From Wikipedia, the free encyclopedia
Star in the constellation Virgo
EQ Virginis is a single
[10]
variable star in the
equatorial
constellation of
Virgo . It has a baseline
visual apparent magnitude of 9.36,
[3] but is a
flare star that undergoes sporadic bursts of brightening. The star is located at a distance of 67
light-years from the
Sun based on
parallax measurements, but is drifting closer with a
radial velocity of −23 km/s.
[2] It is a member of the
IC 2391
moving group
[11] of stars, which is between 30 and 50 million years old.
[8]
This is an orange-hued
K-type main-sequence star with a
stellar classification of K5Ve,
[3] where the 'e' suffix indicates
emission lines in the
spectrum . It is a young, rapidly rotating star with a mean
magnetic field strength of 2,500± 300
G .
[12] The star is classified as an
eruptive variable of the
UV Ceti type and a
BY Draconis variable .
[4] It shows strong
chromospheric activity with extensive
star spots that, on average, cover ~24% of the surface.
[7] The star displays a strong
X-ray emission.
[12]
References
^
"MAST: Barbara A. Mikulski Archive for Space Telescopes" . Space Telescope Science Institute. Retrieved 8 December 2021 .
^
a
b
c
d
e
f
g
h
Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018).
"Gaia Data Release 2: Summary of the contents and survey properties" .
Astronomy & Astrophysics . 616 . A1.
arXiv :
1804.09365 .
Bibcode :
2018A&A...616A...1G .
doi :
10.1051/0004-6361/201833051 .
Gaia DR2 record for this source at
VizieR .
^
a
b
c
d Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series , 71 : 245,
Bibcode :
1989ApJS...71..245K ,
doi :
10.1086/191373 ,
S2CID
123149047 .
^
a
b Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports . GCVS 5.1. 61 (1): 80–88.
Bibcode :
2017ARep...61...80S .
doi :
10.1134/S1063772917010085 .
S2CID
255195566 .
^ Luck, R. Earle (March 2018).
"Abundances in the Local Region. III. Southern F, G, and K Dwarfs" . The Astronomical Journal . 155 (3): 31.
Bibcode :
2018AJ....155..111L .
doi :
10.3847/1538-3881/aaa9b5 .
S2CID
125765376 . 111.
^
a
b Casagrande, L.; et al. (2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey". Astronomy & Astrophysics . 530 (A138): 21.
arXiv :
1103.4651 .
Bibcode :
2011A&A...530A.138C .
doi :
10.1051/0004-6361/201016276 .
S2CID
56118016 .
^
a
b
c
d Morris, Brett M.; et al. (September 2019).
"Stellar Properties of Active G and K Stars: Exploring the Connection between Starspots and Chromospheric Activity" . The Astronomical Journal . 158 (3): 16.
arXiv :
1907.00423 .
Bibcode :
2019AJ....158..101M .
doi :
10.3847/1538-3881/ab2e04 .
S2CID
195767281 . 101.
^
a
b Paulson, Diane B.; Yelda, Sylvana; Allen, Peter R.; Kilkenny, David; Liebert, James; Hawley, Suzanne L.; Fraser, Oliver J.; Covey, Kevin R.; Lowrance, Patrick; Kirkpatrick, J. Davy; Burgasser, Adam J. (2006). "Differential Radial Velocities and Stellar Parameters of Nearby Young Stars". The Publications of the Astronomical Society of the Pacific . 118 (843): 706–715.
arXiv :
astro-ph/0605433 .
Bibcode :
2006PASP..118..706P .
doi :
10.1086/504115 .
S2CID
16194615 .
^
"HD 118100" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2021-11-15 .
^ Halbwachs, J. -L; et al. (2018). "Multiplicity among solar-type stars. IV. The CORAVEL radial velocities and the spectroscopic orbits of nearby K dwarfs". Astronomy and Astrophysics . 619 : A81.
arXiv :
1808.04605 .
Bibcode :
2018A&A...619A..81H .
doi :
10.1051/0004-6361/201833377 .
S2CID
119437322 .
^ Montes, D.; et al. (2001). "Late-type members of young stellar kinematic groups - I. Single stars". Monthly Notices of the Royal Astronomical Society . 328 (1): 45–63.
arXiv :
astro-ph/0106537 .
Bibcode :
2001MNRAS.328...45M .
doi :
10.1046/j.1365-8711.2001.04781.x .
S2CID
55727428 .
^
a
b Saar, S. H.; et al. (March 1986). "The Magnetic Field of the BY Draconis Flare Star EQ Virginis". Astrophysical Journal . 302 : 777.
Bibcode :
1986ApJ...302..777S .
doi :
10.1086/164040 .