By Ron Cowen
Astronomers have found a planet that’s the closest yet known to its parent star. It resides 3.5 million kilometers away from the star, less than one-sixteenth Mercury’s distance from the sun. The planet takes 28 hours and 33 minutes to complete an orbit, beating the previous record holder by a half-hour (SN: 1/18/03, p. 38: Available to subscribers at Distant and Strange: Orb isn’t just another extrasolar planet).
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Both close-in planets were revealed by a periodic dip in starlight, suggesting that a small body is regularly passing in front of a star, as seen from Earth. This planet-hunting technique is called the transit method.