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Spitzer finds peek-a-boo stars playing hula hoop

Jenny Winder, News Writer
Aug 3, 2013, 7:00 UTC

Sen—Astronomers using NASA's Spitzer Space Telescope have spotted a young stellar system that "blinks" every 93 days.

The system, called YLW 16A, likely consists of three developing stars, two of which are surrounded by a disk of material left over from the star-formation process.

As the two inner stars whirl around each other, they periodically peek out from the disk that girds them like a hula hoop. The hoop itself appears to be misaligned from the central star pair, probably due to the disrupting gravitational influence of the third star orbiting the edge of the system. The whole system cycles through bright and faint phases, with the central stars playing cosmic peek-a-boo as the tilted disk twirls around them. It is believed that this disk should go on to spawn planets and the other celestial bodies that make up a solar system.

Spitzer, an 85 cm diameter telescope designed to detect infrared radiation, was launched into an Earth-trailing, heliocentric orbit back in August 2003. It is the fourth and final observatory under NASA's Great Observatories program, which also includes the Hubble Space Telescope, Chandra X-Ray Observatory and Compton Gamma Ray Observatory. It is also the first new mission under NASA's Origins program, which seeks to answer the questions: Where did we come from? Are we alone?

Artist's impression of the Spitzer Space Telescope. Image credit: NASA/JPL-Caltech/R. Hurt (SSC)

Astronomers using Spitzer observed infrared light from YLW 16A, emitted by the warmed gas and dust in the disk that swathes the young stars. Other observations came from the ground-based 2MASS survey, as well as from the NACO instrument at the European Southern Observatory's Very Large Telescope in Chile.

YLW 16A is the fourth example of a star system known to blink in such a manner, and the second in the same star-forming region Rho Ophiuchus, suggesting that these systems might be more common than once thought.

Blinking star systems with warped disks offer scientists a way to study how planets form in these environments. The planets can orbit one or both of the stars in the binary star system. Such worlds are referred to as circumbinary planets. Astronomers can record how light is absorbed by planet-forming disks during the bright and faint phases of blinking stellar systems, which reveals information about the materials that comprise the disk.

"These blinking systems offer natural probes of the binary and circumbinary planet formation process," said Peter Plavchan, a scientist at the NASA Exoplanet Science Institute and Infrared Processing and Analysis Center at the California Institute of Technology, and lead author of a new paper accepted for publication in Astronomy & Astrophysics.