S Ursae Minoris

S Ursae Minoris (S UMi) is a Mira variable star in the constellation Ursa Minor, ranging from magnitude 7.5 to fainter than 13.2 over a period of 331 days.^[2]

ConstellationUrsa Minor^[2]

Right ascension15^h 29^m 34.5775^s[3]

Declination+78° 38′ 00.274″^[3]

Apparentmagnitude(V)7.5-<13.2^[2]

Quick facts Constellation, Right ascension ...

S Ursae Minoris

The visual band light curve of S Ursae Minoris, from AAVSO data[1]
Observation data Epoch J2000      Equinox ICRS
Constellation	Ursa Minor[2]
Right ascension	15h 29m 34.5775s[3]
Declination	+78° 38′ 00.274″[3]
Apparent magnitude (V)	7.5-<13.2[2]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	M6e-M9e[2]
Variable type	Mira[2]
Astrometry
Proper motion (μ)	RA: −30.986±0.303[3] mas/yr Dec.: 7.006±0.309[3] mas/yr
Parallax (π)	2.5455±0.1578 mas[3]
Distance	1,280 ± 80 ly (390 ± 20 pc)
Details
Mass	2.3[5] M☉
Radius	744[6] R☉
Luminosity	3,896[4] L☉
Surface gravity (log g)	1.63[5] cgs
Temperature	3,457[5] K
Other designations
S UMi, HD 139492, HIP 75847[7]
Database references
SIMBAD	data

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Williamina Fleming discovered that the star's brightness varies, in 1895.^[8]