Nu Fornacis

Nu Fornacis, Latinized from ν Fornacis, is a single,^[13] variable star in the southern constellation of Fornax. It is blue-white in hue and faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.69.^[3] This body is located approximately 370 light years distant from the Sun based on parallax,^[2] and is drifting further away with a radial velocity of +18.5 km/s.^[7] It is a candidate member of the Pisces-Eridanus stellar stream, which suggests an age of 120 million years or less.^[14]

Nu Fornacis

A light curve for Nu Fornacis plotted from TESS data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Fornax
Right ascension	02h 04m 29.43861s[2]
Declination	−29° 17′ 48.5477″[2]
Apparent magnitude (V)	4.69[3] (4.68 – 4.73[4])
Characteristics
Spectral type	B9.5IIIspSi[5]
U−B color index	−0.51[3]
B−V color index	−0.17[3]
Variable type	α2 CVn[6]
Astrometry
Radial velocity (Rv)	+18.50[7] km/s
Proper motion (μ)	RA: +12.79[8] mas/yr Dec.: +8.48[8] mas/yr
Parallax (π)	8.79 ± 0.26 mas[2]
Distance	370 ± 10 ly (114 ± 3 pc)
Absolute magnitude (MV)	−0.60[9]
Details
Mass	3.65±0.18[10] M☉
Radius	3.44[11] R☉
Luminosity	245[10] L☉
Temperature	13,400[12] K
Rotation	1.89[12] d
Rotational velocity (v sin i)	50±5[12] km/s
Other designations
ν For, CD−29°706, FK5 1055, GC 2506, HD 12767, HIP 9677, HR 612, SAO 167532[8]
Database references
SIMBAD	data

This object is an Ap star^[15] with a stellar classification of B9.5IIIspSi^[5] matching a late B-type giant star. The 'Si' suffix indicates an abundance anomaly of silicon. It is an Alpha² Canum Venaticorum variable that ranges from magnitude 4.68 down to 4.73 with a period of 1.89 days – the same as its rotational period.^[6][12] It is 3.65 times as massive and 245 times as luminous as the Sun,^[10] with 3.44 times the Sun's diameter.^[11]

References

1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
2. van Leeuwen, F. (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. Vizier catalog entry
3. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
4. Samus, N. N.; Durlevich, O. V.; et al. (2009). "General Catalogue of Variable Stars". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
5. Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The relation between Rotational Velocities and Spectral Peculiarities among A-type stars". The Astrophysical Journal Supplement Series. 99: 135–172. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
6. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
7. Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Washington. Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W. LCCN 54001336.
8. "* nu. For". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-04-08.
9. 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.
10. North, P. (1998). "Do SI stars undergo any rotational braking?". Astronomy and Astrophysics. 334: 181–87. arXiv:astro-ph/9802286. Bibcode:1998A&A...334..181N.
11. Shulyak, D.; et al. (2014). "Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities". Monthly Notices of the Royal Astronomical Society. 443 (2): 1629. arXiv:1406.6093. Bibcode:2014MNRAS.443.1629S. doi:10.1093/mnras/stu1259.
12. Leone, F.; et al. (2000). "A spectroscopic study of the magnetic chemically peculiar star nu Fornacis". Astronomy and Astrophysics. 359: 635–38. Bibcode:2000A&A...359..635L.
13. Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
14. Curtis, Jason L.; et al. (August 2019). "TESS Reveals that the Nearby Pisces─Eridanus Stellar Stream is only 120 Myr Old". The Astronomical Journal. 158 (2): 11. arXiv:1905.10588. Bibcode:2019AJ....158...77C. doi:10.3847/1538-3881/ab2899. S2CID 166228270. 77.
15. Chen, P. S.; et al. (May 2017). "A New Photometric Study of Ap and Am Stars in the Infrared". The Astronomical Journal. 153 (5): 28. Bibcode:2017AJ....153..218C. doi:10.3847/1538-3881/aa679a. 218.