John R. Spencer Biobibliography Articles Abramov, O. and J.R. Spencer 2008. South polar anomaly on Enceladus: Observations and modeling. Icarus, submitted. Reuter, D. C, S.A. Stern, J. Scherrer, D.E. Jennings, J.W. Baer, J. Hanley, L. Hardaway, A. Lunsford, S. McMuldroch, J. Moore, C. Olkin, R. Parizek, H. Reitsma, D. Sabatke, J. Spencer, J. Stone, H. Throop, J. Van Cleve, G.E. Weigle and L.A. Young 2008. Ralph: A Visible/Infrared Imager for the New Horizons Pluto/Kuiper Belt Mission. Space Science Reviews 84 (18 pages). Cheng, A.F., A. Simon-Miller, H. Weaver, K. Baines, G.S. Orton, P. Yanamandra-Fisher, O. Mousis, E. Pantin, L. Vanzi, L.N. Fletcher, J.R. Spencer, S.A. Stern, J.T. Clarke, M.J. Mutchler, K.S. Noll, 2008. Changing Characteristics of Jupiter's Little Red SPOT. Astron. J. 135, 2446-2452. Abramov, O., and J.R. Spencer 2008. Numerical modeling of endogenic thermal anomalies on Europa. Icarus 195, 378-385. Grundy, W.M., K.S. Noll, J. Virtanen, K. Muinonen, S.D. Kern, D.C. Stephens, J.A. Stansberry, H.F. Levison, J.R. Spencer 2008. (42355) Typhon-Echidna: Scheduling Observations for Binary Orbit Determination. Icarus, in press (17 pages). Grundy, W.M., J.A. Stansberry, K.S. Noll, D.C. Stephens, D.E. Trilling, S.D. Kern, J.R. Spencer, D.P. Cruikshank, H.F. Levison 2007. The orbit, mass, size, albedo, and density of (65489) Ceto/Phorcys: A tidally-evolved binary Centaur. Icarus 191, 286-297. Stansberry, J., W. Grundy, M. Brown, D. Cruikshank, J. Spencer, D. Trilling, J.-L. Margot 2007. In "The Solar System Beyond Neptune" (M. Barucci et al., Eds), U. Arizona Press, Tucson (19 pages) Spencer, J.R., S.A. Stern, A.F. Cheng, H.A. Weaver, D.C. Reuter, K. Retherford, A. Lunsford, J.M. Moore, O. Abramov, R.M.C. Lopes, J.E. Perry, L. Kamp, M. Showalter, K.L. Jessup, F. Marchis, P.M. Schenk, C. Dumas 2007. Io Volcanism Seen by New Horizons: A Major Eruption of the Tvashtar Volcano. 2007. Science 318, 240-243. Retherford, K.D., J.R. Spencer, S.A. Stern, J. Saur, D.F. Strobel, A.J. Steffl, G.R. Gladstone, H.A. Weaver, A.F. Cheng, J.W. Parker, D.C. Slater, M.H. Versteeg, M.W. Davis, F. Bagenal, H.B. Throop, R.M.C. Lopes, D.C. Reuter, A. Lunsford, S.J. Conard, L.A. Young, J. Moore, 2007. Io's Atmospheric Response to Eclipse: UV Aurorae Observations. Science 318, 237. Grundy, W. M., B.J. Buratti, A.F. Cheng, J.P. Emery, A. Lunsford, W.B. McKinnon, J.M. Moore, S.F. Newman, C. Olkin, D.C. Reuter, P.M. Schenk, J.R. Spencer, S.A. Stern, H.B. Throop, H.A. Weaver 2007. New Horizons Mapping of Europa and Ganymede. Science 318, 234. Showalter, M.R., A.F. Cheng, H.A. Weaver, S.A. Stern, J.R. Spencer, H.B. Throop, E.M. Birath, D. Rose, J. Moore, 2007. Clump Detections and Limits on Moons in Jupiter's Ring System. Science 318, 232. Baines, K.H., A.A. Simon-Miller, G.S. Orton, H.A. Weaver, A. Lunsford, T.W. Momary, J.R. Spencer, A.F. Cheng, D.C. Reuter, D.E. Jennings, G.R. Gladstone, J. Moore, S.A. Stern, L.A. Young, H. Throop, P. Yanamandra-Fisher, B.M. Fisher, J. Hora, M.E. Ressler, 2007. Polar Lightning and Decadal-Scale Cloud Variability on Jupiter. Science 318, 226. Reuter, D.C., A.A. Simon-Miller, A. Lunsford, K.H. Baines, A.F. Cheng, D.E. Jennings, C.B. Olkin, J.R. Spencer, S.A. Stern, H.A. Weaver, L.A. Young 2007. Jupiter Cloud Composition, Stratification, Convection, and Wave Motion: A View from New Horizons. Science 318, 223. McNutt, R.L., D.K. Haggerty, M.E. Hill, S.M. Krimigis, S. Livi, G.C. Ho, R.S. Gurnee, B.H. Mauk, D. Mitchell, E.C. Roelof, D.J. McComas, F. Bagenal, H.A. Elliott, L.E. Brown, M. Kusterer, J. Vandegriff, S.A. Stern, H.A. Weaver, J.R. Spencer, J.M. Moore 2007. Energetic Particles in the Jovian Magnetotail. Science 318, 220. Jessup, K.L, J.R. Spencer, R. Yelle, R. 2007 Sulfur volcanism on Io. Icarus 192, 24-40. Nimmo, F., J. R. Spencer, R. T. Pappalardo, and M. E. Mullen 2007. Shear heating as the origin of the plumes and heat flux on Enceladus. Nature 447, 289-291. Spencer, J. R., and D. H. Grinspoon 2007. News and Views: Inside Enceladus. Nature 445 376-377. Kieffer, S.W., C. M. Bethke, J. R. Spencer, S. Marshak, A. Navrotsky 2006. A clathrate reservoir hypothesis for Enceladus' south polar plume. Science 314, 1764-1766.. Lopes, R. M. C. and J. R. Spencer (eds.) 2006. Io after Galileo: A New View of Jupiters Volcanic Moon. Praxis, Chichester, U.K. Perry, J., J.R. Spencer, and C. Alexander 2006. A summary of the Galileo mission and its observations of Io. In