21 Comae Berenices

Last updated
21 Comae Berenices
UUComLightCurve.png
A visual band light curve for UU Comae Berenices from MOST data. Adapted from Paunzen et al. (2019) [1]
Observation data
Epoch J2000.0       Equinox J2000.0 (ICRS)
Constellation Coma Berenices
Right ascension 12h 31m 00.561s [2]
Declination +24° 34′ 01.80″ [2]
Apparent magnitude  (V)5.47 [3] or 5.41 – 5.46 [4]
Characteristics
Evolutionary stage main sequence [1]
Spectral type A3p SrCr [5]
B−V color index 0.056±0.008 [3]
Variable type α2 CVn [1] + δ Sct [4]
Astrometry
Radial velocity (Rv)+1.0±1.8 [3]  km/s
Proper motion (μ)RA: −12.474  mas/yr [2]
Dec.: −9.085  mas/yr [2]
Parallax (π)12.0785 ± 0.1214  mas [2]
Distance 270 ± 3  ly
(82.8 ± 0.8  pc)
Absolute magnitude  (MV)0.66 [3]
Details [1]
Mass 2.29±0.10  M☉
Radius 2.6±0.2  R☉
Luminosity 38.2±1.3  L☉
Surface gravity (log g)3.9±0.2  cgs
Temperature 8,900±200  K
Rotation 2.05219 d
Rotational velocity (v sin i)63±2 km/s
Age 400–800  Myr
Other designations
Kissīn [6] , 21 Com, UU Com, BD+25°2517, HD  108945, HIP  61071, HR  4766, SAO  82346 [7]
Database references
SIMBAD data

21 Comae Berenices is a variable star in the northern constellation of Coma Berenices. [8] It has the variable star designation UU Comae Berenices, while 21 Comae Berenices is the Flamsteed designation. [7] [8] [9]

Contents

About

According to R. H. Allen, English orientalist Thomas Hyde attributed the ancient title Kissīn to this star, a name that comes from a climbing plant – either bindweed or dog rose. [6] This star has a white hue and is just visible to the naked eye with an apparent visual magnitude that fluctuates around 5.47. [3] Based upon parallax measurements, it is located at a distance of approximately 270  light years away from the Sun. [2] It is a single star but is a confirmed physical member of the Melotte 111 open cluster. [10]

History

This object has been studied extensively since 1953, producing some occasionally contradictory results such as hints of pulsational behavior or a binary companion. It is a weakly magnetic chemically peculiar star of type CP2, or Ap star, that is most likely on the main sequence. [1] The stellar classification is A3p SrCr, [5] where the suffix notation indicates abundance anomalies of the iron-peak element chromium, as well as strontium.

This is an Alpha2 Canum Venaticorum (ACV) variable, which indicates it varies in luminosity as it rotates due to spots on its surface created by a magnetic field. The range of variation has an amplitude of 0.02 magnitude and a period of just over two days. [1] Samus et al. (2017) have it classified as a low-amplitude Delta Scuti variable, [4] although this is disputed. [1]

The age of the Melotte 111 cluster, and therefore this star, lies in the range of 400–800 million years. The star has a projected rotational velocity of 63 km/s, with a polar inclination of 64° or greater, resulting in a rotation period of 2.05 days. Stellar evolutionary models yield a mass of around 2.3 times that of the Sun and 2.6 times the Sun's radius for this object. It is radiating 38 times the luminosity of the Sun from its photosphere at an effective temperature of 8,900 K. [1]

Related Research Articles

<span class="mw-page-title-main">63 Andromedae</span> Star in the constellation Andromeda

63 Andromedae is an Alpha2 Canum Venaticorum variable star in the constellation Andromeda. Its variable star designation is PZ Andromedae. With an apparent magnitude of about 5.6, it is bright enough to be seen by naked eye. Based upon an annual parallax shift of 8.53 mas, it is located 382 light years away.

<span class="mw-page-title-main">FK Comae Berenices</span> Star in the constellation of Coma Berenices

FK Comae Berenices is a variable star that varies in apparent magnitude between 8.14 and 8.33 over a period of 2.4 days. It is the prototype for the FK Comae Berenices class of variable stars. The variability of FK Com stars may be caused by large, cool spots on the rotating surfaces of the stars. This star is thought to be the result of a recent binary merger, resulting in a high rate of both spin and magnetic activity.

