ALMA Thermal Observations of a Proposed Plume Source Region on Europa
We present a daytime thermal image of Europa taken with the Atacama Large Millimeter Array. The imaged region includes the area northwest of Pwyll Crater, which is associated with a nighttime thermal excess seen by the Galileo Photopolarimeter Radiometer and with two potential plume detections. We develop a global thermal model of Europa and simulate both the daytime and nighttime thermal emission to determine if the nighttime thermal anomaly is caused by excess endogenic heat flow, as might be expected from a plume source region. We find that the nighttime and daytime brightness temperatures near Pwyll Crater cannot be matched by including excess heat flow at that location. Rather, we can successfully model both measurements by increasing the local thermal inertia of the surface.
Additional Information© 2017 American Astronomical Society. Received 2017 July 12; revised 2017 August 11; accepted 2017 August 17; published 2017 September 15. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.01302.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research was supported by grant 1313461 from the National Science Foundation. The authors thank John R. Spencer for kindly providing the Galileo PPR data used within this paper.
Published - Trumbo_2017_AJ_154_148.pdf
Submitted - 1708.07922.pdf