SPACE.com -- Astronomers Create First Detailed Movie of Distant Star

Click to watch. This movie, made by the Very Long Baseline Array, shows the churning gases coming off of the star TX Cam. The movie covers 88 weeks of data, with images taken once every two weeks. Credit: P.Diamond/A.Kemball

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	Astronomers Create First Detailed Movie of Distant Star By Maia Weinstock Staff Writer posted: 07:00 am ET 15 August 2000

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When you think of movie stars, you probably think Hollywood, glitz and glamour. But this week, astronomers have released the first-ever detailed movie of another kind of star, a distant sun lying some 1,000 light-years from Earth.

Using the National Science Foundations Very Long Baseline Array (VLBA), two astronomers made a time-lapse movie from repeated observations of a star called TX Cam, which is located in the constellation Camelopardalis. Though astronomers have made similar movies of our own sun using the Solar Heliospheric Observatory (SOHO) spacecraft in the past, this marks the first time a detailed movie has been created of a star other than our sun.

The circle in these two frames of the TX Cam movie has been added to show the approximate size of the star.

Philip Diamond of the Jodrell Bank Observatory in England and Athol Kemball of the National Radio Astronomy Observatory in New Mexico used a method called Very Long Baseline Interferometry (VLBI) to catch TX Cam in action. VLBI involves capturing radio beams coming from the star with a group of 10 antennas spread across the United States, from Hawaii to the Virgin Islands.

TX Cam is known as a "Mira variable star," after the star Mira, which goes through a cyclical change in brightness. TX Cam changes its brightness over a period of about 80 weeks, or about a year and a half. Diamond and Kemballs entire movie covers 88 weeks just over one cycle with one observation being made every two weeks. The images used to make the movie are 500 times more detailed than what would be possible to witness with the Hubble Space Telescope.

Theory holds that our own sun will one day end up like TX Cam and other Mira stars. Our sun is currently about 4.5 billion years old, about halfway through its lifetime. In another few billion years, the sun will grow immensely in size, filling up the inner solar system and engulfing planets along the way. Mira stars are believed to represent this same bloated point in star devolution.

Diamond and Kemballs movie shows gases flailing to and from TX Cams surface. However, the astronomers arent sure as to the exact nature of the gases seen moving chaotically near the star. According to Diamond, the gases "show immensely complex motions which cannot be explained by current theory."

In order to learn more about the stars behavior and evolution, Diamond and Kemball have already planned future studies of TX Cam with the Very Large Baseline Array. They hope to incorporate more images of TX Cam into their already-existing movie so that they come to a more complete understanding of the stars pulsating gas ejection.