Io After Galileo (R. Lopes and J. Spencer, eds.) Praxis, Chichester, U.K., pp. 35-60. Moore, W.B., G. Schubert, J.D. Anderson, and J.R. Spencer 2006. In Io After Galileo (R. Lopes and J. Spencer, eds.) Praxis, Chichester, U.K., pp. 89-108. Marchis, F., J.R. Spencer, and R.M.C. Lopes 2006. Outstanding questions and future explorations. In Io After Galileo (R. Lopes and J. Spencer, eds.) Praxis, Chichester, U.K., pp. 287-306. Grundy, W. M.; Young, L. A.; Spencer, J. R.; Johnson, R. E.; Young, E. F.; Buie, M. W. 2006. Distributions of H2O and CO2 ices on Ariel, Umbriel, Titania, and Oberon from IRTF/SpeX observations. Icarus 184, 543-555. Steffl, A.J., M.J. Mutchler, H.A. Weaver, S.A. Stern, D.D. Durda, D. Terrell, W.J. Merline, L.A. Young, E.F. Young, M.W. Buie, and J.R. Spencer 2006. New constraints on additional satellites of the Pluto system. Astron. J., 132, 614-619. Stern, S.A., H.A. Weaver, H.A., A.J. Steffl, M.J. Mutchler, W.J. Merline, M.W. Buie, E.F. Young, L.A. Young, and J.R. Spencer, 2006. A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper Belt. Nature 439, 946-948. Weaver, H.A., S.A. Stern, M.J. Mutchler, A.J. Steffl, M.W. Buie, W.J. Merline, J.R. Spencer, E.F. Young, and L.A. Young 2006. Discovery of two new satellites of Pluto. Nature 439, 943-945. Spencer J.R., J. C. Pearl, M. Segura, F. M. Flasar, A. Mamoutkine, P. Romani, B. J. Buratti, A. R. Hendrix, L. J. Spilker, and R. M. C. Lopes 2006. Cassini encounters Enceladus: Background, and the discovery of a south polar hot spot. Science 311,1401-1405. Spencer, J.R., W. M. Grundy, C. Dumas, R. W. Carlson, T. B. McCord, G. B. Hansen, and R. J. Terrile 2006. The nature of Europa's dark non-ice surface material: Spatially-resolved high spectral resolution spectroscopy from the Keck telescope. Icarus 182, 202-210. Spencer, J.R., E. Lellouch, M. J. Richter, M. A. Lopez-Valverde, K. L. Jessup, T. K. Greathouse, and J-M. Flaud 2005. Mid-infrared detection of large longitudinal asymmetries in Io's SO2 atmosphere. Icarus, 176, 283-304. Grundy, W.M., M.W. Buie, and J.R. Spencer 2005. Near-infrared spectrum of low-inclination classical Kuiper Belt Object (79360) 1997 CS29. Astron. J. 130, 1299-1301. Flasar, F.M. and 45 co-authors including J.R. Spencer 2005. Titan's atmospheric temperatures, winds, and composition. Science 308, 975-978. Flasar, F.M. and 46 co-authors including J.R. Spencer 2005. Temperatures, winds, and composition in the Saturnian system. Science 307, 1247-1251. \ref Mendillo, M., J. Wilson, J. Spencer, and J. Stansberry 2004. Io's volcanic control of Jupiter's extended neutral clouds. Icarus, 170, 430-442. \ref Flasar, F.M. and 44 co-authors including J.R. spencer 2004. Exploring the Saturn system in the thermal infrared: The composite infrared spectrometer. Space Sci. Rev. 115, 169-297. \ref Spencer, J.R., M.W. Buie, L. Young, and A. Stern 2004. Finding KBO Flyby targets for New Horizons. Proceedings of the First Decadal Review of the Edgeworth-Kuiper Belt, A. Davies Ed., ISBN 1-4020-1781-2, reprinted from Earth Moon and Planets 92. \ref Stern, A., and J. Spencer 2004. New Horizons, The first reconnaisance mission to bodies in the Kuiper Belt. Proceedings of the First Decadal Review of the Edgeworth-Kuiper Belt, A. Davies Ed., ISBN 1-4020-1781-2, reprinted from Earth Moon and Planets 92. \ref Jessup, K.L., J.R. Spencer, G.E. Ballester, R.R. Howell., F. Roesler, M. Vigil, and R. Yelle 2003. The atmospheric signature of Io's Prometheus plume and anti-Jovian hemisphere: Evidence for a sublimation atmosphere. Icarus 169, 197-215. \ref Rathbun, J. A., J. R. Spencer, L. K. Tamppari, T. Z. Martin, L. Barnard, and L. D. Travis 2003, Mapping of Io's Thermal Radiation by the Galileo Photopolarimeter-Radiometer (PPR) Instrument. Icarus 169, 127-139. \ref Geissler, P. A. McEwen, C. Phillips, L. Keszthelyi, and J. Spencer 2004. Surface changes on Io during the Galileo mission. Icarus 169, 29-64. \ref Spencer, J.R., R.W. Carlson, A.S. McEwen, T. Becker, and J. Blue 2004. Maps and spectra of Jupiter and its satellites. Chapter in Jupiter (F. Bagenal, ed.), Cambridge University Press, in press. \ref McEwen, A.S., L.P. Keszthelyi, R. Lopes, P. Schenk, and J.R. Spencer 2004. The Lithosphere and surface of Io. Chapter in Jupiter (F. Bagenal, ed.), Cambridge University Press, in press. \ref Moore, J., B. Bierhaus, C. Chapman, F. Chuang, R. Clark, R. Greely, C. Hibbits, J. Klemaszewski, P. Schenk, J. Spencer, and