Youngest exoplanet captured
An artists impression of the planet LkCa 15b forming within the hole in the disk surrounding LkCa 15.
Art by Karen Teramura, UH IfA

Astronomers have revealed the first close-up images of a young planet in the process of formation in new research that aims to shed light on the ways in which planets and solar systems begin.

Dr. Michael Ireland of Macquarie University and Dr. Adam Kraus of the University of Hawaii’s Institute for Astronomy have published their discovery of the planet LkCa 15 b in the Astrophysical Journal. Dr Kraus will present their findings at NASA’s Goddard Space Flight Center meeting this week.

“LkCa 15 b is a gas giant, similar to Jupiter. There have been quite a few detections of Jupiter-like planets in recent years, but we’ve caught this one at the beginning of its life-cycle and orbiting a young, relatively nearby star. That’s something special to see,” said Dr. Ireland. 

Using the 10 meter Keck telescopes in Hawaii and a precision optical technique called aperture mask interferometry, the astronomers were able to capture the ground-breaking images.  

“We’ve been able to see, for the first time, a planet that is surrounded by dust and gas. This dusty matter is likely being deposited onto or ejected from the object,” said Dr. Ireland. “This kind of direct observation hasn’t been possible before as the light from the star is usually too bright to make accurate measurements. However, our technique enables us to account for the starlight so that we can still capture a high resolution image.”

Aperture mask interferometry involves placing a small mask consisting of 9 holes in the line of light collected from a star, which is then amplified by a giant telescope such as Keck in Hawaii. “We can then manipulate the light and cancel out distortions,” said Dr. Kraus. “It’s enabled us to see inside disks of dust and gas around young stars closer than ever before. The gaps in those disks are the perfect zone for young planets in the process of formation.”

Kraus and Ireland began searching for young planets through a survey of 150 young dusty stars in star forming regions, but refocused on a dozen stars as their search quickly yielded results. “LkCa 15 was only our second target, and we immediately knew we were seeing something new,” said Kraus.

“We knew it was more complex than a single companion object, so we collected data several times and at differing wavelengths over 12 months to get a clearer picture,” said Ireland. “What emerged is that we had indeed captured a young gas giant in the process of formation. Theorists have made guesses about what this might look like, but to finally see it is a real milestone.”

Dr’s Kraus and Ireland plan to continue their observations of nearby young stars in their efforts to construct a clearer picture of how planets and solar systems form. Of their future research, Ireland said, “studying systems like these can help us to understand more about our own solar system in relation to others out there. It’s one of those big questions – how unique are we really?”

For more images of LkCa 15b click here

Editor's Note: Original news release can be found here.