Epsilon Ursae Minoris

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Epsilon Ursae Minoris
Location of ε Ursae Minoris (circled)
Observation data
ICRS
)
Constellation Ursa Minor
Right ascension 16h 45m 58.24168s[1]
Declination +82° 02′ 14.1233″[1]
Apparent magnitude (V) +4.19[2]
Characteristics
Spectral type G5 III + A8-F0 V[3]
U−B color index +0.55[4]
B−V color index +0.89[4]
Variable type
RS CVn[5]
Distance
300 ± 10 ly
(93 ± 3 pc)
Absolute magnitude (MV)−0.922[7]
Semi-amplitude
(K1)
(primary)		31.8 km/s
Details
ε UMi A
Rotational velocity (v sin i)
25.6[3] km/s
HR 6322, SAO 2770, ADS 10242, CCDM 16460+8203[9]
Database references
SIMBADdata

Epsilon Ursae Minoris (ε Ursae Minoris) is a

light years from the Sun. The pair are drawing nearer to the Sun with a radial velocity of −10.57 km/s.[6]

A light curve for Epsilon Ursae Minoris, plotted from TESS data[11]

This system forms a

eclipsing binary. The primary eclipse has a minimum of 4.23 in magnitude, while the secondary minimum is magnitude 4.21.[2] This eclipsing behavior was discovered by German astronomer P. Guthnick using observations between 1946 and 1947.[12]

The primary is an

tidal interaction with the secondary.[13]

Epsilon Ursae Minoris has a visual companion: a magnitude 12.32 star at an

arc seconds along a position angle of 2°, as of 2014.[14]

According to R. H. Allen's Star Names, the stars α, β, γ, δ & ε Ursae Minoris were collectively known as Circitores.[15] This led to the name Circitores specifically for ε Ursae Minoris appearing in a 1971 NASA memorandum listing star names.[16]

References

  1. ^
    S2CID 18759600
    .
  2. ^
    hdl:10995/27061
  3. ^
    S2CID 118450304
    .
  4. ^
    Bibcode:1978A&AS...34....1N
    .
  5. ^
    Bibcode:2006ASPC..348..269R
    .
  6. ^
    S2CID 15290475
    .
  7. doi:10.1086/317850
    .
  8. ^
    S2CID 119387088
    .
  9. ^ "eps UMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-14.{{cite web}}: CS1 maint: postscript (link)
  10. S2CID 14878976
    .
  11. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 20 December 2022.
  12. ^
    Bibcode:1950PDAO....8..401C
    .
  13. Bibcode:2004IAUS..215..144D
  14. ^ Mason, B. D.; et al. (2008), Washington Visual Double Star Catalog, 2006.5 (WDS), U. S. Naval Observatory, Washington D.C., archived from the original on 2011-02-14, retrieved 2017-09-15.
  15. ^ Allen, R.H. (1899), Star Names: Their Lore and Meaning, p. 459
  16. ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
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