| |
 |
| Paper: |
The Molecular Ion H3+ in Emission in Planetary Atmospheres |
| Volume: |
450, Molecules in the Atmospheres of Extrasolar Planets |
| Page: |
19 |
| Authors: |
Maillard, J.; Miller, S. |
| Abstract: |
The molecular ion H3+ was detected by spectroscopy twenty years ago,
for the first time outside of the laboratory, in the upper atmosphere of
the polar zones of Jupiter. This detection made possible temperature,
abundance measurements, imaging of the ionic emission, and triggered its
search in the atmosphere of the other giant planets, leading to a
positive detection in Saturn and Uranus. These measurements, mainly in
the ν2 band around 3.7 μm and its overtone 2ν2 at
2.1 μm, revealed a wealth of information on the planetary
magnetospheres and the auroral phenomenon. On the hot Jupiters, H3+,
likely excited through EUV radiation, could be an important target to
prove the existence of a gaseous planet and to monitor the escape
processes of the atmosphere. The attempts of detection in exoplanets
have been so far unsuccessful with the current limits of detection.
From the experience gained on the role played by this ion in the energy
balance of the giant planets of the Solar System, can be inferred its
role of thermostat in the upper atmosphere and the ionosphere of giant
extrasolar planets as main cooling agent contributing to their
stability. However, the distance to the star is an important parameter
for H3+ to be able to form. Occultation spectroscopy with more
transiting planets known should be the most promising method for this
search. |
|
|
|
|
|