<span class="mw-page-title-main">OU Andromedae</span> Rotationally variable star in the constellation Andromeda

OU Andromedae is a rotationally variable star in the constellation Andromeda. Varying between magnitudes 5.87 and 5.94, it has been classified as an FK Comae Berenices variable, but the classification is still uncertain. It has a spectral classification of G1IIIe, meaning that it is a giant star that shows emission lines in its spectrum. It is also likely in its horizontal branch phase of evolution.

<span class="mw-page-title-main">BN Camelopardalis</span> Star in the constellation Camelopardalis

BN Camelopardalis is a suspected astrometric binary in the northern circumpolar constellation of Camelopardalis. It appears as a variable star that is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude that fluctuates around 5.49. The system is located at a distance of around 310 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +9 km/s.

Gamma Comae Berenices, Latinized from γ Comae Berenices, is a single, orange-hued star in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 19.50 mas as seen from Earth, its distance can be estimated as around 167 light years from the Sun. The star is moving away from the Sun with a radial velocity of +3 km/s.

<span class="mw-page-title-main">12 Comae Berenices</span> Star in the constellation Coma Berenices

12 Comae Berenices is a binary star system in the northern constellation of Coma Berenices. It is the brightest member of the Coma Star Cluster and is visible to the naked eye with an apparent visual magnitude of 4.80. Although listed as a suspected variable star, there is no photometric evidence of it being variable in luminosity. However, the radial velocity was found to be variable, as announced by W. W. Campbell in 1910. The first orbital solution was published by Vinter Hansen in the 1940s. It is a double-lined spectroscopic binary with an orbital period of 396.5 days and an eccentricity of 0.566.

<span class="mw-page-title-main">37 Comae Berenices</span> Triple-star system in the constellation Coma Berenices

37 Comae Berenices is a variable star system located around 690 light years away from the Sun in the northern constellation of Coma Berenices. It has the variable star designation LU Comae Berenices. 37 Comae Berenices was a later Flamsteed designation of 13 Canum Venaticorum. This object is visible to the naked eye as a faint, yellow-hued star with a baseline apparent visual magnitude of 4.88. It is drifting closer to the Earth with a heliocentric radial velocity of −14 km/s.

31 Comae Berenices is a yellow giant star in the constellation Coma Berenices. Its apparent magnitude is about 4.9 and slightly variable. It is a rare FK Comae Berenices variable, a variable star that spins rapidly and has large starspots on its surface. It is currently in the Hertzsprung gap and its outer envelope has just begun convection. In 1989 it was given as a spectral standard for the class G0IIIp.

16 Comae Berenices is a single star in the northern constellation of Coma Berenices. 16 Comae Berenices is the Flamsteed designation. It is a member of the Coma Star Cluster and is visible to the naked eye with an apparent visual magnitude of 4.96. Based upon an annual parallax shift of 11.7 mas, it is located about 279 light years away.

<span class="mw-page-title-main">28 Monocerotis</span> Star in the constellation Monoceros

28 Monocerotis is a single star in the equatorial constellation of Monoceros. It has an orange-hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.69. The distance to this star is approximately 450 light years based on parallax, and it has an absolute magnitude of −1.00. The star is drifting further away from the Sun with a radial velocity of +26.7 km/s.

<span class="mw-page-title-main">CU Virginis</span> Star in the constellation Virgo

CU Virginis is a single star in the equatorial constellation of Virgo. It has an apparent visual magnitude of 4.99, which is bright enough to be faintly visible to the naked eye. The distance to this star can be estimated from its annual parallax shift of 13.9 mas, yielding a separation of 234 light years.

13 Comae Berenices is a probable binary star system in the northern constellation of Coma Berenices. It has an apparent visual magnitude of 5.17, which is bright enough to be faintly visible to the naked eye. With an annual parallax shift of 12.33 mas, it is located around 260 light years from the Sun. It is member of the nearby Coma Star Cluster.

<span class="mw-page-title-main">DS Crucis</span> Star in the constellation Crux

DS Crucis is a variable star near the open cluster NGC 4755, which is also known as the Kappa Crucis Cluster or Jewel Box Cluster. It is in the constellation Crux.

<span class="mw-page-title-main">DU Crucis</span> Star in the constellation Crux

DU Crucis is a red supergiant and slow irregular variable star in the open cluster NGC 4755, which is also known as the Kappa (κ) Crucis Cluster or Jewel Box Cluster.