R. Wagner 2004. Callisto. Chapter in Jupiter (F. Bagenal, ed.), Cambridge University Press, in press. \ref Pappalardo, R., G. Collins, P. Helfenstein, T. McCord, L. Prockter, P. Schenk, and J. Spencer 2004. Ganymede. Chapter in Jupiter (F. Bagenal, ed.), Cambridge University Pres, in press. \ref Rathbun, J.A., J.R. Spencer, A.G. Davies, R.R. Howell, and L. Wilson (2002). Loki, Io: A periodic volcano. Geophys. Res. Lett. 29, Issue 10, pp. 84-1, CiteID 1443,DOI 10.1029/2002GL014747. Macintosh, B. A., Gavel, D., Gibbard, S.G., Max, C.E., Eckart, M., de Pater, I., Ghez, A.M., Spencer, J. (2003). Speckle imaging of volcanic hotspots on Io with the Keck telescope Icarus, 165, 137 Noll, K.S., D.C. Stephens, W.M. Grundy, R.L. Millis, J. Spencer, M.W. Buie, S.C. Tegler, W. Romanishin, and D.P. Cruikshank 2002. Detection of two binary Trans-Neptunian objects, 1997 CQ 29 and 2000 CF 105 , with the Hubble Space Telescope. Astron. J., 124, 3424-3429. \ref Spencer, J.R. and W. M. Calvin 2002. Condensed O2 on Europa and Callisto. Astron. J. 124, 3400-3403. \ref Grundy, W.M., M.W. Buie, and J.R. Spencer 2002. Spectroscopy of Triton and Pluto at 3 - 4 microns: Possible evidence for wide distribution of nonvolatile solids. Astron. J. 124, 2273-2278. \ref Spencer, J.R. and 19 co-authors, 2002. The future of Io exploration. Community white paper for the Planetary Decadal Survey, in The Future of Solar System Exploration, 2003-2013 (M. Sykes, Ed.), Astron. Soc. Pac. Conference Series 270, 201-216. \ref Howell, R.R., J.R. Spencer, J. D. Goguen, F. Marchis, R. Prange, T. Fusco, D.L. Blaney, G.J. Veeder, J.A. Rathbun, G.S. Orton, A.J. Grocholsky, J.A. Stansberry, G.S. Kanner, E.K. Hege (2001). + Ground-based observations of volcanism on Io in 1999 and early 2000. + J. Geophys. Res.+ 106+, 33129-33139. \ref Menietti, J.D., D.A. Gurnett, J.R. Spencer, J.A. Stansberry (2001). + Relationship between Jovian hectometric radiation and Io volcanic activity.+ Radio Science+ 36,+ 1723-1731. \ref Meadows, V., D. Crisp, J. Barnes, G. Orton, J. Spencer (2001).+ AAT observations of the SL9 fragment C, D, G, K, N, R, V, and W impacts with Jupiter: Lightcurves and imaging.+ Icarus+ 152+, 366-383. \ref Spencer, J.R., J.A. Rathbun, L.D. Travis, L.K. Tamppari, L. Barnard, T.Z. Martin (2000). + Io's thermal emission from the Galileo Photopolarimeter-Radiometer. +Science+ 288+, 1198-1201. \ref Spencer, J.R., K. L. Jessup, M.A. McGrath, G.E. Ballester, and R. Yelle (2000).+ Discovery of gaseous S2 in Io's Pele plume. Science+ 288+, 1208-1210. \ref Sromovsky, L.A., J.R. Spencer, K.H. Baines, and P.M. Fry (2000).+ Ground-based observations of cloud features on Uranus. +Icarus+ 146+, 307-311. \ref McIntosh, B., D. Gavel, S. G. Gibbard, C. E. Max, M. Eckart, I. de Pater, A. M. Ghez, and J. Spencer (2000). +Speckle imaging of volcanic hotspots on Io with the Keck telescope.+ Icarus++, submitted. \ref McGrath, M.A., M.J.S. Belton, J.R. Spencer, and P. Sartoretti (2000).+ Spatially resolved spectroscopy of Io's Pele plume and SO2 atmosphere.+ Icarus+ 146+, 476-493. \ref Moore, J.M., E. Asphaug, D. Morrison, J.R. Spencer, C.R. Chapman, B. Bierhaus, R.J. Sullivan, F.C. Chuang, J.E. Klemaszewski, R. Greeley, K.C. Bender, P.E. Geissler, P. Helfenstein, and C.B. Pilcher (1999).+ Mass movement and landform degredation on the icy Galilean satellites: Results from the Galileo nominal mission. +Icarus +140,+ 294-312. \ref Grundy, W.M., M.W. Buie, J.A. Stansberry, J.R. Spencer, and B. Schmitt (1999). +Near-infrared spectra of icy outer solar system surfaces: Remote determination of of H$_2$O ice temperatures. +Icarus+ 142+, 536-549. \ref Lopes-Gautier, R., A.S. McEwen, W.D. Smythe, P.E. Geissler, L. Kamp, A.G. Davies, J.R. Spencer, L. Keszthelyi, R. Carlson, F.E. Leader, R. Mehlman, L. Soderblom, and the Galileo NIMS and SSI teams (1999).+ Active volcanism on Io: Global distribution and variations in activity.+ Icarus +140,+ 243-264. \ref Spencer, J.R., L.K. Tamppari, T.Z. Martin, and L.D. Travis (1999). +Temperatures on Europa from Galileo PPR: Nighttime thermal anomalies. +Science+ 284,+ 1514-1516. \ref Ortiz, J.L., G.S. Orton, A.J. Friedson, S.T. Stewart, B.M. Fisher, and J.R. Spencer (1998). + Evolution and persistence of 5-micron hot spots at the Galileo probe entry latitude.+ J. Geophys. Res.