A Search for Water Vapor Plumes on Europa using SOFIA. (arXiv:1901.00086v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sparks_W/0/1/0/all/0/1">William Sparks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Richter_M/0/1/0/all/0/1">M. Richter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+deWitt_C/0/1/0/all/0/1">C. deWitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montiel_E/0/1/0/all/0/1">E. Montiel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Russo_N/0/1/0/all/0/1">N. Dello Russo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grunsfeld_J/0/1/0/all/0/1">J. Grunsfeld</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McGrath_M/0/1/0/all/0/1">M. A. McGrath</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weaver_H/0/1/0/all/0/1">H. Weaver</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hand_K/0/1/0/all/0/1">K.P. Hand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bergeron_E/0/1/0/all/0/1">E. Bergeron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reach_W/0/1/0/all/0/1">W. Reach</a>
We present mid-infrared SOFIA/EXES spectroscopy of Europa, seeking direct
evidence of the presence of water vapor arising from plumes venting from the
surface of Europa. We place quantitatively useful upper limits on the strength
of water vibrational-rotational emission lines. Conversion to water mass limits
is dependent on the rotational temperature of the vapor. For low rotational
temperature, the limits lie below the inferred water mass from previous HST
plume observations. For higher temperatures, the limits are comparable. We also
present coordinated HST transit observations obtained close in time to the
SOFIA observations. There is evidence for a feature close to the location of
the previously seen feature north of the crater Pwyll in one of the HST images,
although it was not observable by EXES given its location. We conclude that if
a water plume had been active at the time of the SOFIA observation, with the
strength implied by previous HST observations, then under the right Earth
atmospheric and geometric conditions, the plume could have been detected by
EXES, however no IR water vibrational-rotational emission was detected.
We present mid-infrared SOFIA/EXES spectroscopy of Europa, seeking direct
evidence of the presence of water vapor arising from plumes venting from the
surface of Europa. We place quantitatively useful upper limits on the strength
of water vibrational-rotational emission lines. Conversion to water mass limits
is dependent on the rotational temperature of the vapor. For low rotational
temperature, the limits lie below the inferred water mass from previous HST
plume observations. For higher temperatures, the limits are comparable. We also
present coordinated HST transit observations obtained close in time to the
SOFIA observations. There is evidence for a feature close to the location of
the previously seen feature north of the crater Pwyll in one of the HST images,
although it was not observable by EXES given its location. We conclude that if
a water plume had been active at the time of the SOFIA observation, with the
strength implied by previous HST observations, then under the right Earth
atmospheric and geometric conditions, the plume could have been detected by
EXES, however no IR water vibrational-rotational emission was detected.
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