Alpha Fornacis
The brightest star in Fornax, a triple system 45.66 light-years away.
Alpha Fornacis, also known as α Fornacis, is a triple star system in the southern constellation Fornax. Its combined apparent magnitude of 3.92 makes it the constellation's brightest star, and the only one above magnitude 4.0. Gaia parallax data places it 45.66 light-years from Earth.
Quick Facts
- Bayer designation
- α Fornacis
- Apparent magnitude
- 3.92
- Distance
- 45.66 light-years
- Constellation
- Fornax
- Spectral type (a)
- F6V
- Mass (a)
- 33% more than the Sun
- Age (a)
- 2.9 billion years
Facts from the source article.
Nomenclature
The Bayer designation for this system is α Fornacis, Latinised to Alpha Fornacis. Its components are designated Alpha Fornacis A, Ba, and Bb according to the Washington Multiplicity Catalog convention, adopted by the International Astronomical Union. Formerly, Flamsteed designated it as 12 Eridani. Indigenous Arabs used the word ظَلِيم (al-ẓalīm, meaning 'ostrich') for both Alpha Eridani and Fomalhaut; later Arabian astronomers transferred the name to Theta Eridani. Italian astronomer Giuseppe Piazzi applied the spelling Dalim to his "III 13" (α For) in his Palermo Catalogue, and Elijah Burritt labeled it Fornacis in his Atlas. In 2016, the IAU's Working Group on Star Names approved the name Dalim for Alpha Fornacis A on 5 September 2017, and it is now included in the List of IAU-approved Star Names.
Properties
Alpha Fornacis has a high proper motion and an infrared excess, possibly indicating circumstellar material such as a debris disk. Its space velocity components are (U, V, W) = (−35, +20, +30) km/s. About 350,000 years ago, it had a close encounter with Nu Horologii, coming within 0.265 light-years; both stars have debris disks. Alpha Fornacis A, classified F6V, is a main sequence star near the end of its life, with 33% more mass than the Sun and an estimated age of 2.9 billion years. The secondary, Alpha Fornacis B, is a blue straggler, likely having accumulated material from a third star. It is a strong X-ray source, 78% as massive as the Sun. A third component, Alpha Fornacis Bb, was detected in 2016. Alpha Fornacis Ba is enriched in barium relative to star A, suggesting its companion is probably a white dwarf.
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