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Swarthmore Astronomers Discover New Star in Southern Cross

Contact: Alisa Giardinelli


Swarthmore Astronomers Discover
New Star in Southern Cross


A research team at Swarthmore College discovered a previously unknown companion to the bright star, beta Crucis, in the Southern Cross. As a prominent member of the well-known constellation Crux, or the Southern Cross, it appears on several national flags, including Australia, Brazil, New Zealand, Papua New Guinea, and Samoa.  The discovery was announced at the American Astronomical Society meeting held in Seattle Jan. 5-10 and has since made headlines in The New York Times, among several other news sources.

The companion star was discovered accidentally while the research team was using the orbiting Chandra X-ray Observatory to study the x-rays emitted by beta Crucis  itself.  "We were interested in how the highly supersonic stellar winds of hot, luminous stars produce x-rays," says team leader David Cohen, asssociate professor of astronomy. "We were surprised to see two strong x-ray sources where we had expected to see only one."

Clockwise, the Southern Cross is prominently displayed on Australia's flag, with beta Crucis just right of the Union Jack; an optical image of the Southern Cross, with beta Crucis indicated by the yellow rectangle and its newly discovered companion shown at the lower left; the Chandra image is color coded, with high energy x-rays colored blue, medium energy x-rays colored green, and lower energy x-rays colored red.

Astrophysics major Michael Kuhn '07 (right) presented the findings at the American Astronomical Society meeting January 9.

Astrophysics major Michael Kuhn '07 of Charlottesville, Va., presented the findings in Seattle.  His work analyzing the x-ray data from both beta Crucis and its newly-discovered companion is the basis for a forthcoming paper on this project in the Monthly Notices of the Royal Astronomical Society. 

Cohen' s research team also includes Swarthmore College Associate Professor of Astronomy Eric Jensen and Marc Gagné, associate professor in the geology and astronomy department at West Chester University of Pennsylvania.  Their project was funded by NASA and by a Eugene M. Lang Summer Research Fellowship from Swarthmore.

Learn more (pdf).





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