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]

Now back to everyone's favorite moon...

Today, February 28, New Horizons makes its closest approach to Jupiter. There are six observations planned during this closest approach period, including 4 high resolution observation, 2 multi-spectral observations with LORRI, MVIC, and LEISA, and another stellar occultation.

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


The first observation, Ihires4, shows Io's sub-Jovian hemisphere Clat=6.1 S, Clon=21.6 W) from a distance of 2,692,601 km. The resolution with LORRI would be 13.3 km/pixel. The phase angle has increase substantially since the last Io observation, Ieclipse3, yesterday. Now only a little more than half of Io is illuminated by the sun from this vantage point. However, the portion not illuminated by the sun is illuminated by Jupiter, allowing for Jupiter-shine observations.


The second observation, Ihiresir3, shows Io's sub-Jovian hemisphere (Clat=6.0 S, Clon=25.8 W) from a distance of 2,675,561 km. The resolution with LORRI would be 13.2 km/pixel. Taken only a few minutes after the Ihires4 observation, not much has changed, but now RALPH will be getting in on the action, making multi-spectral observations.


The third observation, Iocc2, is the second of two Io stellar occultations. No LORRI frames are planned, just ALICE observations.


The fourth observation, Ihires5, shows Io's leading hemisphere (Clat=5.7 S, Clon=63.9 W) from a distance of 2,489,864 km. The resolution with LORRI would be 12.3 km/pixel. The phase angle continues to increase, now at 102.3 degrees. The Prometheus and Tvashtar plumes should now be easily visible along the limb. The new Shango Patera flow should also be visible. This observation is already on the ground. Hopefully, we will see it soon.



The fifth observation, Ishine1, show Io's leading hemisphere (Clat=5.5 S, Clon=76.6 W) from a distance of 2,426,086 km. The resolution with LORRI would be 12.0 km/pixel. The phase angle will be 106.6 degrees. This multi-spectral observation is designed to examine the sub-Jovian hemisphere in Jupiter-shine with MVIC and LEISA. Is Shango still active?


The final observation of the day, Ihires6, shows Io's leading hemisphere (Clat=5.4 S, Clon=90.0 W) from a distance of 2,364,560 km. The resolution with LORRI would be 11.7 km/pixel. Prometheus is now rotating into view.