Gliese 221
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 53m 00.0s |
| Declination | −05° 59′ 41″ |
| Apparent magnitude (V) | 9.69 ± 0.01 |
| Characteristics | |
| Spectral type | K7V/M0V |
| Astrometry | |
| Proper motion (μ) | RA: −1.045±0.070[1] mas/yr Dec.: −346.721±0.070[1] mas/yr |
| Parallax (π) | 49.3062 ± 0.0529[1] mas |
| Distance | 66.15 ± 0.07 ly (20.28 ± 0.02 pc) |
| Details | |
| Mass | 0.7 M☉ |
| Radius | ? R☉ |
| Luminosity | 0.095 ± 0.01 L☉ |
| Surface gravity (log g) | 4.74 ± 0.02 cgs |
| Temperature | 4324 ± 100 K |
| Metallicity | -0.14 ± 0.17 |
| Age | 4.4 ± 4 × 109 years |
| Other designations | |
BD-061339, HIP 27803, LTT 2396 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
Gliese 221 is an orange-red dwarf star.
Planetary system
From 2003 to 2012, the star was under observance from HARPS. It is becoming less active and this reduced activity allowed for lower-mass planetary measurements to be made.
In 2012, a super-Venus planet, and an eccentric Neptune / Saturn in the habitable zone,[2] were deduced by radial velocity. They were published in January 2013. In January 2014, a new, sub-Saturn planet candidate was reported.[3]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.027 ± 0.004 MJ | 0.0428 ± 0.0007 | 3.8728 ± 0.0004 | - | — | — |
| c | >0.17 ± 0.03 MJ | 0.435 ± 0.007 | 125.94 ± 0.44 | 0.31 ± 0.11 | — | — |
| d (unconfirmed) | >0.07 MJ | 1.0947 | 500 | — | — | — |
References
- 1 2 3 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.
- ↑ The preprint defined the star's HZ to 0.5-0.9 AU. Square root of luminosity would put an Earth analogue at 0.31 AU. The planet's semimajor is 0.435 AU.
- ↑ A new cold sub-Saturnian candidate planet orbiting GJ 221: Mikko Tuomi, January 16, 2014
- ↑ "Planet BD-061339b".
- ↑ G. Lo Curto; et al. (2013). "The HARPS search for southern extrasolar planets: XXXVI. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone". Astronomy & Astrophysics. 551: A59. arXiv:1301.2741. Bibcode:2013A&A...551A..59L. doi:10.1051/0004-6361/201220415.
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