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  • 21 Aug, 2019

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Rho Coronae Borealis
Rho Coronae Borealis (ρ CrB, ρ Coronae Borealis) is a yellow dwarf star 57.1 light-years (17.5 parsecs) away in the constellation of Corona Borealis. The star is thought to be similar to the Sun with nearly the same mass, radius, and luminosity. It is orbited by four known exoplanets.

Stellar properties

Rho Coronae Borealis is a yellow main-sequence star of the spectral type G0V. The star is thought to have 96 percent of the Sun's mass, along with 1.3 times its radius and 1.7 times its luminosity. It may only be 51 to 65 percent as enriched with elements heavier than hydrogen (based on its abundance of iron) and is likely somewhat older than the Sun at around ten billion years old.

The rotation period of Rho Coronae Borealis is approximately 20 days, even though at this age stars are hypothesized to decouple their rotational evolution and magnetic activity.

Multiple star catalogs list a 10th-magnitude companion about two arc-minutes away, but it is an unrelated background object.

Planetary system

An extrasolar planet in a 39.8-day orbit around Rho Coronae Borealis was discovered in 1997 by observing the star's radial velocity variations. This detection method only gives a lower limit on the true mass of the companion. In 2001, preliminary Hipparcos astrometric satellite data indicated that the orbital inclination of the star's companion was 0.5°, nearly face-on, implying that its mass was as much as 115 times Jupiter's. A paper published in 2011 supported this claim using a new reduction of the astrometric data, with an updated mass value of 169.7 times Jupiter, with a 3σ confidence region 100.1 to 199.6 Jupiter masses. Such a massive body would be a dim red dwarf star, not a planet.

In 2016, however, a paper was published that used interferometry to rule out any stellar companions to this star, in addition to detecting a second planetary companion in a 102-day orbit. Another two planets were discovered in 2023.

The evolution of the parent star, nearing the conclusion of its life cycle, has been regarded as a model for the potential evolution of our planetary system. This is especially relevant for predicting whether the Sun will eventually engulf the Earth at the end of its own lifecycle (cf. Future of Earth).

The Rho Coronae Borealis planetary system
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
e ≥3.79+0.53
−0.54 M🜨 		0.1061±0.0011 12.949±0.014 0.126+0.054
−0.078 		— —
b ≥1.093±0.023 MJ 0.2245+0.0023
−0.0024 		39.8438±0.0027 0.038±0.0025 — —
c ≥28.2±1.5 M🜨 0.4206+0.0044
−0.0045 		102.19+0.27
−0.22 		0.096+0.053
−0.054 		— —
d ≥21.6±2.5 M🜨 0.827±0.011 282.2+2.2
−3.7 		0.0 — —

Circumstellar material

In October 1999, astronomers at the University of Arizona announced the existence of a circumstellar disk around the star. Follow-up observations with the Spitzer Space Telescope failed to detect any infrared excess at 24- or 70-micrometre wavelengths, which would be expected if a disk were present. No evidence for a disk was detected in observations with the Herschel Space Observatory either.

