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View Full Version : Vega Has a Cool Dark Equator



Fraser
2006-Jan-11, 06:44 AM
SUMMARY: According to new observations from the National Optical Astronomy Observatory, Vega appears to have a huge difference in temperature between its equator and poles. Vega is the 5th brightest star in the sky, completing one rotation every 12.5 hours. Its high rotation speed flattens out the star, so that it's equator is 23% wider than its polar diameter. This result confirms the theory that rapidly rotating stars are cooler at their equators.

View full article (http://www.universetoday.com/am/publish/vega_cool_dark_equator.html)
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nrbdo
2006-Jan-12, 08:25 PM
I'm new to the forum and not a scientist or math expert. I was just wondering if one of you mathematically adept out there could figure out how fast an object on the surface of Vega would be moving in its rotational velocity as measured along the surface? The fact that it is at 92% of the maximum allowed begs the answer. Thanks

Greg
2006-Jan-13, 03:43 AM
This finding makes this star one of the most interesting in the sky. The implications for the evolution of its planetary system are enormous. I was wondering how such rapid rotation might impact on the expected lifespan of the star. I was also wondering whether its average luminosity rather than the luminosity that we appreciate from our polar vantage point should be applied when making calculations about its interior.

formulaterp
2006-Jan-15, 01:49 PM
I was just wondering if one of you mathematically adept out there could figure out how fast an object on the surface of Vega would be moving in its rotational velocity as measured along the surface?

275 km/s according to this link: http://www.aas.org/publications/baas/v37n4/aas207/654.htm

Just a shade more than 600,000 mph. For comparison's sake, the equatorial velocity of the earth is 1037 mph.