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HD 154857 is a star with two exoplanetary companions in the southern constellation of Ara. It is too dim to be visible with the naked eye having an apparent visual magnitude of 7.25. The star is located at a distance of 207 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +28 km/s.

This is a G-type star with a stellar classification of G5IV-V. The absolute magnitude of this star is two magnitudes above the main sequence, which suggests that the star is evolving toward the subgiant stage. It is a metal-poor thin disk star approximately six billion years old and is chromopherically quiet although not in a Maunder Minimum state. The star is larger, more massive, and more luminous than the Sun. It is spinning with a projected rotational velocity of 1.4 km/s.

Planetary system

The discovery of one confirmed and one unconfirmed Jovian exoplanet was reported in 2004 and 2007 respectively. The former planet HD 154857 b has mass >1.8 times that of Jupiter. It orbits the star 20% further than Earth-Sun distance, taking 409 days with 47% eccentricity. The additional object (HD 154857 c) was confirmed as a planetary companion in January 2014.

See also

• List of extrasolar planets

References

1. ^ 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.
2. ^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
3. ^ McCarthy, Chris; et al. (2004). "Multiple Companions to HD 154857 and HD 160691". The Astrophysical Journal. 617 (1): 575–579. arXiv:astro-ph/0409335. Bibcode:2004ApJ...617..575M. doi:10.1086/425214. S2CID 119446133.
4. ^ Bonfanti, A.; Ortolani, S.; Nascimbeni, V. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
5. ^ Wittenmyer, Robert A.; et al. (March 2014). "The Anglo-Australian Planet Search. XXIII. Two New Jupiter Analogs". The Astrophysical Journal. 783 (2): 9. arXiv:1401.5525. Bibcode:2014ApJ...783..103W. doi:10.1088/0004-637X/783/2/103. S2CID 14082923. 103.
6. Sousa, S. G.; et al. (November 2018). "SWEET-Cat updated. New homogenous spectroscopic parameters". Astronomy & Astrophysics. 620: 13. arXiv:1810.08108. Bibcode:2018A&A...620A..58S. doi:10.1051/0004-6361/201833350. S2CID 119374557. A58.
7. ^ Butler, R. P.; et al. (December 2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701. S2CID 119067572.
8. "HD 154857". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-10.
9. Gonzalez, Guillermo (October 2009). "Stars with planets and the thick disc". Monthly Notices of the Royal Astronomical Society: Letters. 399 (1): L103 – L107. Bibcode:2009MNRAS.399L.103G. doi:10.1111/j.1745-3933.2009.00734.x.
10. O'Toole, Simon J.; et al. (2007). "New Planets around Three G Dwarfs". The Astrophysical Journal. 660 (2): 1636–1641. arXiv:astro-ph/0702213. Bibcode:2007ApJ...660.1636O. doi:10.1086/513563. S2CID 118958847.

External links

• "HD 154857". Extrasolar Planets Encyclopaedia. Archived from the original on July 2, 2007. Retrieved 2008-07-21.
• http://planetquest.jpl.nasa.gov

v t e Constellation of Ara
Ara in Chinese astronomy List of stars in Ara
Stars	Bayer α (Choo/Tchou) β γ δ ε ε ζ (Tseen Yin) η θ ι κ λ μ (Cervantes) ν (V539) ν π ρ ρ σ Variable R S OY V626 V821 V828 V829 V854 V862 V872 HR 6177 6187 6207 6236 6251 6253 6297 6300 6312 6323 6408 6416 (41 G.) 6423 6438 6477 6478 6483 6487 6513 6759 HD 152079 153201 154672 154857 156411 (Inquill) Other 2MASS J18082002−5104378 CXOU J164710.2−455216 Gliese 674 Gliese 676 IRAS 16594-4656 SAO 244567 SGR 1627−41 Westerlund 1-20 Westerlund 1 W26 Westerlund 1-75 Westerlund 1-237 Westerlund 1-243 XTE J1650−500
Exoplanets Gliese 674 b HD 154672 b HD 154857 b c HD 156411 b μ Arae b c d e
Star clusters	NGC 6193 6200 6204 6208 6250 6352 6362 6397 Other ESO 280-SC06 IC 4651 Westerlund 1
Nebulae	NGC 6188 6326 Other Stingray Nebula Water Lily Nebula
Galaxies	NGC 6215 6221 6300 6328
Category

• G-type subgiants
• Planetary systems with two confirmed planets
• Ara (constellation)
• Durchmusterung objects
• Henry Draper Catalogue objects
• Hipparcos objects