Skip to footer

Scientists directly observe planets being born

Lying some 450 light-years from Earth, dust around a young star called LkCa 15 is starting to gather into planets, say astronomers.

|
NASA/JPL-Caltech
Artist's illustration of planets forming in a circumstellar disk like the one surrounding the star LkCa 15. The planets within the disk's gap sweep up material that would have otherwise fallen onto the star.
|
by Steph Sallum. Gray-scale image generated from submillimeter data published in Isella et al., 2014.
Adaptive optics observations from the Large Binocular Telescope and the Magellan Adaptive Optics System (color scale) show multiple sources in the cleared region of the LkCa 15 transition disk (gray scale).

For the first time ever, astronomers have directly observed planets in the process of being born.

Scientists have photographed a gas-giant exoplanet forming around a young star called LkCa 15, which lies about 450 light-years from Earth.

"It's exciting, because it's the first time that we've been able to image forming planets directly," study lead author Stephanie Sallum, a graduate student at the University of Arizona, told Space.com. "It gives us a system to follow up in the future, in depth, to really understand the details of how planets form." [Gallery: The Strangest Alien Planets]

The LkCa 15 system features a large disk of dust and gas surrounding a sunlike star that's just 2 million years old. Such circumstellar disks commonly surround newborn stars, providing the raw materials from which planets form.

Indeed, previous studies have spotted large gaps in some disks that newly accreting alien worlds likely cleared out. Scientists have even detected disk asymmetries and heat signatures that have been interpreted as evidence of planets inside these gaps.

Such a gap exists in LkCa 15's disk, and one giant protoplanet candidate, known as LkCa 15b, was detected in the system in 2012, at a distance of about 16 astronomical units (AU) from the star. (One AU is the distance from Earth to the sun, about 93 million miles or 150 million kilometers.)

To learn more, Sallum and her colleagues zeroed in on the LkCA 15 system using the Large Binocular Telescope (LBT), an observatory in southeastern Arizona that boasts two 27-foot-wide (8.4 meters) primary mirrors.

The team confirmed the existence of LkCA 15b, imaging it directly in hydrogen-alpha photons, a type of light that's emitted when superheated material accretes onto a newly forming world. (Like newborn stars, newborn planets are surrounded by disks of feeder material.)

Other LBT observations revealed the presence of another newborn planet, LkCA 15c, inside the gap and suggested that a third (LkCA 15d) exists there as well, study team members report online today (Nov. 18) in the journal Nature.

"We're seeing sources in the clearing," Sallum said. "This is the first time that we've been able to connect a forming planet to a gap in a protoplanetary disk."

"The researchers' discovery provides stringent constraints on planet-formation theories," Zhaohuan Zhu of Princeton University, who was not affiliated with the new study, wrote in an accompanying "News & Views" piece in the same issue of Nature. "For example, such theories now have to explain how a giant planet can form 15-16 AU from its star within 2 million years, and still be growing after this time."

The new technique demonstrated by Sallum and her team could lead to the discovery of many other newly forming exoplanets, allowing astronomers to learn much more about the distribution of young worlds, Zhu added.

"Such an understanding of the young planet population will shed light on the decades-old problem of planet formation, and reveal how young planetary systems can evolve into older ones such as our solar system, billions of years after they were born," Zhu wrote.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook orGoogle+. Originally published on Space.com.

Copyright 2015 SPACE.com, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.
editor@csmonitor.com
Subscribe
Mark Sappenfield
Editor

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

Subscribe to insightful journalism

QR Code to Scientists directly observe planets being born
Read this article in
https://www.csmonitor.com/Science/2015/1119/Scientists-directly-observe-planets-being-born
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe