EV Lacertae

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Star
EV Lacertae
Artist's impression of the EV Lacertae flare
Artist's impression of the EV Lacertae flare
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation lizard
Right ascension 22 h 46 m 49.73 s
declination + 44 ° 20 ′ 2.4 ″
Apparent brightness 10.29 mag
Typing
B − V color index +1.59 
Spectral class M4.5 Ve
Variable star type UV + BY 
Astrometry
Radial velocity (0.40 ± 0.11) km / s
parallax (198.01 ± 0.04)  mas
distance (16.46 ± 0.01)  ly
(5.05 ± 0.01)  pc
Visual absolute brightness M vis +11.7 mag
Proper movement 
Rec. Share: (−706.15 ± 0.07)  mas / a
Dec. portion: (−458.78 ± 0.06)  mas / a
Physical Properties
Dimensions (0.328 ± 0.007)  M ☉
radius (0.337 ± 0.010)  R ☉
Age 300 mill.  A
Other names
and catalog entries
Bonn survey BD + 43 ° 4305
Gliese catalog FY 873 [1]
Hipparcos catalog HIP 112460 [2]
Tycho catalog TYC 3226-2288-1 [3]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J22464980 + 4420030 [4]
Other names EV Lacertae • LHS 3853
annotation
  1. ↑ Calculated from apparent brightness and distance.

EV Lacertae (short EV Lac ), other name Gliese 873 , is a variable star in the constellation Lizard (lat. Lacerta ).

It is a red dwarf , whose mass corresponds to about a third of the mass of our sun and which is only one percent of its brightness. EV Lacertae is 16  light years from Earth and, with an estimated age of 300 million years, is still a young star that has been noticed by radiation eruptions for a long time . These are indirectly the result of its young age, as it still rotates quickly and the magnetic field on the surface is strongly twisted . The radiation eruptions occur when the energy stored in the magnetic field is suddenly released during a short circuit ( reconnection ) of the magnetic field lines .

The star became famous through a huge radiation eruption on April 25, 2008, the strong X-ray and gamma radiation of which was registered by the two satellite telescopes Wind and Swift . It was the strongest burst of radiation that has ever been observed in a normal star. So far, astronomers have only known similar eruptions from neutron stars .

Individual evidence

  1. ↑ a b c d e EV Lac. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on February 23, 2019 .
  2. ^ Hipparcos catalog (ESA 1997)
  3. ↑ a b EV Lac. In: VSX. AAVSO , accessed February 23, 2019 .
  4. ↑ a b P. E. Kervella, F. Arenou, F. Mignard, F. Thévenin: Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly . In: Astronomy & Astrophysics . 623, p. A72. arxiv : 1811.08902 . bibcode : 2019A & A ... 623A..72K . doi : 10.1051 / 0004-6361 / 201834371 .
  5. ↑ ev-lacertae
  6. ^ A flare on EV Lacertae
  7. ↑ Small star with a large flare
  8. ↑ NASA - Pipsqueak Star Unleashes Monster Flare