+103,+ 23051--23069. \ref McEwen, A.S., L. Keszthelyi, J.R. Spencer, G. Schubert, D.L. Matson, R. Lopes-Gautier, K.P. Klaasen, T.V. Johnson, J.W. Head, P. Geissler, S. Fagents, A.G. Davies, M.H. Carr, H.H. Breneman, and M.J.S. Belton (1998)+ Very high temperature volcanism on Jupiter's Moon Io.+ Science +281,+ 87-91. \ref Elliot, J.L., H.B. Hammel, L.H. Wasserman, O.G. Franz, S.W. McDonald, M.J. Person, C.B. Olkin, E.W. Dunham, J.R. Spencer, J.A. Stansberry, M.W. Buie, J.M. Pasachoff, B.A. Babcock, and T.H. McConnochie (1998).+ Global warming on Triton.+ Nature+ 393,+ 765--767. \ref Spencer, J. R. (1998). + Upper limits to the depth of condensed O2 absorption bands on the icy Saturnian satellites and Saturn's rings. +Icarus+ 136,+ 349--352. \ref Spencer, J. R., L. M. Trafton, J. A. Stansberry, E. F. Young, R. P. Binzel, and S. K. Croft (1997).+ Volatile transport, seasonal cycles, and atmospheric dynamics on Pluto. In +Pluto and Charon++(A. Stern and D. Tholen, Eds.), pp. 435--473. U. Arizona Press, Tucson. \ref Spencer, J. R., A. S. McEwen, M. A. McGrath, P. Sartoretti, D.B. Nash, K.S. Noll, and D. Gilmore (1997). + Volcanic resurfacing of Io: Post-repair HST imaging. +Icarus,+ 127,+ 221-237. \ref Spencer, J. R., J. A. Stansberry, C. Dumas, D. Vakil, R. Pregler, M. Hicks, and K. Hege (1997).+A History of High-Temperature Io Volcanism: February 1995 to May 1997.+Geophys. Res. Lett. +24,+2451--2454. \ref Spencer, J. R., P. Sartoretti, G. E. Ballester, A. S. McEwen, J. T. Clarke, and M. McGrath (1997). + The Pele plume (Io): Observations with the Hubble Space Telescope. +Geophys. Res. Lett. + 24,+ 2471-2474. \ref Stansberry, J. A., J. R. Spencer, R. R. Howell, C. Dumas, and D. Vakil (1997). +Violent Silicate Volcanism on Io in 1996.+ Geophys. Res. Lett.+ 24,+ 2455-2458. \ref Blaney, D., G. Veeder, D. Matson, T. Johnson, J. Goguen, and J. Spencer (1997). +Io's thermal anomalies: Clues to their origin from comparing ground based observations between 1 and 20 microns.+ Geophys. Res. Lett.+ 24,+ 2459--2462. \ref Calvin, W. M., and J.R. Spencer (1997). + Latitudinal distribution of O$_2$ on Ganymede: Observations with the Hubble Space Telescope. +Icarus,+ 130,+ 505-516. \ref Stansberry, J. A., J. R. Spencer, and J. C. Pearl (1997).+ Voyager 2 IRIS data revisited: Evidence for a low temperature and emissivity on Triton.+ J. Geophys. Res.,++ submitted. \ref Calvin, W. M., R. E. Johnson, and J. R. Spencer (1996).+ O2 on Ganymede: Spectral characteristics and plasma formation+ Geophys. Res. Lett.+ 23+ 673--676. \ref Bell, J.F., W. M. Calvin, M. E. Ockert-Bell, D. Crisp, J. B. Pollack, and J. Spencer (1996). + Detection and monitoring of H2O and CO2 ice clouds on Mars. + J. Geophys. Res. +101,+ 9227--9237. \ref Bus, S. J., and 18 co-authors including J. R. Spencer (1996).+ Stellar occultation by 2060 Chiron. +Icarus+ 123,+ 478--490. \ref Spencer, J. R. and N. M. Schneider (1996). +Io on the Eve of the Galileo Mission+ Ann. Rev. Earth Planet. Sci.+ 24+, 125--190. \ref Orton, G., and 37 co-authors including J. R. Spencer (1996).+ Preliminary results of earth-based observations of the Galileo probe entry site.+ Science+ 272,+ 839--840. \ref Stansberry, J. A., J. R. Spencer, B. Schmitt, A. Benchkoura, R. V. Yelle, and J. I. Lunine (1996).+ A model for the overabundance of methane in the atmospheres of Pluto and Triton.+ Planet. Space Sci.+ 44,+ 1051--1063. \ref Orton, G. S., J. R. Spencer, L. D. Travis, T. Z. Martin, and L. K. Tamppari (1996). + Galileo photopolarimeter-radiometer observations of Jupiter and the Galilean satellites.+ Science+ 274,+ 389--391. \ref Sartoretti, P., M.A. McGrath, A.S. McEwen, and J.R. Spencer (1995).+ Post Voyager Brightness Variations on Io. + J. Geophys. Res., +100,+ 7523--7530. \ref Spencer, J. R., W. M. Calvin, and M. J. Person (1995).+ CCD spectra of the Galilean satellites: Molecular oxygen on Ganymede.+ J. Geophys. Res.,+ 100,+ 19049--19056. \ref Spencer, J. R., and 49 co-authors (1995).+ The lightcurve of 4179 Toutatis: Evidence for complex rotation.+ Icarus +117,+ 71--89. \ref Calvin, W. M., R. N. Clark, R. H. Brown, and J. R. Spencer (1995).+ The icy Galilean satellites: New observations and a spectroscopic summary.+J. Geophys. Res. +100,+ 19041--19048. \ref Tamppari, L.K., J. R. Spencer, and T. Z. Martin (1995).+ Observing the icy Jovian satellites with the Galileo Photopolarimeter Radiometer instrument+ J. Geophys. Res.,+100,+ 18973--18983. \ref Spencer, J. R., B. E. Clark, L. M. Woodney, W. M. Sinton, and D. Toomey (1994).