| Name | DDT_pharto01_6 |
| Title | First ever detection of Callisto.s atmosphere and constraining the trailing side atmosphere of Ganymede |
| URL | http://archives.esac.esa.int/hsa/whsa-tap-server/data?retrieval_type=OBSERVATION&observation_id=1342265961&instrument_name=HIFI&product_level=LEVEL0&compress=true |
| DOI | https://doi.org/10.5270/esa-9axm1s4 |
| Author | hartogh, p. |
| Description | On 16 September 2012 we got the first ever detection of the Ganymede water atmosphere with HIFI as part of the HssO GTKP, observing the leading side of this Galilean moon. The production processes of Ganymedes atmosphere are debated. Possible candidates are sputtering/interaction with Jupiters magnetic field and sublimation. Since Jupiters magnetic field rotates faster than Ganymedes orbital period, sputtering as the main production process should lead to a larger production rate at the trailing side of Ganymede. A more massive water atmosphere at the trailing side would therefore indicate that sputtering is the main atmosphere production process. If sublimation is the main production process the leading side atmosphere should be heavier, because the amount of ice exposed to solar irradiance is larger. We therefore propose an observation of Ganymedes trailing side with 2 hours in Frequency Switch (FS) mode. We will also search for H2O gas in Callisto, targeting the first ever detection of Callisto.s water atmosphere. We note that Callisto.s surface has a lower albedo than either side of Ganymede, and a higher surface temperature. At the same time, the surface area of ice exposed to the Sun may be smaller than at Ganymede. Therefore, beyond the pure detection aspect, the measurement of Callisto.s atmosphere will provide an additional element for the understanding the sources of the Galilean satellite tenuous atmospheres. Again, only 2 hours of HIFI time in FS mode are needed for the Callisto observation. There are three observation windows for Ganymede with the first starting on February 10 and one observation window for Callisto starting on 12 February 2013. |
| Publication | |
| Instrument | HIFI_HifiPoint_fs |
| Temporal Coverage | 2013-03-05T11:08:43Z/2013-03-10T13:04:30Z |
| Version | SPG v14.1.0 |
| Mission Description | Herschel was launched on 14 May 2009! It is the fourth cornerstone mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities. |
| Creator Contact | https://support.cosmos.esa.int/h®erschel/ |
| Date Published | 2013-09-10T10:44:18Z |
| Keywords | Herschel, HSC, submillimetre, far-infrared, HIFI, PACS, SPIRE |
| Publisher And Registrant | European Space Agency |
| Credit Guidelines | European Space Agency, hartogh et al., 2013, 'First ever detection of Callisto.s atmosphere and constraining the trailing side atmosphere of Ganymede', SPG v14.1.0, European Space Agency, https://doi.org/10.5270/esa-9axm1s4 |