Friday, 17 March 2017

TEXES on Gemini North: Blazing Jupiter!

All of this week the TEXES team has been out on Mauna Kea running a programme of observations that included ten hours of time scanning Jupiter's tropics.  I proposed this to solve a key issue that we have - TEXES has provided fantastic spectral maps from the IRTF but with a limited spatial resolution from the 3-m primary mirror, whereas VISIR on the VLT (among others) provides superb imaging at high spatial resolution, but without decent spectroscopy.  By moving TEXES to Gemini-North for this special run, we were able to get the best of both worlds.

Sadly neither I nor the Leicester team could join them this time, but Tommy Greathouse, Glenn Orton, James Sinclair and Rohini Giles were sending me nearly continuous updates, and provided the data in a raw form on Tuesday morning.  I processed the spectral data into a map at just one wavelength (1165 cm-1, which senses deep temperatures and jovian aerosols, and always contains a lot of structure) to share in the Gemini e-cast.  There's also a nifty 3-colour image, generated from three wavelengths in the same spectral setting, which we'll be using in a future GeminiFocus magazine.  Needless to say, we're all pretty delighted with these data - the highest spatial-resolution spectral map of Jupiter ever acquired, period.  This is going to keep us going for years.

TEXES Gemini and Jupiter:

To truly understand the atmospheric phenomena at work in Jupiter, we must investigate three different domains - spatial, temporal, and spectral.  Past investigations have allowed us to target one of these domains, but today we are able to explore all three by combining the Gemini observatory, the TEXES spectrograph and the worldwide campaign of Earth-based support for NASA’s Juno mission.  This three-colour map reveals Jupiter’s weather layer near 8.6 microns, where Jupiter’s spectrum is governed by temperatures, cloud opacity, and gaseous species like deuterated methane and phosphine. The map was constructed from spectral scans over two nights (March 12th-13th 2017), and represents the highest spatial resolution ever achieved by the TEXES instrument.  Every pixel in this map represents a spectrum of Jupiter.  Red colours use a wavelength that senses deep, warm temperatures at the cloud tops; blue colours sense cooler temperatures at higher altitudes near the tropopause, and green colours sense an intermediate altitude.  The equatorial zone and the Great Red Spot in the bottom right are cold and dark at all three wavelengths.  The turbulent wake to the west of the Great Red Spot is darker (cooler) and distinct from the rest of Jupiter’s South Equatorial Belt.  An outbreak of dark, cold and cloudy plumes can be seen in the southern belt near 270W.  Finally, the pattern of cold, cloudy plumes (dark) and warm, bright hotspots (white) can be seen encircling the planet near latitude 7N, on the edge of Jupiter’s Northern Equatorial Belt.

Credit:  TEXES team & L.N. Fletcher/University of Leicester, UK.

From the Gemini e-cast #93 (March 16th 2017)

TEXES, the visiting high-resolution mid-IR spectrograph, is back for another visit on Gemini North. This time the instrument is supporting a wide-ranging set of science programs, including summer-solstice observations of Saturn’s polar vortex, three programs studying Jupiter’s atmosphere, stratosphere and aurora, and (beyond the solar system) studies of the chemistry of the gaps in protoplanetary disks, organics in hot star-forming cores and the motions of gas in embedded super star clusters. At mid-IR wavelengths most of the seeing is due to image motion, which is removed by the rapid tip-tilt secondary mirror on Gemini, producing diffraction-limited images as small as 0.3 arcseconds without the use of adaptive optics.

The TEXES team has been sharing part of each night with GMOS CCD commissioning activities, reported in the previous story in this newscast, and the team is grateful for their flexibility in accommodating this TEXES visitor instrument run.

The TEXES team and Gemini staff preparing the instrument to mount on the up-looking port of Gemini North in March 2017. The beachballs are part of the instrument’s helium overflow system.

Jupiter in the 8-micron region, in a spectral scan taken by TEXES on Gemini North, March 2017. Note the cool wake of the Great Red Spot (lower right). For more details and a full color mid-IR image of the Jupiter weather layer, see the upcoming April issue of GeminiFocus. Image credit: TEXES team & L.N. Fletcher/University of Leicester, UK.

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