HD Picture:Hubble Finds Hidden Exoplanet in Archival Data torrent

In 19 years of observations, the Hubble Space Telescope has amassed a huge archive of data. That archive may contain the telltale glow of undiscovered extrasolar planets, says David Lafrenière of the University of Toronto, Ontario, Canada. His team found the outermost of three massive planets known to orbit the young star HR 8799, which is 130 light-years away. The planetary trio was originally discovered in images taken with the Keck and Gemini North telescopes in 2007 and 2008. But using a new image processing technique that suppresses the glare of the parent star, Lafrenière found the telltale glow of the outermost planet in the system while studying Hubble archival data taken in 1998. The giant planet is young and hot, but still only 1/100,000th the brightness of its parent star (by comparison, cooler Jupiter is one-billionth the brightness of the sun).

Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has looked at over 200 other stars in coronagraphic mode, where the light of the star is largely blocked out, to search for the feeble glow of planets. Lafrenière plans to look for undiscovered planets in the NICMOS archive dataset and do follow-up observations with ground-based telescopes on any candidates that pop up. As an added bonus, NICMOS made a near-infrared measurement that suggests water vapor is in the atmosphere of the planet. This could not be easily achieved with ground-based telescopes, because water vapor in Earth's atmosphere absorbs some infrared wavelengths. Measuring the water absorption properties on this exoplanet will tell astronomers a great deal about the temperatures and pressures in the atmosphere, and about the prevalence of dust clouds. But don't go looking for beachfront property; the planet is 1,500 degrees Fahrenheit -- too hot even for water vapor clouds.


About the Object
Object Name: HR 8799b
Object Description: Extrasolar Planet Orbiting Star HR 8799
Position (J2000): R.A. 23h 07m 28s.71
Dec. +21° 08' 03".30
Constellation: Pegasus
Distance: 130 light-years or 39 parsecs away

About the Data
Data Description:

The Hubble data is from proposal 7226: E. Becklin (University of California, Los Angeles), D. Kirkpatrick and P. Lowrance (California Institute of Technology), B. Zuckerman (University of California, Los Angeles), G. Schneider and D. McCarthy (University of Arizona), T. Henry (Georgia State University Research Foundation), R. Terrile (Jet Propulsion Laboratory), D. Koerner (University of Pennsylvania), and B. Smith (University of Hawaii).

The science team comprises: D. Lafrenière (University of Toronto, Canada), C. Marios (Herzberg Institute of Astrophysics, BC), R. Doyon (University of Montreal), and T. Barman (Lowell Observatory).

Instrument: NICMOS
Exposure Date(s): October 30, 1998
Filters: F160W (H band)

About the Release
Image Credit: NASA, ESA, and D. Lafrenière (University of Toronto, Canada)
Release Date: April 1, 2009