Z Ursae Minoris

Z Ursae Minoris
	; A visual band light curve for Z Ursae Minoris, plotted from AAVSO data
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Ursa Minor
Right ascension	15h 02m 01.36335s
Declination	+83° 03′ 48.6299″
Apparent magnitude (V)	10.8 - 19.0
Characteristics
Spectral type	C (R)
Variable type	R CrB
Astrometry
Radial velocity (Rv)	−36.07±0.98 km/s
Proper motion (μ)	RA: −7.346 mas/yr ; Dec.: +4.322 mas/yr
Parallax (π)	0.2159 ± 0.0231 mas
Distance	approx. 15,000 ly ; (approx. 4,600 pc)
Details
Mass	0.7±0.2 M☉
Luminosity	7,900+12,000; −4,800 L☉
Surface gravity (log g)	0.5±0.3 cgs
Temperature	5,250±250 K
Metallicity	−1.85 dex
Other designations
	Z UMi, TYC 4634-1727-1, 2MASS J15020132+8303485
Database references
SIMBAD	data

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]

References

^ "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.
^ ^a ^b ^c ^d ^e ^f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
^ ^a ^b ^c "Z UMi". The International Variable Star Index. Retrieved 2019-10-09.
^ Alksnis, A.; Balklavs, A.; Dzervitis, U.; Eglitis, I.; Paupers, O.; Pundure, I. (2001). "General Catalog of Galactic Carbon Stars by C. B. Stephenson. Third Edition". Baltic Astronomy. 10 (1–2): 1–318. Bibcode:2001BaltA..10....1A. doi:10.1515/astro-2001-1-202.
^ ^a ^b ^c ^d ^e ^f Kipper, Tõnu; Klochkova, Valentina G. (2006). "A Cool R Coronae Borealis Star Z UMi". Baltic Astronomy. 15: 531–37. arXiv:0706.3271. Bibcode:2006BaltA..15..531K.
^ "Z Ursae Minoris". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-09.
^ ^a ^b Goswami, A.; Rao, N. K.; Lambert, D. L.; Gonzalez, G. (1997). "On the Hydrogen Deficient Nature of Z UMi". Publications of the Astronomical Society of the Pacific. 109: 796. Bibcode:1997PASP..109..796G. doi:10.1086/133946.
^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
^ Stephenson, C. B. (1985). "New carbon stars found in a hemispheric survey". The Astronomical Journal. 90: 784. Bibcode:1985AJ.....90..784S. doi:10.1086/113787.
^ Benson, Priscilla J.; Clayton, Geoffrey C.; Garnavich, Peter; Szkody, Paula (1994). "Z Ursa Minoris -- a new R Coronae Borealis variable". The Astronomical Journal. 108 (1): 247–50. Bibcode:1994AJ....108..247B. doi:10.1086/117063.

Zdroj:https://en.wikipedia.org?pojem=Z_Ursae_Minoris
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[aavso-1] "Download Data". aavso.org. AAVSO. Retrieved 1 October 2021.

[Gaia_DR3-2] ^ ^a ^b ^c ^d ^e ^f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[vsx-3] "Z UMi". The International Variable Star Index. Retrieved 2019-10-09.

[alksnis-4] Alksnis, A.; Balklavs, A.; Dzervitis, U.; Eglitis, I.; Paupers, O.; Pundure, I. (2001). "General Catalog of Galactic Carbon Stars by C. B. Stephenson. Third Edition". Baltic Astronomy. 10 (1–2): 1–318. Bibcode:2001BaltA..10....1A. doi:10.1515/astro-2001-1-202.

[kipper-5] ^ ^a ^b ^c ^d ^e ^f Kipper, Tõnu; Klochkova, Valentina G. (2006). "A Cool R Coronae Borealis Star Z UMi". Baltic Astronomy. 15: 531–37. arXiv:0706.3271. Bibcode:2006BaltA..15..531K.

[Simbad-6] "Z Ursae Minoris". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-09.

[goswami-7] Goswami, A.; Rao, N. K.; Lambert, D. L.; Gonzalez, G. (1997). "On the Hydrogen Deficient Nature of Z UMi". Publications of the Astronomical Society of the Pacific. 109: 796. Bibcode:1997PASP..109..796G. doi:10.1086/133946.

[gcvs-8] Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.

[stephenson-9] Stephenson, C. B. (1985). "New carbon stars found in a hemispheric survey". The Astronomical Journal. 90: 784. Bibcode:1985AJ.....90..784S. doi:10.1086/113787.

[benson-10] Benson, Priscilla J.; Clayton, Geoffrey C.; Garnavich, Peter; Szkody, Paula (1994). "Z Ursa Minoris -- a new R Coronae Borealis variable". The Astronomical Journal. 108 (1): 247–50. Bibcode:1994AJ....108..247B. doi:10.1086/117063.

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Observation data Epoch J2000.0 Equinox J2000.0
A visual band light curve for Z Ursae Minoris, plotted from AAVSO data^[1]
Constellation	Ursa Minor
Right ascension	15^h 02^m 01.36335^s^[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 (R_v)	−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]
Distance	approx. 15,000 ly (approx. 4,600 pc)

Details

Mass	0.7±0.2^[5] `M`_☉
Luminosity	7,900+12,000 −4,800^[5] `L`_☉
Surface gravity (log g)	0.5±0.3^[5] cgs
Temperature	5,250±250^[5] K
Metallicity	−1.85^[5] dex

Other designations
Z UMi, TYC 4634-1727-1, 2MASS J15020132+8303485^[6]
Database references
SIMBAD	data