84 Ursae Majoris

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84 Ursae Majoris

A light curve for CR Ursae Majoris, plotted from TESS data.[1]
Observation data
J2000.0
Constellation
Ursa Major
Right ascension 13h 46m 35.65679s[2]
Declination +54° 25′ 57.6436″[2]
Apparent magnitude (V) 5.65 - 5.70[3]
Characteristics
Spectral type B9pe[4]
B−V color index -0.04[4]
Variable type α2 CVn[3]
Distance
304 ± 1 ly
(93.1 ± 0.4 pc)
Absolute magnitude (MV)0.98±0.12[6]
Details
Primary
Gyr
HIP 67231, HD 120198, HR 5187, SAO 28885[10]
Database references
SIMBADdata

84 Ursae Majoris, also known as HD 120198, is a star about 300

Ursa Major.[2] It is a 5th magnitude star, making it faintly visible to the naked eye of an observer far from city lights. It is an Ap star with an 1,100 gauss magnetic field,[7] and an α2 CVn variable star, varying in brightness from magnitude 5.65 to 5.70, over a period of 1.37996 days.[3] 84 Ursae Majoris is located just 70 arcseconds from the star LDS 2914, but that star is believed to be a background star not physically associated with 84 Ursae Majoris.[11]

Gerhard Jackisch discovered that 84 Ursae Majoris is a variable star, with a period greater than one day, in 1972.

variable star designation CR Ursae Majoris in 1974.[13]

In 1994 John Rice and William Wehlau used Doppler imaging to map the distribution of iron and chromium on the surface of 84 Ursae Majoris. They found that the distribution of those elements across the surface was similar, and the abundances of those elements varied by a factor of 15 across the surface. Chromium was found to be about 600 times more abundant than on the Sun in the regions of the 84 Ursae Majoris surface with the minimum chromium abundance.[14]

The size of 84 Ursae Majoris was measured in red light during 2015 and 2016, using the CHARA array. The limb darkened angular diameter was 0.226±0.008 milliarcseconds.[4]

References

  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 16 January 2023.
  2. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  3. ^
    S2CID 125853869
    .
  4. ^
    S2CID 225158717
    . Retrieved 20 January 2023.
  5. S2CID 119231169
    . Retrieved 20 January 2023.
  6. S2CID 18596834
    . Retrieved 20 January 2023.
  7. ^
    S2CID 233289688
    . Retrieved 20 January 2023.
  8. Bibcode:2000A&A...355..308A
    . Retrieved 20 January 2023.
  9. doi:10.1093/mnras/sty3105
    . Retrieved 20 January 2023.
  10. ^ "84 UMa -- alpha2 CVn Variable". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-01-20.
  11. S2CID 10416471
    . Retrieved 20 January 2023.
  12. doi:10.1002/asna.19722940102
    . Retrieved 20 January 2023.
  13. Bibcode:1975IBVS..961....1K
    . Retrieved 20 January 2023.
  14. S2CID 119432777
    . Retrieved 20 January 2023.
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