November 15, 1999
Somewhere above you, light is arriving from places so distant their names feel like poetry.
In the Shade of a Historic Planet
Birthday · November 15, 1999
A little universe, just for you
Your date.
Ready to give.
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APOD published November 15, 1999. Credit: Lynette Cook. A publication-date match, not a photo taken on your date. Independent of NASA.
For the first time, astronomers have recovered independent evidence that distant planetary systems exist. Last Friday, a team led by G. W. Henry (Tenn. State) and G. Marcy (UC Berkeley) announced the discovery of a shadow of a planet crossing a distant star. Little known HD 209458, a Sun-like star 150 light-years away, had been suspected of harboring planets from a slight wobble found in its motion. Henry et al. now find that this wobble exactly corresponds to a planet crossing the face of the star, creating the slight dimming effect of a partial eclipse. The astronomers were then able to make a groundbreaking estimate of the mass and radius of the extra-solar planet, which they find to have about two-thirds the mass of Jupiter but about 60 percent larger radius. The drawing above is an artist's depiction of a planetary eclipse in the HD 209458 system.
Image credit: Lynette Cook