HD 222582
Multiple star system in the constellation Aquarius
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HD 222582 is a multiple star system in the equatorial constellation of Aquarius. It is invisible to the naked eye with an apparent visual magnitude of 7.7,[3] but can be viewed with binoculars or a small telescope.[13] The system is located at a distance of 137 light years from the Sun based on parallax,[2] and it is drifting further away with a radial velocity of +12 km/s.[7] It is located close enough to the ecliptic that it is subject to lunar occultations.[14]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius[1] |
| Right ascension | 23h 41m 51.5301s[2] |
| Declination | −05° 59′ 08.729″[2] |
| Apparent magnitude (V) | 7.685±0.005[3] |
| Characteristics | |
| HD 222582A | |
| Evolutionary stage | Main sequence |
| Spectral type | G5V[4] |
| B−V color index | 0.648±0.002[5] |
| HD 222582B | |
| Spectral type | M4.5V[6] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +12.020±0.0004[7] km/s |
| Proper motion (μ) | RA: −145.492(29) mas/yr[2] Dec.: −111.458(21) mas/yr[2] |
| Parallax (π) | 23.7955±0.0238 mas[2] |
| Distance | 137.1 ± 0.1 ly (42.02 ± 0.04 pc) |
| Absolute magnitude (MV) | 4.44±0.12[3] |
| Position (relative to HD 222582A)[6] | |
| Component | HD 222582B |
| Epoch of observation | 2018 |
| Angular distance | 109.56±0.18″ |
| Position angle | 299.52±0.03° |
| Projected separation | 4637±59 AU AU |
| Details | |
| A | |
| Mass | 0.993±0.035[8] M☉ |
| Radius | 1.137±0.017[8] R☉ |
| Luminosity | 1.302+0.005 −0.004[9] L☉ |
| Surface gravity (log g) | 4.370±0.009[5] cgs |
| Temperature | 5,790±3[5] K |
| Metallicity [Fe/H] | −0.005±0.003[5] dex |
| Rotational velocity (v sin i) | 1.74±0.12[10] km/s |
| Age | 6.7±0.3[5] Gyr |
| Ba+Bb | |
| Mass | 0.2[11] M☉ |
| Other designations | |
| BD−06°6262, GC 32912, HD 222582, HIP 116906, SAO 146849, WDS J23419-0559A, NLTT 57682, 2MASS J23415154-0559086[12] | |
| Database references | |
| SIMBAD | data |
| Planet | |
| HD 222582 b | Data Simbad |
| Data ExoPlanet | |
Star system
The primary member of this system, designated component A, is an ordinary G-type main-sequence star with a stellar classification of G5V.[4] The physical properties of the star are similar enough to the Sun that it is considered a candidate solar twin.[15][5] It is about 6.5[10] billion years old with an inactive chromosphere[15] and is spinning with a low projected rotational velocity of 1.7 km/s.[10] The mass[8] and metallicity[5] of this star are essentially the same as the Sun. It has a 14% larger radius and is radiating 1.3 times the luminosity of the Sun from its photosphere at an effective temperature of 5,790 K.[5]
Component B of this system is a close binary[16][17] system with the components designated HD 222582 Ba and Bb. The pair have a combined class of M4.5 V+[6] and about 20% the mass of the Sun.[11]
Planetary system
In November 1999, a dense superjovian planet was announced orbiting the primary by the California and Carnegie Planet Search. Designated component 'b', it was discovered using the radial velocity method, using 24 observations over a period of 1.5 years. The exoplanet is orbiting with a period of 1.57 years and a very large eccentricity of 0.76, ranging in distance from 0.39 AU out to 2.31 AU away from the primary.[18][19]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 8.37[20] MJ | 1.35 | 572 | 0.76 | — | — |