Z Ursae Minoris

Z Ursae Minoris

A visual band light curve for Z Ursae Minoris, plotted from AAVSO data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Minor
Right ascension 15h 02m 01.36335s[2]
Declination +83° 03′ 48.6299″[2]
Apparent magnitude (V) 10.8 - 19.0[3]
Characteristics
Spectral type C[3] (R[4])
Variable type R CrB[3]
Astrometry
Radial velocity (Rv)−36.07±0.98[2] km/s
Proper motion (μ) RA: −7.346[2] mas/yr
Dec.: +4.322[2] mas/yr
Parallax (π)0.2159 ± 0.0231 mas[2]
Distanceapprox. 15,000 ly
(approx. 4,600 pc)
Details
Mass0.7±0.2[5] M☉
Luminosity7,900+12,000
−4,800[5] L☉
Surface gravity (log g)0.5±0.3[5] cgs
Temperature5,250±250[5] K
Metallicity [Fe/H]−1.85[5] dex
Other designations
Z UMi, TYC 4634-1727-1, 2MASS J15020132+8303485[6]
Database references
SIMBADdata

Z Ursae Minoris (Z UMi) is a carbon star and R Coronae Borealis variable in the constellation Ursa Minor.

Z Ursae Minoris was discovered to be a variable star in 1934.[7] It was catalogued as a probable Mira variable, due to its red colour and variations over several hundred days.[8] It was discovered to be a carbon star in a survey published in 1985,[9] and subsequently found also to be hydrogen-deficient.[7] After fading by almost six magnitudes in 1992, it was classified as an R Coronae Borealis variable.[10] It was confirmed as an R Coronae Borealis variable, one of the coolest in the class, after its spectrum was analysed in 2006.[5]

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  7. ^ a b Cite error: The named reference goswami was invoked but never defined (see the help page).
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  10. ^ Cite error: The named reference benson was invoked but never defined (see the help page).