<span class="mw-page-title-main">HD 21071</span> Star in the constellation Perseus

HD 21071 is a blue-white hued variable star in the northern constellation of Perseus. Also known as V576 Persei, it is a sixth magnitude star that is dimly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 6.09. The brightness of the star varies with a multiperiodic cycle. The distance to HD 21071, as determined from an annual parallax shift of 6.1 mas, is 535 light years. It is a member of the young Alpha Persei cluster, Melotte 20, and moving is closer to the Earth with a heliocentric radial velocity of −1.5 km/s.

<span class="mw-page-title-main">HD 111395</span> Star in the constellation Coma Berenices

HD 111395 is a single, variable star in the northern constellation of Coma Berenices. It has the variable star designation LW Com, short for LW Comae Berenices; HD 111395 is the Henry Draper Catalogue designation. The star has a yellow hue and is just bright enough to be barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.29. Based upon parallax measurements, it is located at a distance of 55.8 light years from the Sun. The star is drifting closer with a radial velocity of −8.9 km/s. It is a member of the Eta Chamaeleontis stellar kinematic group.

<span class="mw-page-title-main">V1794 Cygni</span> FK Comae Berenices variable in the constellation Cygnus

V1794 Cygni is a single variable star in the northern constellation Cygnus. It has the identifier HD 199178 from the Henry Draper Catalogue; V1794 Cygni is its variable star designation. With an apparent visual magnitude of 7.24, it's too dim to be visible with the naked eye but can be seen with binoculars. V1794 is located at a distance of 367 light-years (113 pc) based on parallax measurements, but is drifting closer to the Sun with a radial velocity of −31 km/s. It lies superimposed over a region of faint nebulosity to the west of the North American Nebula.

<span class="mw-page-title-main">17 Comae Berenices</span> Multiple star system in the constellation Coma Berenices

17 Comae Berenices is a multiple star system in the northern constellation of Coma Berenices. The brighter component, 17 Com A, is a naked eye star with an apparent visual magnitude of 5.2. It has a faint companion of magnitude 6.6, 17 Com B, positioned at an angular separation of 146.4″ along a position angle of 251°, as of 2018. They are located at a distance of approximately 240 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">V1027 Cygni</span> Star in the constellation Cygnus

V1027 Cygni is a luminous yellow supergiant star located in the constellation of Cygnus, about 14,000 light years away. For a time, it was thought that it could be a low-mass post-AGB star, however recent parallax measurements published in Gaia DR3 have shown this to likely not be the case, and instead it is likely a massive yellow supergiant star.

EK Eridani is a single variable star in the equatorial constellation of Eridanus. It has the designation HR 1362 from the Bright Star Catalogue; EK Eridani is the variable star designation, abbreviated EK Eri. This star is dimly visible to the naked eye with a brightness that fluctuates around 6.15. Based on parallax measurements, it is located at a distance of 209 light years from the Sun. The star is drifting further away with a heliocentric radial velocity of 6.9 km/s.

References

  1. 1 2 3 4 5 6 7 8 Paunzen, Ernst; et al. (May 2019), "A revisit to the enigmatic variable star 21 Comae", Monthly Notices of the Royal Astronomical Society, 485 (3): 4247–4259, arXiv: 1904.04809 , Bibcode:2019MNRAS.485.4247P, doi: 10.1093/mnras/stz413 , S2CID   104292433.
  2. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644
  4. 1 2 3 Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869.
  5. 1 2 Renson, P.; Manfroid, J. (2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi: 10.1051/0004-6361/200810788 .
  6. 1 2 Allen, Richard Hinckley (1963), Star Names: Their Lore and Meaning, Dover Publications Inc., p. 171, retrieved 2019-11-01.
  7. 1 2 "21 Com". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-11-01.
  8. 1 2 "21 Comae Berenices - Star in Coma Berenices | TheSkyLive.com". theskylive.com. Retrieved 2023-06-13.
  9. ↑ Guide, Universe (25 January 2015). "21 Comae Berenices Star Facts". Universe Guide. Retrieved 13 June 2023.
  10. ↑ Silaj, J.; Landstreet, J. D. (2014), "Accurate age determinations of several nearby open clusters containing magnetic Ap stars", Astronomy & Astrophysics, 566: A132, arXiv: 1407.4531 , Bibcode:2014A&A...566A.132S, doi:10.1051/0004-6361/201321468, S2CID   53370832.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.