Jupiter is sporting a glowing bruise after getting unexpectedly whacked by a
small solar system object, according to astronomers using the Gemini North
telescope on Mauna Kea in Hawai'i. A spectacular new mid-infrared image is
available for download.
The new feature on Jupiter was first seen by Australian amateur astronomer
Anthony Wesley on July 19th. The object that caused the impact scar could
have been a small comet or asteroid. Using the SL9 impacts as a guide, the
impacting object was probably just a few hundreds of meters in diameter.
Such small bodies are nearly impossible to detect near or beyond Jupiter
unless they reveal cometary activity, or, as in this case, make their
presence known by impacting a giant planet. The impact site is dark in
visible-wavelength images.
With the superb angular resolution of the Gemini observations, the data show
the impact site in remarkable detail. "The structure of the impact site is
eerily reminiscent of the larger Shoemaker-Levy 9 sites 15 years ago,"
remarked Heidi Hammel (Space Science Institute), who was part of the team
that supported the effort at Gemini. In 1994, Hammel led the Hubble Space
Telescope team that imaged Jupiter when it was pummeled by a shattered
comet. "The morphology is suggestive of an arc-like structure in the
feature's debris field," Hammel noted.
"We utilized the powerful mid-infrared capabilities of the Gemini telescope
to record the impact's effect on Jupiter's upper atmosphere," said Imke de
Pater (University of California, Berkeley). "At these wavelengths we receive
thermal radiation (heat) from the planet's upper atmosphere. The impact site
is clearly much warmer than its surroundings, as shown by our image taken at
an infrared wavelength of 18 microns."
The Gemini images were obtained with the MICHELLE spectrograph/imager,
yielding a series of images at 7 different mid-infrared wavelengths. Two of
the images (8.7 and 9.7 microns) were combined into a color composite image
by Travis Rector at the University of Alaska, Anchorage to create the final
false-color image. By using the full set of Gemini images taken over a range
of wavelengths from 8 to 18 microns, the team will be able to disentangle
the effects of temperature, ammonia abundance, and upper atmospheric aerosol
content. Comparing these Gemini observations with past and future images
will permit the team to study the evolution of features as Jupiter's strong
winds disperse them.
"The Gemini support staff made a heroic effort to get these data," said de
Pater. "We were on the telescope observing within 24 hours of contacting the
observatory." Because of the transient nature of this event, the telescope
was scheduled as a "Target of Opportunity" and required staff to react
quickly to the request. Tom Geballe and Chad Trujillo helped plan the
observations, Rachel Mason programmed the observing plan for MICHELLE and
the telescope, and Paul Hirst performed the observations. Additional members
of the team are Glenn Orton and Leigh Fletcher from the Jet Propulsion
Laboratory.
The Gemini Observatory is operated by the Association of Universities for
Research in Astronomy, Inc., under a cooperative agreement with the NSF on
behalf of the Gemini partnership: the National Science Foundation (United
States), the Science and Technology Facilities Council (United Kingdom), the
National Research Council (Canada), CONICYT (Chile), the Australian Research
Council (Australia), Ministio da Cicia e Tecnologia (Brazil), and SECYT
(Argentina)
IMAGE CAPTION:
[JPEG:
http://www.gemini.edu/images/stories/press_release/pr2009-3/fig1_hi.jpg
(55KB)
TIFF: http://www.gemini.edu/images/stories/press_release/pr2009-3/fig1.tif
(1.1MB)]
This mid-infrared composite image was obtained with the Gemini North
telescope on Mauna Kea, Hawai'i, on 22 July at ~13:30 UT with the MICHELLE
mid-infrared spectrograph/imager. The impact site is the bright yellow spot
at the center bottom of Jupiter's disk. The image was constructed from two
images: one at 8.7 micron (blue) and one at 9.7 micron (yellow). The
excellent quality of the Gemini images reveals that the morphology of this
new impact bears a striking resemblance to that of the larger impact sites
seen after the comet Shoemaker-Levy 9 crashed into Jupiter in 1994.
Gemini Observatory
Hilo, Hawaii
Contacts:
Peter Michaud
Gemini Observatory, Hilo Hawaii
(808) 974-2510 (Desk)
Robert Sanders
Manager, Science Communications
UC Berkeley
(510) 643-6998
Imke de Pater
UC Berkeley
(510) 643-6998
Heidi B. Hammel
Space Science Institute, Boulder, CO
(720) 974-5888
For Immediate Release: July 23, 2009
