![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/3/31/V616MonLightCurve.png/640px-V616MonLightCurve.png&w=640&q=50)
A0620-00
Binary star in the constellation Monoceros / From Wikipedia, the free encyclopedia
A0620-00 (abbreviated from 1A 0620-00) is a binary star system in the constellation of Monoceros, with an apparent magnitude of 11.2.
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Monoceros |
Right ascension | 06h 22m 44.542s[2] |
Declination | −00° 20′ 44.29″[2] |
Apparent magnitude (V) | 11.2[3] |
Characteristics | |
Evolutionary stage | Black hole + main sequence[4] |
Spectral type | K2 V[5] |
Variable type | X-ray nova, Ellipsoidal[6] |
Astrometry | |
Radial velocity (Rv) | −5±12[7] km/s |
Proper motion (μ) | RA: −0.439 mas/yr[2] Dec.: −5.138 mas/yr[2] |
Parallax (π) | 0.6969 ± 0.1168 mas[2] |
Distance | approx. 4,700 ly (approx. 1,400 pc) |
Orbit | |
Period (P) | 7.75234 ± 0.00010[7] hr |
Inclination (i) | 50.98 ± 0.87[4]° |
Periastron epoch (T) | JD 2446082.7481 ± 0.0008[7] |
Semi-amplitude (K1) (primary) | 457 ± 8[7] km/s |
Details | |
Black hole | |
Mass | 5.86±1.24[8] M☉ |
Star | |
Mass | 0.34±0.03[8] M☉ |
Radius | 1.057[9] R☉ |
Luminosity | 0.44[9] L☉ |
Surface gravity (log g) | 5.0[5] cgs |
Temperature | 5,000[5] K |
Metallicity [Fe/H] | 0.0[5] dex |
Rotational velocity (v sin i) | 83.8±1.9[5] km/s |
Other designations | |
Database references | |
SIMBAD | data |
A0620-00 consists of two objects. The first object is a K-type main-sequence star.[4][5] The second object cannot be seen, but based on its calculated mass of about 6 M☉,[8][4] it is too massive to be a neutron star and must therefore be a stellar-mass black hole.[7] The two objects orbit each other every 7.75 hours.[7] At a distance of roughly 3,300 light-years (1,000 parsecs) away, the black hole of A0620-00 would be one of the nearest known black holes to the Solar System, closer than GRO J1655-40.[10]
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d2/V616mon_sdss_ugiz_1_besk.jpg/640px-V616mon_sdss_ugiz_1_besk.jpg)
A0620-00 has undergone two X-ray outbreaks. The first one was in 1917.[11] The second burst, in 1975, was detected by the Ariel 5 satellite.[12] During that time, A0620-00 was the brightest X-ray point source.[7] It is now classified as an X-ray nova.[7] Its black hole nature was determined in 1986.[7]
The black hole in A0620-00 pulls matter from the K-type star into an accretion disk.[4] The accretion disk emits significant amounts of visible light and X-rays. Because the K-type star has been pulled into an ellipsoidal shape, the amount of surface area visible, and thus the apparent brightness, changes from the Earth's perspective. A0620-00 also bears the variable star designation V616 Monocerotis.[6]