Citizen Sky

[RJN]

http://www.citizensky.org/content/about-citizen-sky

Citizen Sky is a citizen science project providing you with a chance to do real scientific research. We are seeking to understand a star that has been a mystery to scientists for many years. This star is epsilon Aurigae, a very interesting, very bright star located in the constellation Auriga, the charioteer. This star is bright enough to be seen with the unaided eye even in the most light-polluted cities, and it is visible every fall, winter, and spring.

[bystander]

A distant eclipse glimpsed
Nature Editor's Summary - 2010 Apr 8

Every 27.1 years the bright binary star ϵ Aurigae dims as it undergoes an eclipse lasting about 18 months. Until now the body that transits the disk of the ϵ Aur system has been undetectable and the subject of much speculation. The preferred explanation is that the invisible companion is a tilted disk of opaque material surrounding a hidden star. Recent work implies that the system consists of a visible F-star, paired with a single B5V star enshrouded by a disk at a temperature of about 500K. Now interferometric observations made with the six-telescope CHARA Array in November and December 2009 have produced images of the eclipsing body in the infrared, revealing it to be an opaque disk, its elliptical shape suggesting that it is tilting as predicted.

Stellar astrophysics: Shrouded in a dusty disk

• Nature 464, 842-843 (8 April 2010) | doi: 10.1038/464842a;

For more than a century, the binary star system ϵ Aurigae has been a riddle, wrapped in a mystery, inside an enigma. But no more — the system's previously inferred but unseen disk of dust has been detected.

Infrared images of the transiting disk in the ϵ Aurigae system

• Nature 464, 870-872 (8 April 2010) | doi: 10.1038/nature08968

Click to play embedded YouTube video.

Astronomers take close-up pictures of mysterious dark object
EurekAlert: University of Michigan: 2010 Apr 07

For the first time, astronomers have directly observed the mysterious dark companion in a binary star system that has puzzled skywatchers since the 19th century.

Using an instrument developed at the University of Michigan, scientists have taken close-up pictures of Epsilon Aurigae during its eclipse, which happens every 27 years. "Close up" in this case is a relative term, but the images zoom in enough to show the shape of the dark object's shadow.

Astronomers Capture a Rare Stellar Eclipse in Opening Scene of Year-long Show
National Science Foundation 10-056 - 2010 Apr 07

Ground-based CHARA Array enables unprecedented images of a double star system some 2,000 light years from Earth.

For the first time, a team of astronomers has imaged the eclipse of the star Epsilon Aurigae by its mysterious, less luminous companion star. Very high-resolution images, never before possible, have been published online today in the journal Nature Letters. Epsilon Aurigae has been known since 1821 as an eclipsing double star system, but astronomers have struggled for many decades trying to decipher the clues to what was causing these eclipses, which happen every 27 years. The new image largely settles the matter: the eclipse is caused by a disk of material, probably similar to the state of our solar system 4.5 billion years ago as the planets began to form around our own infant sun.

Secrets of Shady Star System Revealed
Space.com - 2010 Apr 07

New images of two strange stars, where one passes in front of the other to block its light periodically as seen from Earth, are beginning to give up the secrets of this puzzling stellar pair.

The star system, called Epsilon Aurigae, experiences the eclipse once every 27 years. For the first time, scientists have directly imaged the dark companion that blocks its companion's light.

Astronomers have been watching this pair of stars since the 1800s. Over time, they noticed that the main star appears dimmer than it should be, given its mass, and that its brightness dips even more for longer than a year every few decades. The system lies about 2,000 light-years from Earth (a light-year is the distance light can travel in one year).

Scientists had previously surmised that the bright star has a hidden companion that was blocking its light, and the new observations confirm that.

Scientists capture 'terrifying' Tolkien-like eclipse
Phys.org Astronomy - 2010 Apr 07

Scientists have captured a 'terrifying' image of a giant Goliath-like star undergoing a two year eclipse. First discovered by a German astronomer 180 years ago, it is the first close-up image of an eclipse beyond the solar system to be captured on camera by scientists.