Physical Properties
Arcturus is a type K1.5 IIIpe orange giant star—the letters "pe" stand for "peculiar emission," which indicates that the spectrum of light given off by the star is unusual and full of emission lines. This is not too uncommon in red giants, but Arcturus has a particularly strong case of the phenomenon. It is at least 110 times visually more luminous than the Sun, but this underestimates its strength as much of the "light" it gives off is in the infrared; total (bolometric) power output is about 180 times that of the Sun. The lower output in visible light is due to a lower efficacy as the star has a lower surface temperature than the Sun. With a near-infrared J band magnitude of -2.2, only Betelgeuse (-2.9) and R Doradus (-2.6) are brighter.
Read more about this topic: Arcturus
Famous quotes containing the words physical and/or properties:
“Unfortunately, moral beauty in artlike physical beauty in a personis extremely perishable. It is nowhere so durable as artistic or intellectual beauty. Moral beauty has a tendency to decay very rapidly into sententiousness or untimeliness.”
—Susan Sontag (b. 1933)
“A drop of water has the properties of the sea, but cannot exhibit a storm. There is beauty of a concert, as well as of a flute; strength of a host, as well as of a hero.”
—Ralph Waldo Emerson (18031882)