Largest data on brightening and dimming of 200,000,000 stars released

Astronomers have released the largest data set ever collected that documents the brightening and dimming of two hundred million of stars and other celestial objects.

Studying the phenomena of celestial objects can help astronomers better understand the evolution of stars, massive black holes in the centers of galaxies, and the structure of the Milky Way.

These types of objects were also essential for the recent discovery of dark energy - the mysterious energy that dominates the expansion of the universe - which earned a Nobel Prize in 2011.

Using the Catalina Real-Time Transient Survey (CRTS), a project led by Caltech, astronomers from the California Institute of Technology (Caltech) and the University of Arizona systematically scanned the heavens for these dynamic objects, producing an unprecedented data set that will allow scientists worldwide to pursue new research.

“Exploring variable objects and transient phenomena like stellar explosions is one of the most vibrant and growing research areas in astrophysics,” S George Djorgovski, professor of astronomy at Caltech and principal investigator on the CRTS, said.

“In many cases, this yields unique information needed to understand these objects,” Djorgovski said.

The observations were part of the Catalina Sky Survey (CSS), a search for Near-Earth Objects (NEOs) - asteroids that may pose a threat to Earth -conducted by astronomers at the University of Arizona.

By repeatedly taking pictures of large swaths of the sky and comparing these images to previous ones, the CRTS is able to monitor the brightness of about half a billion objects, allowing it to search for those that dramatically brighten or dim.

In this way, the CRTS team identified tens of thousands of variables, maximizing the science that can be gleaned from the original data.

The new data set contains the so-called brightness histories of a total of two hundred million stars and other objects, incorporating over 20 billion independent measurements.

“This set of objects is an order of magnitude larger than the largest previously available data sets of their kind,” said Andrew Drake, a staff scientist at Caltech.

“It will enable many interesting studies by the entire astronomical community,” he said.

The data will be presented at the meeting of the American Astronomical Society in Austin on January 12.