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Name: Cristi M Carpenter and Sreedevi K Bringi
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Where are the new planets that were recently discovered, located. How many planets are there? What observatory and what research team worked on this project? Was the team that filmed the Astronomer's Searching For Planets on the right track or involved with the discovery? Has anyone ever discovered a planet outside the solar system? If so, can you tell me about it?

The existence of at least two (and possibly as many as four) planets in orbit around the pulsar designated PSR1257+12, in the constellation Virgo, was deduced from slight irregularities in the output of this pulsar due to gravitational "tugs" by the unseen planets. The discovery was made by a team headed by Alexander Wolszczan of Penn State University; the team was assisted by Dale Frail of the National Radio Astronomy Observatory in Green Bank, WV. They used the 305-meter radio dish at Arecibo Observatory in Puerto Rico to make their measurements. I really doubt that these astrono- mers were looking for planets.

I did not see the episode of "The Astronomers" that I believe you are refer- ring to, but it is also written about in the companion book. These astrono- mers have been looking for possible planet-forming disks of material surrounding certain stars. One candidate mentioned in this chapter (and presumably in the TV version) is the star Beta Pictoris. Recently a group of French astronomers reported observations of this star's dust disk that suggest that there are one or more planets within the disk, circling the star. If confirmed, it will indicate that yes, the astronomers filmed in the series were indeed on the right track.

RC Winther

I know of one discovery: a planet has been discovered around a pulsar (a rotating neutron star that emits regular pulses of radiation). No one has seen the planet but its existence has been inferred by studying the orbit of the pulsar and variation (minute) in its pulses. The planet is very massive, even more massive than Jupiter. As the pulsar and planet orbit around each other, the pulsar approaches us and then recedes away from us. We observe regular changes in the frequency of pulses. This is roughly similar to the change in tone of a car horn as the car first approaches you and then recedes.

Jasjeet S Bagla

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