HD 32518

Last updated
HD 32518 / Mago
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Camelopardalis [1]
Right ascension 05h 09m 36.720s [2]
Declination +69° 38′ 21.85″ [2]
Apparent magnitude  (V)6.42±0.01 [3]
Characteristics
Evolutionary stage Horizontal branch [4]
Spectral type K1 III [5]
U−B color index +1.03 [6]
B−V color index +1.11 [6]
Astrometry
Radial velocity (Rv)−6.78±0.12 [2] km/s
Proper motion (μ)RA: +61.031 mas/yr [2]
Dec.: −62.382 mas/yr [2]
Parallax (π)8.2192±0.0166  mas [2]
Distance 396.8 ± 0.8  ly
(121.7 ± 0.2  pc)
Absolute magnitude  (MV)+1.04 [1]
Details
Mass 1.2±0.1 [7]   M☉
Radius 10.8±0.3 [7]   R☉
Luminosity 46.4±0.9 [7]   L☉
Surface gravity (log g)2.10±0.15 [8]   cgs
Temperature 4,580±70 [8]   K
Metallicity [Fe/H]−0.15±0.04 [8]   dex
Rotational velocity (v sin i)1.2±2 [9]  km/s
Age 6.4±1.5 [7]   Gyr
Other designations
Mago, AG+69°241, BD+69°302, GC 6245, HD 32518, HIP 24003, HR 1636, SAO 13382 [10]
Database references
SIMBAD data
Exoplanet Archive data

HD 32518, also named Mago, is a star with an orbiting exoplanet in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 6.42, [3] placing it near the limit of naked eye visibility. Located 397 light-years away based on parallax measurements, it is receding with a heliocentric radial velocity of −6.8  km/s . [2]

Contents

HD 32518 has a stellar classification of K1 III, [5] indicating that it is an orange giant star that has evolved away from the main sequence. It is currently on the horizontal branch, located at the cool end in the red clump. [4] This indicates it is generating energy by helium fusion at the core. It has 1.2 the mass of the Sun [7] but has expanded to a radius of 10.8  R☉ . [7] It shines at 46.4 times the luminosity of the Sun [7] from its enlarged photosphere at an effective temperature of 4,731  K, [4] giving it a yellowish orange glow. HD 32518 is likely to be somewhat older than the Sun with an age of 6.4 billion years [7] and spins slowly with a projected rotational velocity of 1.2 km/s. [9] Studies place its metallicity around solar level. [4]

For the 100th anniversary of the IAU HD 32518 and the planet HD 32518b were selected NameExoWorlds campaigns for Germany. The approved name of the star HD 32518 is Mago, named after Mago National Park in Ethiopia, which is noted for its giraffes. The name was suggested by pupils of a physics course at the Max-Born-Gymnasium in Neckargemünd. [11] [12] [13]

Planetary system

In August 2009, a group of astrometers discovered a super-jovian exoplanet orbiting the giant star using Doppler spectroscopy. [8] The planetary parameters were updated in 2023. [14]

The HD 32518 planetary system [14]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b (Neri) ≥2.849+0.160
−0.171  MJ 		0.594157.35+0.10
−0.08		0.028+0.034
−0.019		——

See also

References

  1. 1 2 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. ISSN   1063-7737. S2CID   255204555.
  2. 1 2 3 4 5 6 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.
  3. 1 2 Oja, T. (August 1991). "UBV photometry of stars whose positions are accurately known. VI". Astronomy and Astrophysics Supplement Series. 89: 415. Bibcode:1991A&AS...89..415O. ISSN   0365-0138.
  4. 1 2 3 4 Ting, Yuan-Sen; Hawkins, Keith; Rix, Hans-Walter (3 May 2018). "A Large and Pristine Sample of Standard Candles across the Milky Way: ~100,000 Red Clump Stars with 3% Contamination". The Astrophysical Journal. 858 (1): L7. arXiv: 1803.06650 . Bibcode:2018ApJ...858L...7T. doi: 10.3847/2041-8213/aabf8e . ISSN   0004-637X.
  5. 1 2 Halliday, Ian (September 1955). "Luminosity Function and Space Motions of G8-K1 Stars Derived from Spectroscopic Parallaxes". The Astrophysical Journal. 122: 222. Bibcode:1955ApJ...122..222H. doi: 10.1086/146080 . ISSN   0004-637X.
  6. 1 2 Oja, T. (April 1983). "UVB photometry of FK4 and FK4 Supplement stars". Astronomy and Astrophysics Supplement Series. 52: 131–134. Bibcode:1983A&AS...52..131O. ISSN   0365-0138.
  7. 1 2 3 4 5 6 7 8 Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv: 1411.4302 . Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID   54555839.
  8. 1 2 3 4 Döllinger, M.; et al. (2009). "Planetary companions around the K giant stars 11 Ursae Minoris and HD 32518". Astronomy and Astrophysics. 505 (3): 1311–1317. arXiv: 0908.1753 . Bibcode:2009A&A...505.1311D. doi:10.1051/0004-6361/200911702. S2CID   9686080.
  9. 1 2 de Medeiros, J. R.; Mayor, M. (November 1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series. 139 (3): 433–460. Bibcode:1999A&AS..139..433D. doi: 10.1051/aas:1999401 . ISSN   0365-0138.
  10. ↑ "HD 32518". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2023-12-14.
  11. ↑ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  12. ↑ "Approved names". NameExoworlds. Retrieved 2020-01-02.
  13. ↑ "Abstimmung über Exoplaneten-Namen: Planet Neri umkreist Stern Mago". www.haus-der-astronomie.de. Retrieved 2020-01-02.
  14. 1 2 Teng, Huan-Yu; Sato, Bun'ei; et al. (August 2023). "Revisiting planetary systems in the Okayama Planet Search Program: A new long-period planet, RV astrometry joint analysis, and a multiplicity-metallicity trend around evolved stars". Publications of the Astronomical Society of Japan . 75 (6): 1030–1071. arXiv: 2308.05343 . Bibcode:2023PASJ...75.1030T. doi:10.1093/pasj/psad056.
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