New Horizons at Io Options

[volcanopele]

Since the New Horizons Jupiter Encounter thread is already getting pretty long, I decided to create a thread dedicated to New Horizons' observations of the most interesting object in the solar system: Io. Info on upcoming observations comes from the jupiter_timeline_static.xls document john_s posted, and the preview images are from Celestia (note that each image is scaled so that the pixel scale is ~correct, and represents a smaller FOV than LORRI)

Today, February 24, New Horizons conducts three observations of Io with the LORRI camera as well some observations of Io's atmosphere with ALICE. These observations have the lowest phase angle for Io of the entire encounter. Phase angle continues to increase as NH approaches Jupiter and Io.


The first observation, ISunMon1, shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=340.2 W) from a distance of 7,856,307 km. The resolution with LORRI would be 38.8 km/pixel. Pele is on the limb at lower right and Masubi is on the limb at lower left. Ra Patera is near center.


The second observation, ISunMon2, also shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=15.1 W) from a distance of 7,575,510 km. The resolution with LORRI would be 37.5 km/pixel. The Tvashtar plume might be poking above the limb at upper left.


The third observation, ISunMon3, shows Io's leading hemisphere (Clat=6.0 S, Clon=84.7 W) from a distance of 6,627,459 km. The resolution with LORRI would be 32.8 km/pixel. The Zamama plume might be visible just above center on the left limb.

It only gets better from here. Not sure how NH downlink works, but there is a DSN window right after the last Io observation, hopefully at least one frame from each observation will be returned. Maybe they can do the Huffman window right around where Io is... Tomorrow contains four more observations of Io, highlighting Pele and an eclipse.

[volcanopele]

Today, February 25, New Horizons conducts three monitoring observations of Io with the LORRI camera focusing on the trailing hemisphere, as well some observations of Io's atmosphere with ALICE and an observation of Io while it is in eclipse with the LORRI, ALICE, and RALPH instruments. As noted in the post above, these observations won't be returned until next month.

Please keep in mind that these are simulations of the LORRI frames from Celestia, not the LORRI frames themselves...


The first observation, ISunMon5, shows Io's trailing hemisphere (Clat=3.0 S, Clon=225.4 W) from a distance of 5,276,976 km. The resolution with LORRI would be 26.1 km/pixel. Pele is visible at lower left and Prometheus is at center right. If Loki's plume(s) are active, then it *might* be visible at upper left.


The second observation, ISunMon6, shows Io's trailing hemisphere (Clat=3.0 S, Clon=253.1 W) from a distance of 5,217,587 km. The resolution with LORRI would be 25.8 km/pixel. Pele is now just below center and Loki has rotated into view at upper left. Prometheus' plume might be visible at center right, though as noted in the above posts, this might not be the best viewing geometry for observing Io's plumes given LORRI's wavelength range.


The third observation, ISunMon7, shows Io's trailing hemisphere (Clat=3.0 S, Clon=308.1 W) from a distance of 5,184,145 km. The resolution with LORRI would be 25.6 km/pixel. Pele is now visible at lower right. Loki is now visible near center. Not sure where Loki is in its geological clock, but the SNR of LORRI might be enough to allow one to see where the overturn front is in Loki Patera.

The final observation is Ieclipse1, an observation of Io in eclipse. RALPH will be active during the eclipse, allowing for an observation of Io's current volcanic activity. Loki should be easily visible in the LEISA images, depending again on where it is in its geological clock...