HR: 15:25h
AN: P53C-08    [Abstracts]
TI: Monitoring Io volcanism with AO telescopes during and after the NH flyby
AU: * Marchis, F
EM: fmarchis@berkeley.edu
AF: UC-berkeley, Department of Astronomy University of California 601 Campbell Hall, Berkeley, CA 94720-3411, United States
AU: * Marchis, F
EM: fmarchis@berkeley.edu
AF: SETI institute, 515 N. Whisman Road, Mountain View, CA 94043, United States
AU: Spencer, J R
EM: spencer@boulder.swri.edu
AF: Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, United States
AU: Lopes, R M
EM: Rosaly.M.Lopes@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA 91109, United States
AU: Davies, A G
EM: Ashley.Davies@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA 91109, United States
AU: Dumas, C
EM: cdumas@eso.org
AF: European Southern Observatory, Casilla 19001, Santiago, 19, Chile
AB: To support the New Horizons (NH) Jupiter encounter we monitored Io's volcanic activity using high angular resolution images in the near infrared (1-5 microns) provided by adaptive optics (AO) systems available on 8-10m class telescopes. We initiated the campaign on Feb. 25 2007 with data obtained with the VLT-Yepun telescope (ESO, Paranal, Chile), just before NH closest approach. We continued monitoring with the Gemini North telescope (Hawaii, USA). The last observation was taken on May 28 2007. Numerous active volcanoes are visible in the data but the Tvashtar eruption is by far the most energetic. Extremely high angular resolution data from NH revealed fine detail of the eruption, such as the presence of an active plume [1]. This volcano has an interesting past history. It was seen as a powerful eruption from Nov. 26 1999 during the Galileo I25 [2] flyby to Feb. 19 2001 from the ground [3]. It was dormant or below our ground-based limit of detection (T<330 K assuming an area of 460 km²) between Dec 2001 and May 2004 [4,5]. The re-awakening of the volcano was reported by Laver et al. [6] in April 2006 based on Keck Adaptive Optics (AO) observations. Our last Gemini AO observation taken on May 26 shows that Tvashtar was still very active. Based on the previous behavior of this volcano [7] it is very likely that the activity reported in 2007 is a continuation of the Tvashtar-2006 eruption.
Other hot spots, such as Loki Patera, Pele, and a new hot spot located north of Loki Patera, were seen in our data. We will describe the global picture of Io's volcanic activity derived from our observations, comparing it with previous observations from the Galileo spacecraft and using ground-based AO.
1. Spencer et al., AGU, this session, 2007
2. McEwen et al., Science, 288, 1193-1198, 2000
3. Marchis et al. Icarus, 160, 124-131, 2002
4. Marchis et al., Icarus, 176, 1, 2005
5. Marchis et al., AGU Fall meeting, V33C-1483, 2004
6. Laver et al., Icarus, in press, 2006
7. Milazzo et al., 2005, Icarus, 179, 235–51

DE: 1895 Instruments and techniques: monitoring
DE: 6219 Io
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting