Search for volatiles on icy satellites. I. Europa

Robert H. Brown, Dale P. Cruikshank, Alan T. Tokunaga, Robert G. Smith, Roger N. Clark

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

New reflectance spectra have been obtained for both the leading and trailing sides of Europa, using the Cooled Grating Array Spectrometer (CGAS) of the NASA Infrared Telescope Facility (IRTF). The spectra are of higher precision than any yet obtained. Spectra of Europa's trailing side (central meridian longitude ≈300°) obtained in 1985 show two weak absorptions near 2.2 and 2.3 μm. Both of these features as well as others are seen in spectra obtained by R. N. Clark, R. B. Singer, P. D. Owensby, and F.P. Fanale (1980a, Bull. Amer. Astron. Soc. 12, 713-714) at similar central meridian longitude. Data obtained with an improved detector array in 1986, however, do not show the absorptions seen in the 1980 and 1985 spectra. It is not clear why the newest data do not show the apparent absorptions seen in previous years, but the suggestion is that either the 1980 and 1985 data are spurious or that the material responsible for the weak absorptions is no longer detectable. Analysis of the 1980 and 1985 data did not reveal any obvious source of systematic error capable of introducing spurious features, but we are skeptical of any explanation that cites transient deposition, movement, and/or destruction of material on Europa's trailing side to account for the nondetection of the features in the 1986 data. If the weak absorptions seen in the 1980 and 1985 data are real, they can be interpreted as indicating the transient spectroscopic presence of a molecular component on Europa's trailing side different from the water ice that is known to be the dominant surface constituent. Further monitoring is required to determine if the apparent absorptions are real.

Original languageEnglish (US)
Pages (from-to)262-271
Number of pages10
JournalIcarus
Volume74
Issue number2
DOIs
StatePublished - 1988
Externally publishedYes

Fingerprint

icy satellites
Europa
longitude
infrared telescopes
systematic errors
destruction
suggestion
reflectance
ice
spectrometer
gratings
spectrometers
detectors
monitoring
water

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Brown, R. H., Cruikshank, D. P., Tokunaga, A. T., Smith, R. G., & Clark, R. N. (1988). Search for volatiles on icy satellites. I. Europa. Icarus, 74(2), 262-271. https://doi.org/10.1016/0019-1035(88)90041-3

Search for volatiles on icy satellites. I. Europa. / Brown, Robert H.; Cruikshank, Dale P.; Tokunaga, Alan T.; Smith, Robert G.; Clark, Roger N.

In: Icarus, Vol. 74, No. 2, 1988, p. 262-271.

Research output: Contribution to journalArticle

Brown, RH, Cruikshank, DP, Tokunaga, AT, Smith, RG & Clark, RN 1988, 'Search for volatiles on icy satellites. I. Europa', Icarus, vol. 74, no. 2, pp. 262-271. https://doi.org/10.1016/0019-1035(88)90041-3
Brown RH, Cruikshank DP, Tokunaga AT, Smith RG, Clark RN. Search for volatiles on icy satellites. I. Europa. Icarus. 1988;74(2):262-271. https://doi.org/10.1016/0019-1035(88)90041-3
Brown, Robert H. ; Cruikshank, Dale P. ; Tokunaga, Alan T. ; Smith, Robert G. ; Clark, Roger N. / Search for volatiles on icy satellites. I. Europa. In: Icarus. 1988 ; Vol. 74, No. 2. pp. 262-271.
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