Stellar Occultation by Comet 67P/Churyumov–Gerasimenko Observed with Rosetta's Alice Far-ultraviolet Spectrograph
AuthorKeeney, Brian A.
Stern, S. Alan
Feldman, Paul D.
A’Hearn, Michael F.
Feaga, Lori M.
Knight, Matthew M.
Medina, Richard A.
Parker, Joel Wm.
Pineau, Jon P.
Schindhelm, Rebecca N.
Steffl, Andrew J.
Vervack, Ronald J.
Weaver, Harold A.
AffiliationUniv Arizona, Lunar & Planetary Lab
MetadataShow full item record
PublisherAmerican Astronomical Society
CitationKeeney, B. A., Stern, S. A., Feldman, P. D., A’Hearn, M. F., Bertaux, J., Feaga, L. M., . . . Weaver, H. A. (2019). Stellar Occultation by Comet 67P/Churyumov–Gerasimenko Observed with Rosettas Alice Far-ultraviolet Spectrograph. The Astronomical Journal, 157(5), 173. doi:10.3847/1538-3881/ab1097
RightsCopyright © 2019. The American Astronomical Society. All rights reserved.
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AbstractFollowing our previous detection of ubiquitous H2O and O-2 absorption against the far-ultraviolet continuum of stars located near the nucleus of Comet 67P/Churyumov-Gerasimenko, we present a serendipitously observed stellar occultation that occurred on 2015 September 13, approximately one month after the comet's perihelion passage. The occultation appears in two consecutive 10-minute spectral images obtained by Alice, Rosetta's ultraviolet (700-2100 angstrom) spectrograph, both of which show H2O absorption with column density >10(17.5) cm(-2) and significant O-2 absorption (O-2/H2O approximate to 5%-10%). Because the projected distance from the star to the nucleus changes between exposures, our ability to study the H2O column density profile near the nucleus (impact parameters <1 km) is unmatched by our previous observations. We find that the H2O and O-2 column densities decrease with increasing impact parameter, in accordance with expectations, but the O(2 )column decreases similar to 3 times more quickly than H2O. When combined with previously published results from stellar appulses, we conclude that the O-2 and H2O column densities are highly correlated, and O-2/H(2)Odecreases with the increasing H2O column.
VersionFinal published version
SponsorsNASA via Jet Propulsion Laboratory