Facts about Arcturus

1. 09

   Approximately 7,500 years ago, Arcturus served as the pole star in Earth's night sky due to precession, a role it will resume in roughly 100,000 years.

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2. 08

   Arcturus's surface temperature of approximately 3,700 Kelvin makes it significantly cooler than our Sun's 5,778 Kelvin, characteristic of its red giant classification.

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3. 07

   Spectroscopic analysis reveals that Arcturus contains significantly lower levels of heavy elements than our Sun, with a metallicity about 50 percent of solar abundance.

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4. 06

   Arcturus rotates with a period of approximately 142 days, significantly slower than the Sun's 25-day rotation due to its evolved red giant status and greatly expanded atmosphere.

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5. 05

   In 1933, astronomer Frank Elmore Ross identified Arcturus as a member of the Arcturus Stream, a group of stars sharing similar velocities through the galaxy and suggesting a common origin from a disrupted globular cluster.

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6. 04

   Arcturus harbors a debris disk or planetary system indicated by excess infrared radiation detected by the Spitzer Space Telescope at wavelengths around 70 micrometers.

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7. 03

   Arcturus possesses an unusually large radius of approximately 25 times the Sun's, making it an evolved red giant near the end of its stellar life cycle.

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8. 02

   At approximately 37 light-years distant, Arcturus moves through space at 122 kilometers per second, making it one of the fastest-moving stars in our galactic neighborhood.

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9. 01

   The bright orange giant Arcturus shines at magnitude 0.04, making it the fourth brightest star visible from Earth.

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