Jupiter Today | 17 August 2015 | Io Transits

Hello!

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 starts the day in quad 1 moving east very close to its eastern elongation.  Europa also begins the day in quad 1 moving east.  Ganymede is in quad 4 moving east all day.  Callisto starts the day in quad 3 heading west.

By 6h UTC, Io is past its eastern elongation and is now firmly in quad 2 moving west.  Callisto is very near its western elongation and will be moving into quad 4 heading east.

At 12h UTC, Io is beginning its transit of Jupiter.  Europa is near its eastern elongation and will be moving into quad 2 moving west.

By 18h UTC, Io is firmly in quad 3 moving west, Europa is firmly in quad 2 heading west.  Callisto has now settled into quad 4 moving east which is will do for the next few days.

At 0h UTC tomorrow, Io is at western elongation and moving into quad 4 headed west.  Europa is in quad 2 moving west.  Ganymede and Callisto continue in quad 4 moving east.

At 12:31 UTC, Io goes through an apojove at a distance of 423,488.233 km.

At 0h UTC, the position of Jupiter on Earth's celestial sphere is RA 10h 13m 21.6s, DEC +11d 55m 59.4s.  The phase angle is 1.396 degrees, which is 0.139 degrees less than yesterday.  The angle between Jupiter and the Sun as seen from Earth is 7.447 degrees, which is 0.74 degrees less than yesterday.  Jupiter continues to move radially away from the sun in its orbit at a distance of 805,689,209 km, which is 36,818 km greater than yesterday.  The radial velocity of Jupiter relative to the Sun is 1,534.083 km/h, which is 5.75 km/h slower than yesterday.  The distance between Jupiter and Earth is 955,653,128 km, which is 324,898 km further apart than yesterday.  Jupiter and Earth are moving apart at a velocity of 13,537.417 km/h, which is 1,287.833 km/h slower than yesterday.  The radial velocity is half of what it was just ten days ago on 7 August 2015, when it was 26,213.333 km/h.

From 11:54 to 14:13 UTC, Io transits Jupiter.  From 12:04 to 14:22 UTC, the shadow of Io transits Jupiter.

There are no satellite mutual events today.

Orbital Ribbons for 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.



Jupiter is now firmly in the SOHO LASCO C3 field of view.  Unfortunately, it looks like it's saturating the CCD, so no reliable photometry is possible:

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Please send me your feedback, comments, and questions to jupitertoday AT gmail DOT com or the comments section of this blog.

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.