30 Arietis

30 Arietis
Location of 30 Arietis (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Aries
30 Arietis A
Right ascension 02h 37m 00.5235s
Declination +24° 38′ 49.990″
Apparent magnitude (V) 6.50
30 Arietis B
Right ascension 02h 36m 57.7454s
Declination +24° 38′ 53.000″
Apparent magnitude (V) 7.09
Characteristics
Spectral type F5 V / F6 V
B−V color index 0.410 / 0.510
Astrometry
30 Arietis A
Radial velocity (Rv)+24.71±7.77 km/s
Proper motion (μ) RA: +136.866 mas/yr
Dec.: −15.349 mas/yr
Parallax (π)22.2608±0.0309 mas
Distance146.5 ± 0.2 ly
(44.92 ± 0.06 pc)
30 Arietis B
Radial velocity (Rv)+12.38±0.31 km/s
Proper motion (μ) RA: +140.951 mas/yr
Dec.: −10.536 mas/yr
Parallax (π)22.5107±0.0315 mas
Distance144.9 ± 0.2 ly
(44.42 ± 0.06 pc)
Orbit
Primary30 Arietis A
Secondary30 Arietis BC
Period (P)34000 yr
Semi-major axis (a)40"
(1670 AU)
Orbit
Primary30 Arietis B
Secondary30 Arietis C
Period (P)80 yr
Semi-major axis (a)22.3 AU
Orbit
Primary30 Arietis B
Secondary30 Arietis Bb
Period (P)339.7+0.3
−0.2 d
(0.930±0.001 yr)
Semi-major axis (a)1.05±0.01 AU
Eccentricity (e)0.45±0.04
Inclination (i)2.9±0.3°
Longitude of the node (Ω)39.0+6.4
−6.3°
Periastron epoch (T)2458000.5+13.6
−16.0 BJD
Argument of periastron (ω)
(secondary)		354+8
−9°
Semi-amplitude (K1)
(primary)		281+27
−25 km/s
Details
30 Arietis A
Mass1.31 ± 0.04 M☉
Radius1.37 ± 0.03 R☉
Age860±630 Myr
30 Arietis Ba
Mass1.16 ± 0.04 M☉
Radius1.13 ± 0.03 R☉
Age910±830 Myr
30 Arietis Bb
Mass188.1+19.7
−18.5 MJup
Other designations
CCDM 02370+2439, WDS 02370+2439
30 Arietis A: BD+24°376, HD 16246, HIP 12189, HR 765, SAO 75471
30 Arietis B: BD+24°375, HD 16232, HIP 12184, HR 764, SAO 75470
Database references
SIMBADA
B
Exoplanet Archivedata

30 Arietis (abbreviated 30 Ari) is a 6th-apparent-magnitude multiple star system in the constellation of Aries. 30 Arietis is the Flamsteed designation. 30 Arietis A and B are separated by 38.1″, or about 1,700 AU at a distance of 145 light-years away. The main components of both systems are both binaries with composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores. 30 Arietis B also has a second stellar companion, making a total of five stars. The 30 Arietis system is 910 million years old, one fifth the age of the Sun.

Star system

30 Arietis star system hierarchy

30 Arietis A and B are separated by 38.1", corresponding to 1,700 AU at a distance of 145 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. The main components of both systems are both binaries with composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores.

30 Arietis A is a spectroscopic binary with an orbital period of 1.1 days. 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 C at a distance of 22 AU, and another companion Bb at about 1 AU. 30 Arietis Bb has a minimum mass consistent with a giant planet, but in 2020, after the orbital inclination was measured, the "planet" was found to fall in the mass range of a red dwarf star. The more distant companion is referred to as C to distinguish it from Bb, and at about 0.5" it has been imaged using adaptive optics.

30 Arietis Bb

30 Arietis Bb (sometimes abbreviated 30 Ari Bb) is a red dwarf which orbits the F-type main sequence star 30 Arietis Ba. 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. The object has a minimum mass of nearly 10 times that of Jupiter. 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.

See also

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 Hauck, B.; Mermilliod, M. (1998). "Uvbybeta photoelectric photometric catalogue". Astronomy and Astrophysics Supplement Series. 129 (3): 431. Bibcode:1998A&AS..129..431H. doi:10.1051/aas:1998195.
  3. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 4 5 6 7 8 9 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.
  5. 1 2 Whitney Clavin (2015). "Planet 'Reared' by Four Parent Stars". NASA. Archived from the original on 4 March 2016. Retrieved 4 March 2015.
  6. 1 2 3 4 5 6 7 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.
  7. 1 2 Piccinini, G.; Petralia, A.; et al. (January 2026). "True Masses using RV data with Hipparcos and Gaia Astrometry". Astronomy & Astrophysics. arXiv:2601.09401.
  8. ↑ 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.
  9. 1 2 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.
  10. ↑ Jean Schneider (2011). "Notes for Planet 30 Ari B b". Extrasolar Planets Encyclopaedia. Retrieved 3 October 2011.