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We now offer the Cool It! card game in our Science Store. Cool It! is the new card game from UCS that teaches kids about the choices we have when it comes to climate change.
Hubble Space Telescope image of Sirius, the brightest star in the sky, and its tiny white dwarf companion.
Click on image for full size
NASA, ESA, H. Bond, M. Barstow

Sirius A - Brightest Star in the Sky

What's in a Name: Greek for "Scorcher". Also called the "Dog Star". Sirius was not visible in the night sky during the summer months, therefore the Greeks thought that Sirius added its heat to that of the sun, producing the warm summer months. The hottest days are still called "dog days".
Claim to Fame: Brightest star in the sky (apparent magnitude=-1.5). In a few billion years it should become a giant and then a white dwarf. Now the surface is enriched in metals. Believe Sirius B (its white dwarf companion) passed material to Sirius A during the process of becoming a white dwarf and caused the enrichment.
Type of Star: White Main Sequence Star (A1 V spectral Class)
How Far Away: 8.7 light years away (2.7 parsecs)
How Big: 1.8 times the Sun's diameter
How Bright: 23 times the Sun's luminosity (Mv=+1.4)
Where to View: In the constellation Canis Major (Star Map).
When to View: January through March

Last modified January 25, 2006 by Travis Metcalfe.

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