Click here to view Orion Nebula animations

Planetary Protection: X-Ray Super-Flares Aid Formation of "Solar Systems"

10 May 2005—Astronomers from Penn State lead the international research team that will announce on 10 May 2005 their new results from observations with NASA's Chandra X-ray Observatory, which imply that X-ray super-flares torched our young Solar System. Such flares likely affected the planet-forming disk around the early Sun, and may have enhanced the survival chances of Earth. "Big X-ray flares could lead to planetary systems like ours where Earth is a safe distance from the Sun," said Eric Feigelson of Penn State University in University Park, and principal investigator for the international Chandra Orion Ultradeep Project. "Stars with smaller flares, on the other hand, might end up with Earth-like planets plummeting into the star."

In addition to Feigelson, other Penn State scientists on the international team include Research Associate Kostantin Getman, Research Assistant Patrick Broos, Senior Research Associate Leisa Townsley, Visiting Fellow Masahiro Tsujimoto, and Evan Pugh Professor of Astronomy and Astrophysics Gordon Garmire.

By focusing on the Orion Nebula almost continuously for 13 days, the research team used Chandra to obtain the deepest X-ray observation ever taken of this or any star cluster. The Orion Nebula is the nearest rich stellar nursery, located just 1,500 light years away. These data provide an unparalleled view of 1400 young stars, 30 of which are prototypes of the early Sun. The scientists discovered that these young suns erupt in enormous flares that dwarf -- in energy, size, and frequency -- anything seen from the Sun today.

"We don't have a time machine to see how the young Sun behaved, but the next best thing is to observe Sun-like stars in Orion," said Scott Wolk of Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. "We are getting a unique look at stars between one and 10 million years old -- a time when planets form."

A key result is that the more violent stars produce flares that are a hundred times as energetic as the more docile ones. This difference may specifically affect the fate of planets that are relatively small and rocky, like the Earth.

According to recent theoretical work, X-ray flares can create turbulence when they strike planet-forming disks, and this affects the position of rocky planets as they form. Specifically, this turbulence can help prevent planets from rapidly migrating towards the young star. "Although these flares may be creating havoc in the disks, they ultimately could do more good than harm," said Feigelson. "These flares may be acting like a planetary protection program."

About half of the young suns in Orion show evidence for disks, likely sites for current planet formation, including four lying at the center of proto-planetary disks imaged by the Hubble Space Telescope. X-ray flares bombard these planet-forming disks, likely giving them an electric charge. This charge, combined with motion of the disk and the effects of magnetic fields, should create turbulence in the disk.

The numerous results from the Chandra Orion Ultradeep Project will appear in a dedicated issue of The Astrophysical Journal Supplement during 2005. The team contains 37 scientists from institutions across the world including the US, Italy, France, Germany, Taiwan, Japan and the Netherlands.

To make their observations, the researchers used Chandra's ACIS X-ray camera, which was conceived and developed for NASA by Penn State and the Massachusetts Institute of Technology under the leadership of Gordon Garmire, Evan Pugh Professor of Astronomy and Astrophysics at Penn State. NASA's Marshall Space Flight Center, Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington, D.C. Northrop Grumman of Redondo Beach, California, was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Massachusetts.

ADDITIONAL INFORMATION AND IMAGES:
At Chandra: http://chandra.harvard.edu
At NASA: http://chandra.nasa.gov
Chandra Orion Ultradeep Science page: http://www.astro.psu.edu/coup

SCIENCE CONTACTS:
Scott Wolk, swolk@cfa.harvard.edu, 617-496-7766
Eric Feigelson, edf@astro.psu.edu, 814-865-0162

PIO CONTACTS:
Megan Watzke, Chandra X-ray Center, mwatzke@cfa.harvard.edu, 617-496-7998
Barbara K. Kennedy, Penn State, science@psu.edu, 814-863-4682

[ M. W. / B. K. K. ]

Orion Nebula Animations
	A Multiwavelength Look At Orion [Runtime: 0:20]
	Quicktime High Resolution (13.7 MB) Low Resolution (2.9 MB)	MPEG High Resolution (3.9 MB) Low Resolution (2.9 MB)
This sequence begins with Chandra's image of the Orion Nebula Cluster, the deepest X-ray image ever obtained of a star cluster. The image contains over 1,600 X-ray sources, most of them young stars. Zooming into a smaller region at the cluster's center, the view then dissolves to an optical image from the Hubble Space Telescope of the same region, followed by an infrared image made by ESO's Very Large Telescope, before returning to the Chandra data.
(Credit: X-ray: NASA/CXC/Penn State/E.Feigelson & K.Getman et al. Optical: NASA/STScI/Rice University/C.O'Dell et al. Infrared: ESO/VLT/M.McCaughrean et al.)
Field Guide: Normal Stars & Star Clusters

Animation of X-ray Flares from a "Young Sun" [Runtime: 0:23]
Quicktime High Res (15.6 MB) Low Res (2.6 MB)	MPEG High Res (4.4 MB) Low Res (3.3 MB)
This animation shows how X-ray flares from a young star affect a planet-forming disk. Light from the young star is reflected off the inner part of the disk, making it glow. The view zooms in to show small white flares continually erupting on the surface of the young star. A set of huge white magnetic loops then erupts from the star and hits the inside edge of the disk, resulting in an extremely bright flare. X-rays from the flare then heat up the planet-forming disk and will later result in turbulence that affects the positions of planets.
(Animation: NASA/CXC/A.Hobart)
View Still Images

	Time-Lapse Movie of Chandra Observations [Runtime: 0:16]
	Quicktime High Res (7.6 MB) Low Res (1.3 MB)	MPEG High Res (3.3 MB) Low Res (2.4 MB)
Zooming in from the full X-ray image, this sequence shows a time-lapse movie of Chandra data covering a smaller region of the Orion Nebula. Rapid variations in the young Orion stars can be seen during this 7-day-long observation (half the full Chandra observation) which contains 50 X-ray images. The star at the center of the image shows the strongest flare recorded among 30 stars with masses close to that of the Sun. This flare is about 10,000 times more powerful than the biggest flares seen on the Sun. If the Sun were placed at the distance of the Orion Nebula, its largest flares would not be visible in this movie.
(Credit: NASA/CXC/Penn State/E.Feigelson & K.Getman et al.)