Fabry–Perot Imaging of Jupiter's Aurora at 2.1 μm

✍ Scribed by H. Mai; K. Jockers

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 277 KB
• Volume: 146
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2000.6402

✦ Synopsis

Jupiter was imaged in the near-infrared K band on July 22-24, 1994, i.e., shortly after the impact of Comet Shoemaker-Levy 9 (S-L9). Using the IRAC-2b near-infrared camera with Fabry-Perotinterferometer at the MPG/ ESO 2.2-m Telescope of the European Southern Observatory on La Silla in Chile, we obtained full disk images of Jupiter's H + 3 and H 2 emission at 2.093 and 2.121 µm, respectively. In two nights almost one full jovian rotation was covered. Our observations represent the first ground-based narrow-band images of Jupiter's H +

3 and H 2 emission in the K band. No impactrelated line emission is detected. In the north polar cap the aurora is clearly visible at 2.093 µm. Some emission at 2.121 µm appears close to the limb. It has different morphology and a different λ III dependence and is fainter than the H + 3 emission. Despite H 2 being a major auroral emitter in the far-UV spectral range it is not clear how its infrared emission relates to auroral phenomena. Shortly after the S-L9 impacts the intensity at 2.093 µm is slightly larger and at 2.121 µm the intensity is three times larger as compared to values provided by Drossart et al. (1989, Nature 340, 539-541). No emissions are detected in the south polar cap. This agrees with observations in the L band (Miller et al. 1997, Planet. Space Sci. 45, 1237-1250). The north polar aurora was close to normal and its vibrational temperature close to 1100 K. The Io footprint is not visible.