HD 32518 is a star with an orbiting exoplanet in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 6.42,[2] placing it near the limit of naked eye visibility. Located 397 light years away based on parallax measurements,[1] it is receding with a heliocentric radial velocity of −7.02 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 05h 09m 36.720s[1] |
| Declination | +69° 38′ 21.85″[1] |
| Apparent magnitude (V) | 6.42±0.01[2] |
| Characteristics | |
| Evolutionary stage | Horizontal branch[3] |
| Spectral type | K1 III[4] |
| U−B color index | +1.03[5] |
| B−V color index | +1.11[5] |
| Astrometry | |
| Radial velocity (Rv) | –7.02±0.35[6] km/s |
| Proper motion (μ) | RA: +61.031 mas/yr[1] Dec.: −62.382 mas/yr[1] |
| Parallax (π) | 8.2192 ± 0.0166 mas[1] |
| Distance | 396.8 ± 0.8 ly (121.7 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.04[7] |
| Details | |
| Mass | 1.2±0.1[8] M☉ |
| Radius | 10.8±0.3[8] R☉ |
| Luminosity | 46.4±0.9[8] L☉ |
| Surface gravity (log g) | 2.48[3] cgs |
| Temperature | 4,731[3] K |
| Metallicity [Fe/H] | +0.04[3] dex |
| Rotational velocity (v sin i) | 1.2±2[9] km/s |
| Age | 6.4±1.5[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 32518 has a stellar classification of K1 III,[4] indicating that it is an orange giant star that has evolved away from the main sequence. Located in the cool end in the red clump, the object is currently on the horizontal branch.[3] This indicates it is generating energy by helium fusion at the core. It has 1.2 the mass of the Sun[8] but has expanded to a radius of 10.8 R☉.[8] It shines at 46.4 times the luminosity of the Sun[8] from its enlarged photosphere at an effective temperature of 4,731 K,[3] giving it a yellowish orange glow. HD 32518 is older than the Sun with an age of 6.4 billion years[8] and spins slowly with a projected rotational velocity of 1.2 km/s−1.[9] However, this amount is poorly constrained. As for its metallicity, studies place it around solar level.[3]
Planetary system
editIn August 2009, a group of astrometers discovered a super-jovian exoplanet orbiting the giant star using doppler spectroscopy.[11]
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.[12][13][14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (Neri) | ≥3.04 ± 0.69 MJ | 0.59 ± 0.03 | 157.54 ± 0.38 | 0.01 ± 0.03 | — | — |
See also
editReferences
edit- ^ a b c d e 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.
- ^ a b 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.
- ^ a b c d e f g 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.
- ^ a b 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.
- ^ a b 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.
- ^ a b Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data: Revisiting the concept of superclusters". Astronomy & Astrophysics. 430 (1): 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. ISSN 0004-6361.
- ^ 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.
- ^ a b c d e f g h 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.
- ^ a b 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.
- ^ "HD 32518". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-12-14.
- ^ a b 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.
- ^ "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
- ^ "Approved names". NameExoworlds. Retrieved 2020-01-02.
- ^ "Abstimmung über Exoplaneten-Namen: Planet Neri umkreist Stern Mago". www.haus-der-astronomie.de. Retrieved 2020-01-02.