39 Arietis
 39 Arietis in optical light | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aries |
| Right ascension | 02h 47m 54.54142s[1] |
| Declination | +29° 14′ 49.6132″[1] |
| Apparent magnitude (V) | 4.514[2] |
| Characteristics | |
| Spectral type | K1.5 III[3] |
| U−B color index | +1.083[2] |
| B−V color index | +1.118[2] |
| R−I color index | 0.58 |
| Astrometry | |
| Radial velocity (Rv) | –15.53 ± 0.14[4] km/s |
| Proper motion (μ) | RA: +149.47 ± 0.25[1] mas/yr Dec.: –127.05 ± 0.18[1] mas/yr |
| Parallax (π) | 19.01 ± 0.21 mas[1] |
| Distance | 172 ± 2 ly (52.6 ± 0.6 pc) |
| Details | |
| Mass | 1.6[5] M☉ |
| Radius | 11.1 ± 0.8[3] R☉ |
| Luminosity | 56[4] L☉ |
| Surface gravity (log g) | 2.7[4] cgs |
| Temperature | 4,603[4] K |
| Metallicity [Fe/H] | –0.02[4] dex |
| Rotational velocity (v sin i) | 4.5[4] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
39 Arietis (abbreviated 39 Ari), officially named Lilii Borea /ˈlɪliaɪ ˈbɔːriə/,[7] is a star in the northern constellation of Aries. It is visible to the naked eye with an apparent visual magnitude of +4.5.[2] The distance to this star, as determined from an annual parallax shift of 19.01 mas,[1] is approximately 172 light-years (53 parsecs). This star was formerly located in the obsolete constellation Musca Borealis.
Nomenclature[edit]
39 Arietis is the star's Flamsteed designation.
This star was described as Lilii Borea by Nicolas-Louis de Lacaille in 1757,[8][9] as a star of the now-defunct constellation of Lilium (the Lily). The words are simply the Latin phrase Līliī Boreā 'in the north of Lilium'. Līliī Austrīnā /ɔːˈstraɪnə/ 'in the south of Lilium' was 41 Arietis.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalog and standardize proper names for stars. The WGSN approved the name Lilii Borea for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[7]
In Chinese, 胃宿 (Wèi Su), meaning Stomach, refers to an asterism consisting of 39 Arietis, 35 Arietis and 41 Arietis.[11] Consequently, the Chinese name for 39 Arietis itself is 胃宿二 (Wèi Su èr, English: the Second Star of Stomach).[12]
Properties[edit]
39 Arietis is a giant star with a stellar classification of K1.5 III.[3] It is currently at an evolutionary stage known as the red clump, indicating that it is generating energy through the fusion of helium at its core.[5] It has 1.6[5] times the mass of the Sun, but its outer envelope has expanded to around 11[3] times the Sun's radius. It shines with 56 times the luminosity of the Sun.[4] This energy is being radiated into outer space from its outer atmosphere at an effective temperature of 4,603 K,[4] giving it the cool orange-hued glow of a K-type star.[13]
See also[edit]
References[edit]
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d Oja, T. (1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–4, Bibcode:1986A&AS...65..405O.
- ^ a b c d Nordgren, Tyler E.; et al. (December 1999), "Stellar Angular Diameters of Late-Type Giants and Supergiants Measured with the Navy Prototype Optical Interferometer", The Astronomical Journal, 118 (6): 3032–3038, Bibcode:1999AJ....118.3032N, doi:10.1086/301114
- ^ a b c d e f g h Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- ^ a b c Tautvaišienė, G.; et al. (December 2010), "C, N and O abundances in red clump stars of the Milky Way", Monthly Notices of the Royal Astronomical Society, 409 (3): 1213–1219, arXiv:1007.4064, Bibcode:2010MNRAS.409.1213T, doi:10.1111/j.1365-2966.2010.17381.x, S2CID 119182458.
- ^ "* 39 Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-18.
- ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
- ^ de Lacaille, Nicolas-Louis (1757). Astronomiae fundamenta novissimis solis et stellarum observationibus stabilita, Lutetiae in Collegio mazarineo et in Africa ad caput Bonae Spei peractis a Nicolao Ludovico de La Caille. J.-J.-St. Collombat. pp. 227, 233.
- ^ Baily, Francis (1833). La Caille's Catalogue of 398 principal Stars, Memoirs of the Royal Astronomical Society, Vol 5. Priestley and Weale. pp. 110, 121.
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (in Chinese) 白羊座
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on February 22, 2012, retrieved 2012-01-16
