Category Archives: Gemini Observatory

Gemini Observatory, impacts, planetary science

Jupiter’s Southern “Bruise”

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As Seen by Gemini Observatory

The impact site of Jupiter, as seen by Gemini Observatory. It looks similar to the Shoemaker-Levy 9 crash sites that appeared in 1994 after the impact of that comet with Jupiters cloud tops.
The impact site of Jupiter, as seen by Gemini Observatory. It looks similar to the Shoemaker-Levy 9 crash sites that appeared in 1994 after the impact of that comet with Jupiter's cloud tops. (Click to embiggen.)

As more observatories turn their attention to the bruise at Jupiter’s southern polar region, the images just keep getting better.  Today’s release from Gemini Observatory on Mauna Kea in Hawai’i shows a composite mid-infrared view of the impact site (the bright yellow pair of blobs at the bottom center of the image at left).

This is looking more and more like the SL-9 crash effects from 1994, a point that SL-9 veteran Heidi Hammel pointed out as she described what they see in the images. “The morphology is suggestive of an arc-like structure in the feature’s debris field,” she added.

The mid-infrared wavelength image is showing the effect of scattered material as a result of this most recent impact.  It’s likely that the impactor was a small (hundreds of meters across) comet or asteroid — not something that could have been seen from Earth even with powerful telescopes.

The Gemini images that  made up the composite were obtained with the MICHELLE spectrograph/imager. This gave a series of images at seven 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 this 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 so that they can understand just what it was that plowed into Jupiter and what chemical elements it contained. 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.

This image is one of those “target of opportunity” sets that observatories plan for when they allocate time each year. Essentially, the planning committees put aside time “just in case” something happens — just like it did with this impactor at Jupiter. As scientist Imke de Pater noted, “the Gemini support staff made a heroic effort to get these data.”  The Gemini team (Tom Geballe, Chad Trujillo, Rachel Mason and Paul Hirst, aided by Glenn Orton and Leigh Fletcher (of JPL)) swung into action immediately, making the telescope available within 24 hours of the request for observing time. It’s important to get data as soon as possible during these types of events, which are “transient” — meaning that they and their effects don’t last long, and the evidence for whatever the impactor was gets dissipated pretty quickly.  For more details on this Gemini image, swing your attention to the impact’s image page at Gemini’s website.

Update:  I heard that HST has also looked at this site as a target of opportunity. Not sure exactly when in the next day or so the image(s) will be available, but whatever shows up should be spectacular!

astronomy news, extrasolar planets, Gemini Observatory

First Picture of a Planet around a Sun-like Star

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Gemini Observatory Image Shows Possible Extrasolar Planet

1RSX J160929.1-210524 and its likely ~8 Jupiter-mass companion (in red circle)
1RSX J160929.1-210524 and its likely ~8 Jupiter-mass companion (in red circle) The suspected planet has an estimated temperature of about 1800 Kelvin (about 1500ºC), much hotter than our own Jupiter, which has a temperature of about 160 Kelvin (-110ºC). Its likely host is a young star of type K7 with an estimated mass about 85% that of the Sun.

So, there I was on Friday night, playing with a computer game when I got a call from the Public Information Office at Gemini Observatory. I do some editing and writing for them from time to time, and since they’re six hours behind me (time-zone-wise) a late Friday call is not exactly a surprise. But, what Peter Michaud (their PIO) told me next was big news: that Gemini had likely bagged the first known image of a planet orbiting another star similar to the Sun. Not only that, but it is a HUGE planet (8 Jupiter masses) and orbits more than three hundred times the Earth-Sun distance from its own parent star.

This, as you might expect if you follow extrasolar planet searches, is big news. Nobody has directly imaged an actual planet around a normal star like the Sun before. Stars are too bright and planets are usually too small to be seen in the glare of the nearby star.  So far, planet discoveries have been made using several indirect methods, such as the Doppler detection technique (which measures the Doppler shift in starlight that occurs as a star and its planet(s) orbit around a common center of mass) about which you can read more here.

So, as you can imagine, an actual image of an extrasolar planet is pretty exciting; so much so that when the team of astronomers at the University of Toronto that did the work posted a pre-print paper about their finding, people took immediate notice. Gemini Observatory then worked up a press release (that a number of us then finessed over the weekend) and it came out early today. I expect this news will generate a lot of excitement and discussion in planetary-search circles.

The suspected star-planet combo (which lies about 500 light-years from Earth) was found as part of a survey of over 85 stars in the Upper Scorpius association, a group of young stars formed about 5 million years ago.

“This is the first time we have directly seen a planetary mass object in a likely orbit around a star like our Sun,” said David Lafrenière, lead author of a paper submitted to the Astrophysical Journal Letters and also posted online. “If we confirm that this object is indeed gravitationally tied to the star, it will be a major step forward.”

The near-infrared images and spectra of this suspected planetary object indicate that it is too cool to be a star or even a more massive brown dwarf, and that it is very young. Spectra indicate that it is the same distance from Earth as its star. It will probably take the better part of two years to absolutely confirm that this planet is definitely orbiting that star, but the science team making the discovery points to this data as very compelling evidence to prove that it is.

The team’s Gemini observations took advantage of adaptive optics technology to dramatically reduce distortions caused by turbulence in Earth’s atmosphere so they could make out the object, which appears to be orbiting its primary star at a distance of about 330 astronomical units.  To put this in comparison to our own solar system, Neptune orbits the Sun at about 40 AU, Pluto is at 39.4 AU.