+ Io hot spots in 1991: Results from Europa occultation photometry and infrared imaging. +Icarus+ 107,+ 195-208. \ref Spencer, J. R., and J. M. Moore (1992).+ The influence of thermal inertia on temperatures and frost stability on Triton.+ Icarus,+99, +261-272. \ref Spencer, J. R., R. R. Howell, B. E. Clark, D. R. Klassen, and D. O'Connor (1992)+ Volcanic activity on Io at the time of the Ulysses encounter.+ Science,+257, +1507--1510. \ref Spencer, J.R. (1990).+ A rough surface thermophysical model for airless planetary surfaces. +Icarus+83,+ 27--38. \ref Spencer, J.R. and F.P. Fanale (1990).+ New models for the origin of Valles Marineris closed depressions. +J. Geophys. Res.+95,+ 14301--14313. \ref Spencer, J.R. (1990).+ Nitrogen frost migration on Triton: a historical model. +Geophys. Res. Lett.+17+ 1769--1772. \ref Moore, J.M., and J.R. Spencer (1990).+ Koyaanismuuyaw: the hypothesis of a perennially dichotomous Triton. +Geophys. Res. Lett.+17+ 1757--1760. \ref Spencer, J.R., M.W. Buie, and G.L. Bjoraker (1990).+ Solid methane on Triton and Pluto: 3--4 micron spectrophotometry. +Icarus,+88,+ 491-496. \ref Spencer, J.R., M.A. Shure, M.E. Ressler, J.D. Goguen, W.M. Sinton, D. W. Toomey, A. Denault, and J. Westfall (1990).+ Discovery of hotspots on Io using disk-resolved infrared imaging.+ Nature,+348+ 618--621. \ref Lebofsky, L.A. and J.R. Spencer (1989).+Radiometry and thermal modeling of asteroids. +Asteroids II++(R. Binzel, T. Gehrels, M. Matthews, Eds.), U. of Arizona Press, Tucson, 128--147. \ref Smith, B.A., L.A. Soderblom, 52 co-authors, J. Spencer, 10 more co-authors (1989).+Voyager 2 at Neptune: Imaging Science Results. +Science+246,+ 1422--1449. \ref Spencer, J.R., L.A. Lebofsky, and M.V. Sykes (1989).+Systematic biases in radiometric diameter determinations. +Icarus,+78,+ 337--354. \ref Spencer, J.R. (1987).+Icy Galilean satellite reflectance spectra: less ice on Ganymede and Callisto?+Icarus+70,+99--110. \ref Spencer, J.R. (1987).+Thermal segregation of water ice on the Galilean satellites.+Icarus+69,+297--313. \ref Spencer, J.R. and P.R. Maloney (1984).+Mobility of water ice on Callisto: evidence and implications.+Geophys. Res. Let.+11,+1223--1226. \headsecond IAU Circulars \ref Spencer J. R., J. E. B. Spencer, and D. Griep (1995).+ Jupiter I (Io) +Intl. Astron. Union Circular++ 6149. \ref Spencer J. R., J. E. B. Spencer, and D. Griep (1995).+ Jupiter I (Io) +Intl. Astron. Union Circular++ 6143. \ref Davies J., J. Spencer, M. Sykes, D. Tholen, and S. Green (1993).+ (5145) Pholus + Intl. Astron. Union Circular++ 5698. \headsecond Dissertation \ref Spencer, J.R. (1987).++The surfaces of Europa, Ganymede, and Callisto: an investigation using Voyager IRIS thermal infrared spectra.++Ph.D. Dissertation, University of Arizona. \headsecond Books \ref Spencer, J. R. and J. Mitton, eds. (1995).++The Great Comet Crash: The collision of Comet Shoemaker-Levy 9 and Jupiter++. Univ. Cambridge Press, Cambridge, UK. \headsecond Popular Articles \ref Spencer, J.R. (2001).+ Galileo's Closest Look at Io. +Sky and Telescope,++ May 2001, p. 40--45. \ref Spencer, J.R. (2000).+ An Exciting Year on Io. +Lowell Observer,++ Fall 2000, 3--4. \ref Spencer, J.R. (1999).+Io and I. In +Our Worlds,++ Alan Stern, ed., Cambridge University Press, Cambridge, UK. \ref Spencer, J.R. (1997).+Io and I. +Planetary Report+17,+\#4, 4--8. \ref Spencer, J.R. (1997).+Jupiter's odd bunch. +New Scientist+154,+\#2076, 42--45. \ref Spencer, J.R. (1996).+Jupiter at last! +Lowell Observer,++Summer 1996, 1--2. \ref Spencer, J.R. (1995).+Finding oxygen on a Jovian moon. +Lowell Observer,++Summer 1995, 3. \ref Spencer, J.R. (1994).+Observing a cataclysm: The last days of Comet Shoemaker-Levy 9. +Planetary Report+14,+\#3, 10--13. \ref Spencer, J.R. (1989).+Epilog for Voyager +Planetary Report+9,+\#6, 21. \ref Spencer, J.R. (1982).+Mars: the Viking legacy. +Planetary Report+2,+\#5, 10--14. \headsecond Abstracts, Presentations, etc. (Incomplete, and in reverse time order): \ref Schultz, P.H. and J.R. Spencer (1979).+Effects of substrate strength on crater statistics: implications for surface ages and gravity scaling (extended abstract)+Lunar and Planetary Science+10+ 1081--1083. \ref McKinnon, W.B. and J.R. Spencer (1981).+Tectonic deformation of Galileo Regio and limits to the planetary expansion of Ganymede. Extended abstract, presented at the 12th LPSC+Lunar and Planetary Science+12,+694--696. \ref Spencer, J.R. and P.R. Maloney (1981).