protoplanetary disk around J 1604
February 8, 2013

First Infrared Image Of Planet Forming Inside Disk

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Lee Rannals for - Your Universe Online

The Subaru Telescope has helped astronomers capture the first vivid infrared image of a distant planet forming from a young star.

Astronomers wrote in Astrophysical Journal Letters about an image of a curved arm of dust extending over a hole on a disk, which is a feature that could provide evidence that there are planets found within the hole.

The young star--2MASS J16042165-2130284, or J 1604, hosts a dynamic environment in which planets may be born, and the latest image provides astronomers with information about constraints on the distance at which they form.

For the past 20 years, researchers confirmed that new stars are surrounded by disks of dense gas and dust, or protoplanetary disk, in which planets begin to take shape. Once a star enters an active phase of planet building, newborn planets may deplete some of the gas and dust in the disk to produce a hole within it.

This is the first time researchers have been able to provide direct imaging of the planet building process inside the hole, by using the high-resolution infrared camera HiCIAO, or High Contrast Instrument for the Subaru Next Generation Adaptive Optics, on the Subaru Telescope.

J 1604 has a similar mass to the Sun's, and is located in the Upper Scorpius star-forming region about 470 light years away. Astronomers believe the star is merely 3.7 million years old.

The team was able to use HiCIAO to capture a very high-resolution near-infrared image of its protoplanetary disk, which shows dust particles that scatter light from the central star. The disk features a large hole with an asymmetric dip, and a survey arm extending over the hole.

This is the first vivid infrared image of an arm in the disks around young stars, and could also be the first detection of an arm of dust that leads to planet formation of a rocky-planet. The astronomers believe the surface brightness of the gap show that it drops by a factor of five, when compared to the rest of the disk.

They wrote that the characteristics of the hole in the disk, and the arm over it, indicate the possible presence of unseen planets within the hole, and their calculations suggest that the hole might mark the presence of at least one planet.

The researchers concluded that unseen planets could explain its structure, and that overall, these findings identify constraints on planet formation at certain distances from the central star.

Finding exoplanets is becoming more exciting as new methods and observations unveil the curtain of a star's light, to determine what surrounds it. NASA's James Webb Space Telescope will be helping to provide a new outlook in the hunt for these exoplanets.

"If there are other planets in the Alpha Centauri system farther from the star, JWST may be able to detect them as well through imaging,” said Grunsfeld, according to an October redOrbit report.

NIRISS, an instrument that will be aboard the telescope, will help to study Earth-sized exoplanets, as well as the most distant galaxies. This instrument has specifically been designed to detect the atmosphere of Earth-sized exoplanets, and could also help determine the composition of these atmospheres, such as whether they contain water vapor and carbon dioxide.

Image 2 (below): Subaru Telescope's near-infrared (1.6 μm) image of the protoplanetary disk around the young star J 1604. A black circular mask covers the bright, saturated light from the central star. The gauges for distance are in astronomical units and arc seconds. (Abbreviated as AU, an astronomical unit is the distance between the Sun and Earth. Abbreviated as arcsec, an arc second is 1/3600 of a degree.) Prominent features include the hole (white dotted line) in the disk; the arm extending over the hole (on the right); and the asymmetric dip (on the left). Credit: The Graduate University for Advanced Studies and the National Astronomical Observatory of Japan