A series of images taken between November 2013 to
April 2015 with the Gemini Planet Imager (GPI) on the Gemini South
telescope in Chile shows the exoplanet β Pic b orbiting the star β
Pictoris, which lies over 60 light-years from Earth. In the images, the
star is at the centre of the left-hand edge of the frame; it is hidden
by the Gemini Planet Imager’s coronagraph. We are looking at the
planet’s orbit almost edge-on; the planet is closer to the Earth than
the star. The images are based on observations described in a paper
published in the Astrophysical Journal, 16 September 2015 and whose lead
author is Maxwell Millar-Blanchaer. GPI is a groundbreaking instrument
that was developed by an international team led by Stanford University’s
Prof. Bruce Macintosh (a U of T alumnus) and the University of
California Berkeley’s Prof. James Graham (former director of the Dunlap
Institute for Astronomy & Astrophysics, U of T). Image credit: M.
Millar-Blanchaer, University of Toronto; F. Marchis, SETI Institute. Vimeo
GIF version of animation.
Image credit: M. Millar-Blanchaer, University of Toronto; R. Marchis (SETI Institute)
A team of astronomers has given us our best view yet of an exoplanet moving in its orbit around a distant star. A series of images captured between November 2013 to April 2015 shows the exoplanet β Pic b as it moves through 1 ½ years of its 22-year orbital period.
First discovered in 2008, β Pic b is a gas giant planet ten to twelve
times the mass of Jupiter, with an orbit roughly the diameter of
Saturn’s. It is part of a dynamic and complex system that includes
comets, orbiting gas clouds, and an enormous debris disk that in our
Solar System would extend from Neptune’s orbit to nearly two thousand
times the Sun/Earth distance. Because the planet and debris disk
interact gravitationally, the system provides astronomers with an ideal
laboratory to test theories on the formation of planetary systems beyond
ours.
Maxwell Millar-Blanchaer, a PhD-candidate in the Department of Astronomy
& Astrophysics, University of Toronto, is lead author of a paper to
be published September 16th in the Astrophysical Journal. The paper
describes observations of the β Pictoris system made with the Gemini
Planet Imager (GPI) instrument on the Gemini South telescope in Chile.
"The images in the series represent the most accurate measurements of
the planet’s position ever made," says Millar-Blanchaer. "In addition,
with GPI, we're able to see both the disk and the planet at the exact
same time. With our combined knowledge of the disk and the planet we’re
really able to get a sense of the planetary system’s architecture and
how everything interacts."
The paper includes refinements to measurements of the exoplanet’s orbit
and the ring of material circling the star which shed light on the
dynamic relationship between the two. It also includes the most accurate
measurement of the mass of β Pictoris to date and shows it is very
unlikely that β Pic b will pass directly between us and its parent star.
"It’s remarkable that Gemini is not only able to directly image
exoplanets but is also capable of effectively making movies of them
orbiting their parent star," said Chris Davis, astronomy division
program director at the National Science Foundation, which is one of
five international partners that funds the Gemini twin telescopes’
operation and maintenance. "Beta Pic is a special target. The disk of
gas and dust from which planets are currently forming was one of the
first to be observed and is a fabulous laboratory for the study of young
solar systems.”
Astronomers have discovered nearly two thousand exoplanets in the past
two decades but most have been detected with instruments – like the
Kepler space telescope – that use the transit method of detection:
astronomers detect a faint drop in a star’s brightness as an exoplanet
transits or passes between us and the star, but do not see the exoplanet
itself.
With GPI, astronomers image the actual planet – a remarkable feat given
that an orbiting world typically appears a million times fainter than
its parent star. This is possible because GPI's adaptive optics sharpen
the image of the target star by cancelling out the distortion caused by
the Earth’s atmosphere; it then blocks the bright image of the star with
a device called a coronagraph, revealing the exoplanet.
Laurent Pueyo is with the Space Telescope Science Institute and a co-author on the paper. "It’s fortunate that we caught β Pic b just as it was heading back – as seen from our vantage point – toward β Pictoris," says Pueyo. "This means we can make more observations before it gets too close to its parent star and that will allow us to measure its orbit even more precisely."
GPI is a groundbreaking instrument that was developed by an
international team led by Stanford University’s Prof. Bruce Macintosh (a
U of T alumnus) and the University of California Berkeley’s Prof. James
Graham (former director of the Dunlap Institute for Astronomy &
Astrophysics, University of Toronto).
In August 2015, the team announced its first exoplanet discovery: a
young Jupiter-like exoplanet designated 51 Eri b. It is the first
exoplanet to be discovered as part of the GPI Exoplanet Survey (GPIES)
which will target 600 stars over the next three years.
Contact:
Media Contact:
Peter Michaud
Public Information and Outreach ManagerGemini Observatory, Hilo, HI
Email: pmichaud@gemini.edu
Cell: (808) 936-6643
Desk: (808) 974-2510
Chris Sasaki
Communications Coordinator
Dunlap Institute for Astronomy & Astrophysics
University of Toronto
Email: media@dunlap.utoronto.ca
Phone: 416-978-6613
Science Contacts:
Max Millar-Blanchaer
Department of Astronomy and Astrophysics
University of Toronto
Email: maxmb@astro.utoronto.ca
Phone: (416) 978-3146
Fredrik Rantakyro
Gemini Observatory, La Serena, Chile
Email: frantaky@gemini.edu
Cell: 9 - 995097802
Desk: 56-51- 2205665
Joint University of Toronto and Gemini Observatory Press Release
See the Dunlop Observatory/University of Toronto version of this release here.
Source: Gemini Observatory
