Arcturus Star: Characteristics, Luminosity, Interesting Facts

Throughout the course of human civilization, celestial bodies that traverse the coordinates of the night sky have been bestowed with a multitude of poetic names. Among these luminaries stands the orange-hued star known to us today as Arcturus.

One ancient legend tells that thanks to this luminary, sailors found their way home after long voyages. Another story suggests that it was Arcturus who led the Magi to the cradle of Jesus.

Key Characteristics of Arcturus:

• Arcturus is an orange giant star that could eventually transform into a white dwarf.
  It is the Alpha star in the constellation of Boötes, forming this constellation along with 50 other stars. Ancient Greek scientists called this asterism Arctophylax, and in Ptolemy’s catalog, this group of celestial bodies is mentioned as Almagest.
• Arcturus is 110 times brighter than the Sun, and its radius is approximately 25 times that of the Sun. However, the mass of both stars is roughly the same.
  Arcturus has a spectral class of K2IIIpe.
• Due to nuclear reactions, the surface temperature of the star warms up to 4000 degrees Celsius or 4290 Kelvin.
• Its distance from the Solar System is 11.3 parsecs (36.7 light-years).
• Luminosity of Arcturus: In the optical range, the orange giant has a luminosity ranging from 170 to 215 L☉. These fluctuations are due to different times of day, changing seasons, and the specific latitudes from which observation is conducted. Arcturus reaches culmination twice a year – at 00:00 on April 27 and at 21:00 on June 10.

The apparent magnitude of Arcturus is -0.05, while its absolute magnitude reaches -0.30. This celestial body is considered the fourth brightest object in the night sky (brighter only than Sirius, Canopus, and the Alpha Centauri system).

Arcturus is 36.7 light-years away from the Sun. It is currently considered a close neighbor to Earth. However, in about one and a half million years, the orange giant will drift so far away from our world that it will be difficult to see even through a telescope.

Interesting Facts About Arcturus:

1. The celestial body was discovered in the 17th century by the astronomer named Morin. As usual, the discovery happened by chance – the researcher simply noticed a bright spot and became interested in it.
2. Arcturus can be seen from almost any point on the planet without a telescope. To do this, you just need to draw an imaginary arc through the handle of the Big Dipper. Arcturus will be its visual extension.
3. The star is visible before sunset, which is why it is often called the “evening star” or the “first star,” on which it is customary to make a wish.
4. Arcturus surpasses the Sun in all parameters: it gives off 110 times more light, has a diameter 30 times larger, and is twice as old.
5. The giant does not contain heavy metals in its composition, so despite its huge size, it is very light.
6. There is a hypothesis that Arcturus will soon (in cosmic terms) transform into a white dwarf since it has almost exhausted its entire hydrogen supply.
7. The cosmic body is mentioned in the popular science fiction series “Doctor Who” and in literary works, such as those by S. Lem and D. Lindsay.