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Aleksander Wolszczan and Copernicus, Stamp

Aleksander Wolszczan (b. 1946 in Szczecinek, Poland) is a Polish astronomer. He was the discoverer of the first extrasolar planets and pulsar planets.


Educated in Poland (at the Nicolaus Copernicus University in Toruń), Wolszczan moved in 1982 to the U.S. to work at Cornell University in Ithaca and Princeton University. Later he became an astronomy professor at the Pennsylvania State University. Concurrent with that appointment, since 1994 he has been a professor at the University in Toruń and a member of the Polish Academy of Sciences (PAN).

Working with Dale Frail, he carried out astronomical observations from the Arecibo Observatory which led them to the discovery of the pulsar PSR B1257+12 in 1990. The data analysis gathered thanks to the discovery showed that the pulsar is orbited by two planets with masses at least 3.4 and 2.8 times that of Earth's mass. Their orbits are 0.36 and 0.47 AU respectively. This planetary system was the first extra-solar system discovered in the Universe whose existence was proved.

Wolszczan and Frail published their findings in 1992 and 1994. In spite of initial misgivings of some experts, today this discovery is regarded as fully substantiated.

In 1996, Wolszczan was awarded the Beatrice M. Tinsley Prize by the American Astronomical Society.

In 2003 Konacki and Wolszczan determined the orbital inclinations of the two planets, showing that the actual masses are approximately 3.9 and 4.3 Earth masses.


* Wolszczan, A., and D.A. Frail. A planetary system around the millisecond pulsar PSR 1257+12. Nature 355(6356):145-7, January 9, 1992.

* Wolszczan, A. Confirmation of Earth-mass planets orbiting the millisecond pulsar PSR B1257+12. Science 264(5158):538-42, April 22, 1994.

* Konacki, M. and Wolszczan, A. Masses and Orbital Inclinations of Planets in the PSR B1257+12 System Astrophysical Journal, Volume 591, Issue 2, pp. L147-L150, 2003.

See also

* Pulsar planet

* Extrasolar planet

* List of stars with confirmed extrasolar planets


* Earth Sized Planets Confirmed


Astronomy Encyclopedia

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