JUPITER TODAY is a daily blog about the dynamic Jupiter system for the purpose of monitoring activity.
We start with the overall view of activity with the Jupiter system, showing the orbits of the four Galilean moons:
This is a view of the Jupiter system looking down on it. Following the blue line to the left is the line of sight to Earth, while following the gray line to the left is the line of sight to the Sun. The orbits of the four Galilean moons are shown. The large dots indicate the position of each moon at 0h, 6h, 12h, 18h, and 24h (0h the next day) UTC for this date. From this point of view, the moons revolve around Jupiter in a counter-clockwise motion. For more information about this graphic, see the post from 30 July 2015.
At 0h UTC, Io begins the day in quad 2 moving west and will be transiting Jupiter soon. Europa is in quad 3 moving west very near its western elongation. Io will be catching up to and passing Europa today. Ganymede begins the day in quad 1 moving east. Callisto spends all day moving east away from Jupiter in quad 1.
By 0h UTC tomorrow, Io and Europa are both moving behind Jupiter and will be doing into quad 1 heading east. Ganymede is finally at its eastern elongation. Callisto continues in quad 1 slowing moving east.
Io goes through its apojove (the furthest it will be in this orbit) at 04:25 UTC at a distance of 432,484.8 km.
At 0h UTC, the position of Jupiter on Earth's celestial sphere is RA 10h 03m 27.5s, DEC 12d 50m 03.9s. The phase angle is 3.042 degrees, which is 0.135 degrees less than yesterday. The angular separation between Jupiter and the Sun as seen from Earth is 16.351 degrees, which is 0.744 degrees less than yesterday. The distance between Jupiter and the Sun today is 805,241,933 km, which is 37,645 km. Jupiter is radially moving away from the Sun in it's ~12 year orbit. This gives a radial velocity between Jupiter and the Sun of 1,568.542 km/h, which is 1.042 km/h faster than yesterday. The wobbling continues. The distance between Jupiter and the Earth is 949,379,983 km. This is 688,166 km further away than yesterday. This gives a radial velocity of 28,673.583 km/h, which is 1,219.334 km/h slower than yesterday.
Relative to Jupiter, the Earth is moving away from Jupiter at a slower and slower velocity. This will continue until Superior Conjunction, when our relative motion will stop and reverse and we'll start moving toward Jupiter once again.
From 02:21 to 04:40 UTC, Io transits Jupiter. This is a 139 minute event. The shadow of Io transits Jupiter from 02:43 to 05:01 UTC. At 22:27 UTC, Europa moves behind Jupiter. At 23:38 UTC, Io moves behind Jupiter.
From 14:29 to 14:41 UTC, Io occults Europa, This is a 11.5 minute event with an impact parameter of 0.263 arc seconds. A pretty nice occultation. From 15:15 to 15:29 UTC, Io eclipses Europa. This 14.2 minute event has an impact parameter of 0.323 arc seconds. A nice eclipse. Wish I was there to actually see it instead of relying on mathematics and computers to simulate the experience. Ah well, I'm there doing it anyhow -- I'm just not able to be aware of it.
Orbital Ribbons today:
Jupiter is so near Superior Conjunction (taking place at 22:00 UTC on 26 August 2015) that photography and other data collection isn't practical. We'll have to wait about a months after SC to start viewing the Jupiter system again.
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With my gratitude, the data used to create the orbit plots and ribbons was supplied by the JPL Horizons website. The graphics showing the location of the four moons as seen from Earth are via 'Jupiter Viewer 2.8'. Jupiter-Satellite and Satellite mutual events data is supplied from IMCEE.
Until tomorrow, I bid you Peace.
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