Astronomers Spy Monster Star Merger on the Move

A coming collision could let astronomers peek at the birth of a jumbo star.
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The two stars in the MY Cam system (artist's rendering, above) are so close together that they will end up merging into one supermassive star, astronomers say.


Twin monster stars are merging, astronomers report, in a confirmation of a long-held theory on how supermassive stars are born.

A Spanish astronomy team reports the eclipsing binary star system, known as MY Camelopardalis (MY Cam), in the journal Astronomy & Astrophysics. From Earth, the system's two gigantic stars appear to eclipse one another almost every day, as they circle on a very tight orbit.

By looking at the high-resolution spectra of the two stars with the powerful 2.2-meter telescope at the Calar Alto Observatory in southern Spain, the researchers, led by Javier Lorenzo of Spain's Universidad de Alicante, were able to determine the physical properties of each of the stars, including their surface temperatures and sizes.

The two hot, blue stars, weighing in at 38 and 32 times the mass of our sun, complete orbits of each other in less than 1.2 days. That is so close that the team concludes they are inevitably destined to merge into a single behemoth star, one that will have an astounding 60 times the mass of the sun.

The authors of the recently published study show that MY Cam is already one of the heftiest binary star systems ever seen. In fact, the two stars are likely close enough that their outer atmospheres are already touching and interacting. They are also rotating around each other at whopping speeds of 621,000 miles (one million kilometers) per hour.

Astronomical Eclipses

MY Cam was discovered to be a binary system only about a decade ago. Amateur astronomers had been viewing what looked like a single star for years, and had misclassified it as a variable star that fluctuated in brightness. We now know this change in brightness is due to one star rapidly eclipsing the other as they circle around each other.

Astronomers believe that both jumbo stars are no more than two million years old. They probably formed as we see them today.

What will happen next to the stars is a bit of a mystery, but theoretical models suggest that any merger will likely come quickly and quite explosively, releasing copious amounts of energy in the blast.

Astrophysicists believe that the merger of such close binary stars probably best explains how extremely massive stars are born. Astronomers have never witnessed such a merger, explaining their interest in MY Cam.

See for Yourself

MY Cam is nestled within a small open star cluster known as Alicante 1, which is located about 13,000 light-years from Earth. It is the brightest member of this sparsely populated stellar nursery filled with hot, young stars only a few million years old.

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This sky chart pinpoints the location of MY Cam as seen with the naked eye and with binoculars.


You can find MY Cam hiding out in the constellation Camelopardalis, the Giraffe, which is now visible throughout the Northern Hemisphere high in the northeastern evening sky. MY Cam sits at the end of the hind legs of the Giraffe, and its brightness appears to vary between 9.8 and 10.1 magnitude. That makes it just visible with binoculars but a fairly easy target for small backyard telescopes.

Happy hunting!

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