometrically observed. Coma Berenices has seven...
VW Hydri is a dwarf nova of the SUUrsaeMajoris type in the deep southern constellation Hydrus; a star system that consists of a white dwarf and another...
Global Information