30 Years of Planetary Astronomy with H3+

JUNO JIRAM infrared image of Jupiter’s southern aurora - Image credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM
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End Date

A Royal Astronomical Society Specialist Discussion Meeting organised by *Steve Miller (UCL); Nick Achilleos (UCL)


JUNO JIRAM infrared image of Jupiter’s southern aurora - Image credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

2018 marks the 30th anniversary of the serendipitous discovery of the H3+ molecular ion in Jupiter’s northern aurora. The discovery itself was the result of an impromptu collaboration between astronomical observers, telescope instrument builders, laboratory spectroscopists and molecular physicists. H3+ emission has subsequently been detected from Saturn and Uranus, of the Solar System’s giant planets, but not Neptune. As an energetic and reactive molecular ion, H3+ is now used as a tracer for energy inputs, via particle precipitation, into giant planets’ atmospheres from their enormous magnetospheres: variations in emission levels are used to monitor both shorter-term magnetospheric dynamics, caused by changes in internal (plasma density) and external (solar wind dynamic pressure) factors, and longer-term changes that may result from the solar cycle and seasonal changes in solar irradiation. The final results from Cassini – particularly the VIMS instrument – and new measurements from JUNO mean that there is a wealth of data to add to and complement that being generated from ground-based observations. All-in-all, there is a wealth of material to review and huge current interest in just how this simple molecular ion behaves and what it tells us about planets in our Solar System and beyond. 

Confirmed speakers:

Nick Achilleos, UCL
Sarah Badman, University of Lancaster
Marina Galand, ICSTM
Jean-Pierre Maillard, Observatoire de Paris
Henrik Melin, University of Leicester
Steve Miller, UCL
Renee Prange, LESIA, Observatoire de Paris, Meudon
Licia Ray, University of Lancaster
Tom Stallard, University of Leicester

30 years of planetary astronomy with H3+

Convenors: Steve Miller, Nick Achilleos, University College London


10:30 am start (Chairs: Nick Achilleos / Steve Miller)

  1. Jean-Pierre Maillard      The Discovery of H3+ in the auroral regions of Jupiter
  2. Steve Miller                       Some chemical and physical properties of H3+
  3. Renee Prange                    Comparing UV and H3+ observations
  4. Marina Galand                  Models of electron precipitation
  5. Nick Achilleos                  Coupled magnetosphere-atmosphere models
  6. Sarah Badman                  Cassini/VIMS at Saturn

12:20 – 12:40 short discussion

12:40 Lunch and posters

13:40-15:00 (Chair: Licia Ray)

  1. Tom Stallard                    Ground-based IR observations of Jupiter
  2. Alessandro Mura             H3+ auroral emission results from JIRAM and vertical profiles derived from satellite footprints
  3. Alessandra Migliorini       Limb measurements of H3+ at auroral and mid-low latitudes with JIRAM
  4. Henrik Melin                    Long-term ground-based observations of Uranus

15:00 – 15:30 Reflections and discussion led by Licia Ray

15:30 finish

There are also a few slots available for contributed talks and posters are welcome.


Admission to Specialist Discussion Meetings is free for RAS Fellows, £15 for non-fellows (£5 for students), cash or cheque only, collected at the registration desk.  Admission to the subsequent Open (Monthly A&G) Meeting of the Royal Astronomical Society is open to all, at no charge

Venue Address

The Royal Astronomical Society,Burlington House


51.5085763, -0.13960799999995