THE PERSIAN (Alpha Indi). Stars are named by many cultures in many languages. These pages use star names appropriate to the "western" constellations, which were actually born in the ancient lands of the middle east. Gamma Cassiopeiae, for example, has no "western" name (usually of Greek, Roman, or Arabic origin), and is consequently known here simply as Gamma Cas in spite of the fact that it is known as "Tsih" (whip) in China. Here is an unusual crossover, a star that while apparently named in China, still fits into "western" lore, in that it was named "the Persian" (for unknown reasons) by Jesuit missionaries. The star is doubly unusual in that it is only one of a handful found within "modern" constellations (mostly dim figures that were born between about 1600 and 1800) that carry proper names. Though the luminary of the modern constellation Indus, the Indian, and carrying the Alpha designation, the Persian is still only third magnitude (3.11) and not well known in the mid-north as it is so far south that it just skims the horizon (while in mid- southern latitudes passing nearly overhead). The Persian is at first a common class K (K0) orange giant of 2 to 3 solar masses, a dying star that is fusing its core helium into carbon and oxygen. At a distance of 101 light years, it shines 62 times more brightly than does the Sun from a surface that has a temperature of 4860 Kelvin and a radius 11 times solar. It distinguishes itself in a couple ways, first in its composition. While apparently somewhat diminished in carbon and/or nitrogen, it is among a class of "super-metal-rich" stars, in which metals and other heavy elements are enhanced, here iron up over solar by nearly a factor of two. Such stars were apparently born in interstellar clouds interior to the Sun's path around the Galaxy that have been enriched by high rates of stellar evolution (in which heavy elements created in stars are launched into space by winds and explosions). The Persian also has a pair of dim companions. From their brightness (12th and 13th magnitude), they must be low-mass class M red dwarfs, each at least 2000 astronomical units from, and on nearly opposite sides of, the Persian, and taking at least 50,000 years to orbit. From each, the Persian would appear 10 times brighter than our full Moon, while the other dimmer star would shine perhaps as bright as a red Venus.
Written by Jim Kaler. Return to STARS.