See also

References

  1. ^ 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. ^ Brewer, John M.; Zhao, Lily L.; et al. (June 2023). "EXPRES IV: Two Additional Planets Orbiting ρ Coronae Borealis Reveal Uncommon System Architecture". The Astronomical Journal. 166 (2): 46. arXiv:2306.06888. Bibcode:2023AJ....166...46B. doi:10.3847/1538-3881/acdd6f.
  3. ^ von Braun, Kaspar; et al. (2014). "Stellar diameters and temperatures - V. 11 newly characterized exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 438 (3): 2413–2425. arXiv:1312.1792. Bibcode:2014MNRAS.438.2413V. doi:10.1093/mnras/stt2360.
  4. ^ Fuhrmann, Klaus; Pfeiffer, Michael J.; Bernkopf, Jan (1998). "F- and G-type stars with planetary companions: Upsilon Andromedae, rho (1) Cancri, tau Bootis, 16 Cygni and rho Coronae Borealis". Astronomy and Astrophysics. 336: 942. Bibcode:1998A&A...336..942F.
  5. ^ Metcalfe, Travis S.; Van Saders, Jennifer L.; Basu, Sarbani; Buzasi, Derek; Drake, Jeremy J.; Egeland, Ricky; Huber, Daniel; Saar, Steven H.; Stassun, Keivan G.; Ball, Warrick H.; Campante, Tiago L.; Finley, Adam J.; Kochukhov, Oleg; Mathur, Savita; Reinhold, Timo; See, Victor; Baliunas, Sallie; Soon, Willie (2021). "Magnetic and Rotational Evolution of ρ CrB from Asteroseismology with TESS". The Astrophysical Journal. 921 (2): 122. arXiv:2108.01088. Bibcode:2021ApJ...921..122M. doi:10.3847/1538-4357/ac1f19. S2CID 236881312.
  6. ^ Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  7. ^ 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.
  8. ^ Noyes, Robert W.; et al. (1997). "A Planet Orbiting the Star ρ Coronae Borealis". Astrophysical Journal. 483 (2): L111–L114. arXiv:astro-ph/9704248. Bibcode:1997ApJ...483L.111N. doi:10.1086/310754. S2CID 115606006.
  9. ^ Han, Inwoo; Black, David C.; Gatewood, George (2001). "Preliminary Astrometric Masses for Proposed Extrasolar Planetary Companions". The Astrophysical Journal. 548 (1): L57–L60. Bibcode:2001ApJ...548L..57H. doi:10.1086/318927.
  10. ^ Reffert, S.; Quirrenbach, A. (2011). "Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs". Astronomy & Astrophysics. 527. id.A140. arXiv:1101.2227. Bibcode:2011A&A...527A.140R. doi:10.1051/0004-6361/201015861. S2CID 54986291.
  11. ^ Fulton, Benjamin J.; et al. (October 2016). "Three Temperate Neptunes Orbiting Nearby Stars". The Astrophysical Journal. 830 (1): 46. arXiv:1607.00007. Bibcode:2016ApJ...830...46F. doi:10.3847/0004-637X/830/1/46. S2CID 36666883.
  12. ^ O'Callaghan, Jonathan. "New Clues for What Will Happen When the Sun Eats the Earth". www.quantamagazine.org. Retrieved 30 December 2023.
  13. ^ Trilling, D. E.; Brown, R. H.; Rivkin, A. S. (2000). "Circumstellar Dust Disks around Stars with Known Planetary Companions". The Astrophysical Journal. 529 (1): 499–505. Bibcode:2000ApJ...529..499T. doi:10.1086/308280. S2CID 121999545.
  14. ^ Beichman, C. A.; Bryden, G.; Rieke, G. H.; Stansberry, J. A.; Trilling, D. E.; Stapelfeldt, K. R.; Werner, M. W.; Engelbracht, C. W.; et al. (2005). "Planets and Infrared Excesses: Preliminary Results from a Spitzer MIPS Survey of Solar-Type Stars". The Astrophysical Journal. 622 (2): 1160–1170. arXiv:astro-ph/0412265. Bibcode:2005ApJ...622.1160B. doi:10.1086/428115. S2CID 6633656.
  15. ^ Bryden, G.; Beichman, C. A.; Carpenter, J. M.; Rieke, G. H.; Stapelfeldt, K. R.; Werner, M. W.; Tanner, A. M.; Lawler, S. M.; et al. (2009). "Planets and Debris Disks: Results from a Spitzer/MIPS Search for Infrared Excess". The Astrophysical Journal. 705 (2): 1226–1236. Bibcode:2009ApJ...705.1226B. doi:10.1088/0004-637X/705/2/1226.
  16. ^ Caer McCabe & Carlotta Pham. "Catalog of withdrawn or refuted resolved Disks". Catalog of Resolved Circumstellar Disks. Archived from the original on 2009-01-05. Retrieved 2010-04-03.
  17. ^ Marshall, J. P.; Moro-Martín, A.; Eiroa, C.; Kennedy, G.; Mora, A.; Sibthorpe, B.; Lestrade, J.-F.; Maldonado, J.; et al. (2014). "Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel". Astronomy & Astrophysics. 565. id.A15. arXiv:1403.6186. Bibcode:2014A&A...565A..15M. doi:10.1051/0004-6361/201323058. S2CID 2804652.


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