Zooming in on a nearby young star called HD 141569A, astronomers from the National Astronomical Observatory of Japan and the Max Planck Institute for Astronomy used the Subaru telescope on Mauna Kea, Hawai'i, to discover a hole in a disk of gas and dust encircling the star. The existence of this large gap, which is about the size of the orbit of Saturn, supports the theory that this young star ended its infancy abruptly, by ionizing and pushing away the gas in the disk from which it was born.
The team, lead by Dr. Miwa Goto and Professor Tomonori Usuda took advantage of the superb spatial resolution attained by the adaptive optics system and the infrared camera and spectrograph (IRCS) on Subaru, to resolve the innermost part of the disk around HD 141569A in emission lines of carbon monoxide in the infrared part of the electromagnetic spectrum.
The disk was known to exist from previous studies of the dust around the star. By studying the gas, the new study successfully determined the size of the inner clearing in the disk.
Emission from carbon monoxide (CO) in the disk surrounding HD 141569A, which lies some 320 light-years away from Earth, extends out to a distance fifty times the size of the orbit of Earth. (The distance between Earth and the Sun is called an astronomical unit. In our solar system, the orbital radius of Neptune is about 30 AU).
It gradually becomes stronger toward the inner part closest to the star. The emission peaks at around 15 AU, then diminishes to the central star. "We now know that little gas remains in the inner 11 AU of the disk," said Usuda. "In other words, HD 141569A has fully developed a hole at the center of its molecular gas disk bigger than the size of the orbit of Saturn."
"The size of the hole is very significant", said Goto, "because it limits the possibilities of how the hole came to be in the first place."
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