Astronomy:Gliese 221
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 53m 00.285s[1] |
| Declination | −05° 59′ 41.44″[1] |
| Apparent magnitude (V) | 9.70[2] |
| Characteristics | |
| Spectral type | K7V/M0V[3] |
| B−V color index | 1.321±0.001[2] |
| Astrometry | |
| Radial velocity (Rv) | +22.9±0.4[1] km/s |
| Proper motion (μ) | RA: −1.170[1] mas/yr Dec.: −346.762[1] mas/yr |
| Parallax (π) | 49.2485 ± 0.0185[1] mas |
| Distance | 66.23 ± 0.02 ly (20.305 ± 0.008 pc) |
| Absolute magnitude (MV) | 8.154±0.077[4] |
| Details | |
| Mass | 0.72±0.21[5] M☉ |
| Radius | 0.613±0.064[4] R☉ |
| Luminosity | 0.095±0.01[5] L☉ |
| Surface gravity (log g) | 4.74±0.02[5] cgs |
| Temperature | 4,324±100[5] K |
| Metallicity [Fe/H] | −0.34±0.08[5] dex |
| Age | 4.4±4[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
Gliese 221 (GJ 221), also known as BD-06 1339, is a star with an exoplanetary companion in the equatorial constellation of Orion. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 9.70[2] and an absolute magnitude of 8.15.[4] Using parallax measurements, the distance to this system can be estimated as 66.2 light-years. It is receding from the Sun with a radial velocity of +23 km/s.[1] This is a high proper motion star, traversing the celestial sphere at an angular rate of 0.333″·yr−1.[7]
This is a late K-type or early M-type main-sequence star with a stellar classification of K7V/M0V.[3] It has 72% of the mass and 61% of the radius of the Sun.[5] The star is roughly 4.4[5] billion years old and is depleted in heavy elements, containing just 46% of solar abundance of iron.[5] It is an active star and the level of chromospheric activity has been found to vary significantly over time.[3] The star is radiating 10%[5] of the luminosity of the Sun from its photosphere at an effective temperature of 4,324 K.[5]
Planetary system
From 2003 to 2012, the star was under observance from the High Accuracy Radial Velocity Planet Searcher (HARPS). It is becoming less active and this reduced activity allowed for lower-mass planetary measurements to be made.
A super-Venus planet, and an eccentric Neptune / Saturn in the habitable zone, were deduced by radial velocity in January 2013.[8] They were confirmed in May 2013.[9] In January 2014, a candidate planet d was proposed.[10]
The planet Gliese 221b (BD-06 1339 b) is not transiting the disk of the parent star,[11] and its existence was disputed in 2022.[12]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (disputed[12]) | >8.5806 ± 1.2712 M⊕ | 0.0428 ± 0.0007 | 3.8728 ± 0.0004 | — | — | — |
| c | >54.026 ± 9.534 M⊕ | 0.435 ± 0.007 | 125.94 ± 0.44 | 0.31 ± 0.11 | — | — |
| d (unconfirmed) | 22.246 M⊕ | 1.0947 | 500 | — | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 Lo Curto, G. et al. (March 2013), "The HARPS search for southern extra-solar planets. XXXII. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone", Astronomy & Astrophysics 551: 7, doi:10.1051/0004-6361/201220415, A59, Bibcode: 2013A&A...551A..59L.
- ↑ 4.0 4.1 4.2 Houdebine, E. R. et al. (2016). "Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/Sin I for a Large Sample of Late-K and M Dwarfs". The Astrophysical Journal 822 (2): 97. doi:10.3847/0004-637X/822/2/97. Bibcode: 2016ApJ...822...97H.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 Sousa, S. G. et al. (2018), "SWEET-Cat updated", Astronomy & Astrophysics 620: A58, doi:10.1051/0004-6361/201833350, Bibcode: 2018A&A...620A..58S.
- ↑ "BD-06 1339". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BD-06+1339.
- ↑ Luyten, W. J. (June 1995), "NLTT Catalogue", VizieR On-line Data Catalog: I/98A. Originally published in: 1979nltt.book.....L, Bibcode: 1995yCat.1098....0L.
- ↑ 8.0 8.1 Lo Curto, G. 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, doi:10.1051/0004-6361/201220415, Bibcode: 2013A&A...551A..59L.
- ↑ Arriagada, Pamela et al. (2013), "Two Planetary Companions Around the K7 Dwarf Gj 221: A Hot Super-Earth and a Candidate in the Sub-Saturn Desert Range", The Astrophysical Journal 771 (1): 42, doi:10.1088/0004-637X/771/1/42, Bibcode: 2013ApJ...771...42A.
- ↑ Tuomi, Mikko (2014), "A new cold sub-Saturnian candidate planet orbiting GJ 221", Monthly Notices of the Royal Astronomical Society: Letters 440: L1–L5, doi:10.1093/mnrasl/slu014
- ↑ Gillon, M. et al. (2017), "The Spitzer search for the transits of HARPS low-mass planets", Astronomy & Astrophysics 601: A117, doi:10.1051/0004-6361/201629270, Bibcode: 2017A&A...601A.117G.
- ↑ 12.0 12.1 Simpson, Emilie R.; Fetherolf, Tara; Kane, Stephen R.; Li, Zhexing; Pepper, Joshua; Močnik, Teo (2022). "Revisiting BD-06 1339b: A Likely False Positive Caused by Stellar Activity". The Astronomical Journal 163 (5): 215. doi:10.3847/1538-3881/ac5d41. Bibcode: 2022AJ....163..215S.
- ↑ "Planet BD-06 1339 c", Extrasolar Planets Encyclopaedia, https://exoplanet.eu/catalog/bd_06_1339_c--1248/.
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