Record-Setting Eclipse Discovered With Help From Some Very Old Photos

Total solar eclipses are short-lived events, lasting only a matter of minutes. Eclipses of other stars in our galaxy — so-called stellar eclipses — can last a bit longer.

How much longer? A team of astronomers just discovered a binary star system in which one red giant star orbiting another eclipses it for a remarkable three and a half years.

That makes this the longest-lasting stellar eclipse ever observed.

Known only as TYC 2505-672-1 the system, the discovery of which is in a paper that was accepted last month for publication in Astronomical Journal, also has the longest period between eclipses ever seen. Sixty-nine years pass between one eclipse and the next.

The system, located in the constellation Leo Minor, eclipsed during World War II and again from 2011 through 2014, New Scientist reported. The next won’t come until April of 2080.

It’s easy enough to understand solar eclipses, in which light from the sun is blocked as the moon passes between it and the Earth. Ditto for lunar eclipses, in which the moon appears to dim as it passes through the Earth’s shadow.

But how can one star blot out another if both emit light?

The team, led by astronomers from Vanderbilt and Harvard, believe it’s because one of the stars in the system is encased in a cloud of dust and gas so thick that it blocks light.

“About the only way to get these really long eclipse times is with an extended disk of opaque material,” Joseph Rodriguez, an astronomy graduate student at Vanderbilt University and the first author of a paper about the discovery, said in a written statement. “Nothing else is big enough to block out a star for months at a time.”

(Story continues below graph.)

The stars in the system orbit —> Read More