Gliese 569
Nearby red dwarf in the constellation Boötes
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Gliese 569 is a star in the constellation Boötes. It is orbited by a pair of brown dwarfs. The system lies 32.45 light years away.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Boötes |
| Gliese 569 A | |
| Right ascension | 14h 54m 29.2362s[2] |
| Declination | +16° 06′ 03.798″[2] |
| Apparent magnitude (V) | 10.15[3] |
| Gliese 569 B | |
| Right ascension | 14h 54m 29.7686s[4] |
| Declination | +16° 06′ 05.627″[4] |
| Characteristics | |
| Gliese 569 A | |
| Evolutionary stage | main-sequence star |
| Spectral type | M3 |
| Apparent magnitude (g) | 9.12[2] |
| Variable type | Flare star[5] |
| Gliese 569 B | |
| Spectral type | M8.5+M9[6] |
| Apparent magnitude (g) | 15.32[4] |
| Astrometry | |
| Gliese 569 A | |
| Radial velocity (Rv) | −8.00±0.17 km/s |
| Proper motion (μ) | RA: +279.12±0.02 mas/yr[2] Dec.: −117.91±0.02 mas/yr[2] |
| Parallax (π) | 100.5243±0.0210 mas[2] |
| Distance | 32.446 ± 0.007 ly (9.948 ± 0.002 pc) |
| Orbit[7] | |
| Primary | Gliese 569 Ba |
| Name | Gliese 569 Bb |
| Period (P) | 870±9 days |
| Semi-major axis (a) | (90.1±0.7)×10−3" (0.89±0.02[8] AU) |
| Eccentricity (e) | 0.317±0.010 |
| Inclination (i) | 30.0±1.6° |
| Longitude of the node (Ω) | 313±4° |
| Periastron epoch (T) | 2010.263±0.012 |
| Argument of periastron (ω) (secondary) | 262.5±2.2° |
| Details | |
| Gliese 569 A | |
| Mass | 0.48[9] M☉ |
| Radius | 0.43[9] R☉ |
| Luminosity | 0.034±0.008[10] L☉ |
| Temperature | 3,649±79[10] K |
| Rotation | 14.7[9] days |
| Age | <700[6] Myr |
| Gliese 569 Ba | |
| Mass | 0.081±0.010[7] M☉ |
| Radius | 0.119±0.020[11] R☉ |
| Luminosity | 4.5+0.8 −0.7×10−4[11] L☉ |
| Surface gravity (log g) | 4.5[11] cgs |
| Temperature | 2,440±100[11] K |
| Rotational velocity (v sin i) | 19[6] km/s |
| Age | <700[6] Myr |
| Gliese 569 Bb | |
| Mass | 0.059±0.007[7] M☉ |
| Radius | 0.102±0.020[11] R☉ |
| Luminosity | 2.6+0.5 −0.4×10−4[11] L☉ |
| Surface gravity (log g) | 4.5[11] cgs |
| Temperature | 2,305±100[11] K |
| Rotational velocity (v sin i) | 6[6] km/s |
| Age | <700[6] Myr |
| Other designations | |
| Gliese 569, BD+16 2708, G 136-28, GSC 01478-00495, HIP 72944, 2MASS J14542923+1606039, TYC 1478-495-1, CE Boötis, WDS J14545+1606[12] | |
| Database references | |
| SIMBAD | Gliese 569 A |
| Gliese 569 B | |
System
The primary star GJ 569A is orbited by the much fainter (3.7 magnitudes) secondary GJ 659B at a projected separation of 5.92 arcseconds, discovered in 1988.[13] The star GJ 569B (BD+16 2708B) itself is a close binary system of two high-mass brown dwarfs in a 2.4-year orbit,[14] and a small (0.538±0.048) magnitude difference between components.[15] The orbital plane of close binary GJ 569Ba and GJ 569Bb is expected to precess at timescales of about 100 thousand years due to the gravitational influence of GJ 569A.[6]
Properties
The primary star Gliese 569A is a flare star.[1] The star was given its variable star designation, CE Boötis, in 1975.[16] The nature of the brown dwarf binary Gliese 569B is highly uncertain, and it was even suspected Gliese 569Ba itself may be either a low-mass star or a binary object. But with a mass about 8–9% that of the Sun means it may possibly be a binary of two extremely low mass ultra-cool dwarf stars that are extremely dim, dim enough to look like a brown dwarf.[8] Both brown dwarfs are weakly variable, likely due to starspot activity.[14]