+Evidence for mobility of water ice on Callisto. Abstract, presented at 13th DPS meeting, Pittsburg+Bull. Am. Astron. Soc.+13,+737--738. \ref Spencer, J.R. (1982).+Voyager stellar occultation by Ganymede: relevance to surface ice temperature and volatile transport. Abstract, presented at 14th DPS meeting, Boulder+Bull. Am. Astron. Soc.+14,+739. \ref Spencer, J.R. (1982).+Voyager Ganymede stellar occultation and surface ice temperatures. Extended abstract.+Reports of the Planetary Geology Program++NASA Tech.\ Memo.\ 85127, 32--34. \ref Strom, R.G., A. Woronow, and J.R. Spencer (1982).+Effects of the Orientale impact on the pre-existing crater population. Extended abstract.+Reports of the Planetary Geology Program++NASA Tech.\ Memo.\ 85127, 108--110. \ref Spencer, J.R. (1983).+Ganymede in the thermal infrared: preliminary analysis of Voyager IRIS data. Extended abstract, poster talk at 14th LPSC+Lunar and Planetary Science+14,+ 731--732. \ref Spencer, J.R. (1983).+Analysis of Voyager thermal infrared observations of Ganymede. Abstract, presented at IAU Colloquium on Natural Satellites , Ithaca, p.~25 of abstract volume.+++ \ref Spencer, J.R. (1983).+Surface properties of Ganymede as inferred from Voyager IRIS observations. Abstract, presented at 15th DPS meeting, Ithaca+Bull. Am. Astron. Soc.+15,+860--861. \ref Spencer, J.R. (1984).+A tectonic geomorphological classification of the walls of Valles Marineris. Extended abstract.+Reports of the Planetary Geology Program++NASA Tech. Memo. 86246, 243--245. \ref Spencer, J.R. (1984).+An ice-poor interpretation of Callisto's reflectance spectrum. Abstract, presented at 16th DPS meeting, Kona+Bull. Am. Astron. Soc.+16,+685. \ref Spencer, J.R. and S.K. Croft (1985).+Valles Marineris as karst: feasibility and implications for Martian atmospheric evolution. Extended abstract, presented at MECA Workshop on the Evolution of the Martian Atmosphere, Honolulu+LPI Technical Report+86-07+40--41. \ref Spencer, J.R. (1985).+Differences in the thermal emission of Ganymede and Callisto. Abstract, presented at 17th DPS meeting, Baltimore+Bull. Am. Astron. Soc.+17+693. \ref Spencer, J.R. (1987).+A rough-surface model of Callisto's thermal emission. Abstract, presented at 19th DPS meeting, Pasadena+Bull. Am. Astron. Soc.+19+861. \ref Spencer, J.R. (1988).+A realistic asteroid thermal model, including the effects of surface roughness and thermal inertia. Abstract, presented at the Asteroids II meeting, Tucson.+++ \ref Spencer, J.R., and M.W. Buie (1988).+First 3--4 micron observations of Triton and Pluto. Abstract, presented at 20th DPS meeting, Austin+Bull. Am. Astron. Soc.+20+810. \ref Spencer, J.R. (1988).+The thermal inertias and albedos of Rhea and Tethys. Abstract, 20th DPS meeting, Austin+Bull. Am. Astron. Soc.+20+854. \ref Spencer, J.R., F.P. Fanale, and J.E. Tribble (1989).+Karst on Mars? Origin of closed depressions in Valles Marineris by solution of carbonates in groundwater sulfuric acid. Abstract, presented at the 4th International conference on Mars, Tucson.+++ \ref Spencer, J.R. (1989).+Asteroid thermal phase curves, and other evidence for very low thermal inertia asteroid surfaces. Abstract, presented at Asteroids, Comets, Meteors III, Uppsala, Sweden.+++ \ref Spencer, J.R. (1989).+The thermal inertias of Rhea, Dione, and Tethys from ground-based radiometry. Abstract, presented at the 21st DPS meeting, Providence. +Bull. Am. Astron. Soc.+21,+983. \ref Spencer, J.R., M.A. Shure, M.E. Ressler, D.Toomey, A. Denault, W.Sinton, and J.D. Goguen (1990).+ Disk-resolved ground based infrared imaging of Io. Abstract, presented at the 21st LPSC.+Lun. Plan. Sci.+21+ 1182--1183. \ref Spencer, J.R., M.A. Shure, M.E. Ressler, W.Sinton, A. Denault, D.Toomey, J.D. Goguen, and J. Westfall (1990).+ Disk-resolved ground based IR imaging of Io: Loki and two new hot spots. Abstract, presented at the 22nd DPS meeting, Charlottesville. +Bull. Am. Astron. Soc.+22+ 1108--1109. \ref Goguen, J.D., J.R. Spencer, M.A. Shure, M.E. Ressler, D.Toomey, and C. Kaminski (1990).+ The spatial distribution of volatiles and location of active hot spots on Io from ground-based IR images. Abstract, +Bull. Am. Astron. Soc.+22+ 1108--1109. \ref Spencer, J.R., D. Toomey, and C. Kaminski (1991).+ Jupiter's occultation of Io's hot spots. Cover photo and caption in+EOS,+72,+ 33. \ref Spencer, J.R. (1991).+ The nature of Io's volcanic activity: Constraints from ground-based infrared observations. Abstract, invited talk at AGU Spring Meeting, Baltimore.