30 Arietis (abbreviated 30 Ari) is a 6th-apparent-magnitude multiple star system[4] in the constellation of Aries. 30 Arietis is the Flamsteed designation. 30 Arietis A and B are separated by 38.1″ or about 1,500 AU at a distance of 130 light years away. The main components of both systems are both binaries with a composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores. The 30 Arietis system is 910 million years old, one fifth the age of the Sun.
 30 Arietis star system hierarchy | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aries |
| 30 Arietis A | |
| Right ascension | 02h 37m 00.5235s[1] |
| Declination | +24° 38′ 49.9880″[1] |
| 30 Arietis B | |
| Right ascension | 02h 36m 57.7449s[2] |
| Declination | +24° 38′ 53.0026″[2] |
| Characteristics | |
| Spectral type | F5 V / F6 V[3] |
| B−V color index | 0.410 / 0.510[3] |
| Astrometry | |
| 30 Arietis A | |
| Proper motion (μ) | RA: 136.862±0.137[1] mas/yr Dec.: −15.188±0.141[1] mas/yr |
| Parallax (π) | 22.1261 ± 0.0726 mas[1] |
| Distance | 147.4 ± 0.5 ly (45.2 ± 0.1 pc) |
| 30 Arietis B | |
| Proper motion (μ) | RA: 141.411±0.083[2] mas/yr Dec.: −10.677±0.086[2] mas/yr |
| Parallax (π) | 22.3641 ± 0.0516 mas[2] |
| Distance | 145.8 ± 0.3 ly (44.7 ± 0.1 pc) |
| Orbit[4][5] | |
| Primary | 30 Arietis A |
| Companion | 30 Arietis BC |
| Period (P) | 34000 yr |
| Semi-major axis (a) | 40" (1670 AU) |
| Orbit[5] | |
| Primary | 30 Arietis B |
| Companion | 30 Arietis C |
| Period (P) | 80 yr |
| Semi-major axis (a) | 22.3 AU |
| Orbit[5] | |
| Primary | 30 Arietis B |
| Companion | 30 Arietis Bb |
| Period (P) | 335.1 ± 2.5 d (0.917 ± 0.007 yr) |
| Semi-major axis (a) | 0.995 ± 0.012 AU |
| Eccentricity (e) | 0.289 ± 0.092 |
| Inclination (i) | 4.14+0.96 −0.90°[6]° |
| Details | |
| 30 Arietis A | |
| Mass | 1.31 ± 0.04[3] M☉ |
| Radius | 1.37 ± 0.03[3] R☉ |
| Age | 860±630[5] Myr |
| 30 Arietis Ba | |
| Mass | 1.16 ± 0.04[3] M☉ |
| Radius | 1.13 ± 0.03[3] R☉ |
| Age | 910±830[5] Myr |
| Details | |
| 30 Arietis Bb | |
| Mass | 147+41 −29[6] MJup |
| Other designations | |
| Database references | |
| SIMBAD | A |
| B | |
| Exoplanet Archive | data |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
Star system
edit30 Arietis A and B are separated by 38.1", corresponding to 1,500 AU at a distance of 130 light years. The pair are at almost the same distance, have very similar proper motions, and are considered almost certain to be gravitationally bound with a likely period around 34,000 years.[5] The main components of both systems are both binaries with a composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores.[3]
30 Arietis A is a spectroscopic binary with an orbital period of 1.1 days.[7] The primary Aa is an F-type main sequence star about 31% more massive than the Sun, while the companion Ab is a faint red dwarf only about 15% the mass of the Sun.
30 Arietis B has been reported to have a red dwarf companion at a distance of 22 AU[5] and another red dwarf Bb at about 1 AU.[3] In 2020, after the inclination of the planetary orbit was measured, the "planet" was found to fall in the mass range of a brown or red dwarf.[6] The more distant companion was referred to as C to distinguish it from Bb, and at about 0.5" it has been imaged using adaptive optics.[5]
30 Arietis Bb
edit30 Arietis Bb (sometimes abbreviated 30 Ari Bb) is a red dwarf which orbits the F-type main sequence star 30 Arietis Ba, located in a quintuple star system approximately 146 light years away in the constellation Aries. The red dwarf, initially believed to be a massive planet or brown dwarf, was announced in a paper published online on September 24, 2009. It was discovered by using precision radial velocity measurements from the echelle spectrograph installed on the Alfred-Jensch telescope in Karl Schwarzschild Observatory.[3] The star had a minimum mass of nearly 10 times that of Jupiter.[8] In 2020, after the inclination of the planetary orbit was measured to be just 4.14+0.96
−0.90°, the "planet" was found to fall in the mass range of red dwarf stars.[6]
See also
editReferences
edit- ^ a b c d e 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.
- ^ a b c d e 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.
- ^ a b c d e f g h i Guenther, E. W.; et al. (2009). "A substellar component orbiting the F-star 30 Arietis B". Astronomy and Astrophysics. 507 (3): 1659–1665. arXiv:0912.4619. Bibcode:2009A&A...507.1659G. doi:10.1051/0004-6361/200912112. S2CID 55685116.
- ^ a b Whitney Clavin (2015). "Planet 'Reared' by Four Parent Stars". NASA. Retrieved 4 March 2015.
- ^ a b c d e f g h Roberts Jr, Lewis C.; Tokovinin, Andrei; Mason, Brian D.; Riddle, Reed L.; Hartkopf, William I.; Law, Nicholas M.; Baranec, Christoph (2015). "Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars". The Astronomical Journal. 149 (4): 118. arXiv:1503.01211. Bibcode:2015AJ....149..118R. doi:10.1088/0004-6256/149/4/118. S2CID 30908636.
- ^ a b c d Kiefer, F.; et al. (January 2021). "Determining the true mass of radial-velocity exoplanets with Gaia. Nine planet candidates in the brown dwarf or stellar regime and 27 confirmed planets". Astronomy & Astrophysics. 645 A7. arXiv:2009.14164. Bibcode:2021A&A...645A...7K. doi:10.1051/0004-6361/202039168. S2CID 221995447.
- ^ Morbey, C. L.; Brosterhus, E. B. (1974). "A Search for Spectroscopic Binaries from Published Radial Velocity Data". Publications of the Astronomical Society of the Pacific. 86 (512): 455. Bibcode:1974PASP...86..455M. doi:10.1086/129630. JSTOR 40675565.
- ^ Jean Schneider (2011). "Notes for Planet 30 Ari B b". Extrasolar Planets Encyclopaedia. Retrieved 3 October 2011.
External links
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