+EOS,+ 72,+185. \ref Spencer, J.R., W. Sinton, C. Oppenheimer, C. Kaminski, and D. Rothery (1991).+High-Temperature volcanic thermal emission: from Io to the Andes. Abstract, +Bull. Am. Astron. Soc.+23,+ 1227. \ref J. D. Goldader, D. J. Tholen, T. Herbst, W. Golisch, J. R. Spencer, D. P. Cruikshank, and W. K. Hartmann (1991).+ 951 Gaspra: Results from observations spanning two oppositions. Abstract, +Bull. Am. Astron. Soc.+23,+ 1142. \ref Spencer, J.R., and J. Moore (1992).+ The influence of surface thermal inertia on Triton's volatile distribution. Abstract, presented at the Neptune and Triton conference, Tucson, Arizona.+++ \ref Spencer, J. R., B. E. Clark, D. O'Connor, and W. M. Sinton (1992).+ Variablility of Thermal Emission from Individual Io Hot Spots, 1989 - 1992. Abstract, presented at the ``Time Variable Phenomena in the Jovian System'' meeting, Annapolis, MD, July 1992.+++ \ref Spencer, J. R., B. E. Clark, and L. Woodney (1992).+ Io hot spot imaging in 1991/1992: It's been a quiet year at Loki Patera.+ Abstract, Bull. Am. Astron. Soc.+ 24,+ 935. \ref Tholen, D. J., and J. R. Spencer (1992).+ Close encounters of the asteroidal kind: A preview of upcoming encounters with 243 Ida and 4179 Toutatis. Abstract,+ Bull. Am. Astron. Soc.+ 24,+ 934. \ref Spencer, J. R., J.P. Emerson, D.J. Tholen, C. Skinner, M. Meixner, J. Graham, D. Walther, A. Ghez, H. Campins, D. Osip, G. Rieke, and M. Rieke (1993). +The thermal emission of 4179 Toutatis from 150 to 6 degree phase angle. Abstract, presented at IAU Symposium 160, ``Asteroid, Comets, and Meteors 1993'', Belgirate, Italy, June 1993.+++ \ref Noll, K.S., B. Zellner, H. Weaver, A. Storrs, J. Spencer, A. Whipple, and D. Tholen (1993). + Imaging of asteroid 4179 Toutatis with the Hubble Space Telescope. Abstract, presented at IAU Symposium 160, ``Asteroid, Comets, and Meteors 1993'', Belgirate, Italy, June 1993.+++ \ref Spencer, J. R., and W.M. Calvin (1993).+ CCD spectra of Io. Abstract, presented at ``Io: an International Conference'', San Juan Capistrano, June 1993.+++ \ref Spencer, J. R., C. Dumas, B.E. Clark, and W.M. Sinton (1993).+ Infrared imaging of Io: Volcanic activity 1989--1993. Abstract, presented at ``Io: an International Conference'', San Juan Capistrano, June 1993.+++ \ref Spencer, J. R., T.Z. Martin, and L.K. Tamppari (1993).+ Galileo PPR observations of Io: Science goals and plans. Invited review and abstract, presented at ``Io: an International Conference'', San Juan Capistrano, June 1993.+++ \ref Spencer, J.R., L. Trafton, J.A. Stansberry, E.F. Young, and R.P. Binzel (1993).+ Dynamics, volatile transport, and seasonal cycles on Pluto. Invited review and abstract, presented at the ``Pluto and Charon'' conference, Flagstaff, July 1993.+++ \ref Spencer, J. R., and W. M. Calvin (1993).+ CCD spectra of the Galilean satellites: a narrow non-ice feature on Ganymede. Abstract,+ Bull. Am. Astron. Soc. + 25,+ 1114. \ref Dumas, C., Spencer, J. R., L. Woodney, A. Angara, and B. Clark (1993).+ Fourier deconvolution of Io infrared images: a new step in the survey of Io's volcanic activity. Abstract,+ Bull. Am. Astron. Soc. + 25,+ 1073. \ref Stansberry, J.A., J. Spencer, and J. Lunine (1993).+ Evolution of volatile solid solutions on Triton and Pluto. Abstract,+ Bull. Am. Astron. Soc. + 25,+ 1130. \ref Spencer, J. R. (1994). + Thermal properties of the icy Galilean satellites. +++Invited review and abstract, presented at the ``Icy Galilean Satellites Conference'', San Juan Capistrano, February 1994. \ref Spencer, J. R. and W. M. Calvin (1994). + CCD Spectra of the Galilean satellites: a narrow non-ice absorption feature on Ganymede. +++Abstract, presented at the ``Icy Galilean Satellites Conference'', San Juan Capistrano, February 1994. \ref L.K. Tamppari, T.Z. Martin, and J. Spencer (1994). + Observing the icy jovian satellites with the Galileo photopolarimeter/radiometer instrument. +++Abstract, presented at the ``Icy Galilean Satellites Conference'', San Juan Capistrano, February 1994. \ref Spencer, J. R. (1994). + Observing a cataclysm: the last days of comet Shoemaker-Levy 9. + Planetary Report ++, May 1994 issue. \ref Spencer, J. R., A. S. McEwen, M. A. McGrath, and P. Sartoretti (1994). +Post-Repair HST Imaging of Io's Surface and Volcanism.+ EOS + 75,+ 218. \ref Depoy, D. L., J. R. Spencer, G. S. Orton, C. Dumas, and S. J. Kim (1994). + Near-IR observations of the comet crash from Cerro Tololo. DPS Abstract,+ Bull. Am. Astron. Soc.+ 26,+ 1593. \ref Kim, S., C. Dumas, G. Orton, T. Brooke, and J. Spencer (1994).+ Spectroscopic study of the SL9 impact areas of Jupiter with the CTIO IRS.+ Bull. Am. Astron. Soc.+ 26,+ 1582. \ref Sromovsky, L. A., P. M. Fry, H. B. Hammel, J. R. Spencer, and M. Shure (1994).+ Cloud features in 1993 image of Neptune at 1.6 and 2.2 microns. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1095. \ref Spencer, J. R., M. A. McGrath, P. Sartoretti, and A. S. McEwen (1994).+ Post-repair HST imaging of Io: Surface changes and spectral anomalies. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1135. \ref Calvin, W. M., and Spencer, J. R. (1994).+ Identification of O$_2$ on Ganymede. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1159. \ref Sauter, L. M., N. M. Schneider, and J. R. Spencer (1994).+ Search for [SI] emission from Io's atmosphere. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1138. \ref Marcialis, R. L., and 21 co-authors including J. R. Spencer (1994).+ The 1993 Nov 07 occultation of Ch02 by Charon. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1153. \ref Calvin, W. M., and J. R. Spencer (1994).+ Identification of O2 on Ganymede. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1159. \ref Pisano, D. J., J. A. Stansberry, and J. R. Spencer (1994).+ The emissivity of N2 ice: Hapke theory. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1177. \ref Stansberry, J. A., J. R. Spencer, and J. C. Pearl (1994).+ Triton's temperature and emissivity: Voyager IRIS data revisited. DPS Abstract,+ Bull. Am. Astron. Soc.,+ 26+ 1177. \ref Spencer, J. R., D. L. Depoy, G. S. Orton, C. Dumas, and S. J. Kim (1995),+ Near IR images and spectra of the impact sites from Cerro Tololo. Abstract, presented at IAU colloquium 156, +The Collision of Comet P/Shoemaker-Levy 9 and Jupiter,++ Baltimore, May 1995. \ref Spencer, J. R., A. S. McEwen, D. B. Nash, M. A. McGrath, J. T. Clarke, G. E. Ballester, P. Sartoretti, and J. T. Trauger (1995). + A major albedo change on Io in 1994-1995.+ Bull. Am. Astron. Soc.+ 27,+ 1160. \noindent Only selected recent abstracts are included. \ref Spencer, J. R., G. E. Ballester, P. Sartoretti, A. S. McEwen, J. T. Clarke, M. McGrath (1997). + Observations of the Pele plume (Io) with the Hubble Space Telescope. + Bull. Am. Astron. Soc.+29,+ 1001. \ref Stansberry, J. A., J. R. Spencer, R. R. Howell, and C. Dumas (1997). +Thermal models and 1-5 micron photometry: Spring 1997 Loki brightening. + Bull. Am. Astron. Soc.+29,+ 978. \ref Howell, R.R., J. R. Spencer, and J. A. Stansberry (1997).+ The 1997 mutual event occultations of Io.+ Bull. Am. Astron. Soc.+29,+980. \ref Spencer, J. R., L. K. Tamppari, T. Z. Martin, and L. D. Travis (1997).+ Galileo PPR thermal observations Io.+ Abstract, presented at the +Io During the Galileo Era++ meeting, Flagstaff, AZ. \ref Spencer, J. R., A. S. McEwen, P. Sartoretti, G. Ballester, M. McGrath, and D. Nash (1997).+ Hubble Space Telescope observations of plumes and surface changes on Io.+ Abstract, presented at the +Io During the Galileo Era ++meeting, Flagstaff, AZ. \ref Spencer, J. R., L. K. Tamppari, T. Z. Martin, and L. D. Travis (1997).+ Thermal observations of the Galilean satellites with the Galileo Photopolarimeter-Radiometer (PPR).+ Invited abstract, presented at the +Fall AGU meeting, ++ San Francisco. \ref Spencer, J. R. (1998).+ Researchers focus attention on remarkable Io, +Eos Transactions + 79,+ 100. \ref Spencer, J. R., L. Prockter, R. Pappalardo, J. Head, J. Moore, and the Galileo SSI Team (1998).+ Local volatile migration on Ganymede: Galileo SSI images, PPR radiometry, and theoretical considerations.+ Abstract, presented at + Lunar \& Planet. Sci. Conf. XXIX,++ Houston, Texas. \ref Stansberrry, J. A., J. R. Spencer, R. R. Howell, T. L. Hudson (1998). +The 1997 Loki eruption: Groundbased observations. Abstract, presented at + Lunar \& Planet. Sci. Conf. XXIX,++ Houston, Texas. \ref Moore, J. M., J. R. Spencer, E. Asphaug, D. Morrison, J. E. Klemaszewski, R. J. Sullivan, F. C. Chuang, R. Greeley, K. C. Bender, P. E. Geissler, C. R. Chapman, C. B. Pilcher, and the Galileo SSI team (1998).+ Mass movement and landform degredation on Callisto and Ganymede as observed during the Galileo nominal mission: the role of sublimation. Abstract, presented at + Lunar \& Planet. Sci. Conf. XXIX,++ Houston, Texas. \end