New Horizons at Io: Science Goals and Observation

Plan

John SpencerJohn SpencerSwRI SwRI

Jeff Moore, Jeff Moore, NASA-AmesNASA-Ames

Debi RoseDebi Rose

and the and the New Horizons teamNew Horizons team

Io WorkshopIo WorkshopRedlands, June 6Redlands, June 6thth 2006 2006

Remote Sensing Instrument Suite

Closest approach (~32 RClosest approach (~32 RJJ):):InstrumentInstrument ResolutionResolution

, rad, radResolution, Resolution, km/pixkm/pix

Pixels Pixels across Ioacross Io

MVIC (0.48, 0.62, MVIC (0.48, 0.62, 0.85, 0.89 micron 0.85, 0.89 micron color imaging)color imaging)

2e-52e-5 4545 8181

LORRILORRI(0.4-1.0 micron (0.4-1.0 micron panchromatic panchromatic imaging)imaging)

5e-65e-6 1111 325325

LEISALEISA(1.25-2.5 micron (1.25-2.5 micron spectra)spectra)

6.2e-56.2e-5 139139 2626

ALICEALICE(0.05 – 0.18 (0.05 – 0.18 micron spectra)micron spectra)

5e-35e-3 1100011000 < 1< 1

Range vs. time

Phase vs. Time

Sub-S/C Longitude vs. Time

DSN Plan near Closest Approach

Science Overview

Observation CategoriesObservation Categories• Jupiter AtmosphereJupiter Atmosphere• IoIo• Icy Galilean SatellitesIcy Galilean Satellites• MagnetosphereMagnetosphere• RingsRings• Small SatellitesSmall Satellites• SceneryScenery

Io: Surface

Surface albedo changes since Surface albedo changes since GalileoGalileo• Global panchromatic LORRI Global panchromatic LORRI

coverage at ~12 km/pix (coverage at ~12 km/pix (Ihires01 Ihires01 – 06– 06))

• MVIC color coverage of Jupiter-MVIC color coverage of Jupiter-facing hemisphere at ~60 km/pix facing hemisphere at ~60 km/pix ((Ishine01, 02)Ishine01, 02)

Global topography from limb fitsGlobal topography from limb fits• Better longitude coverage than Better longitude coverage than

Galileo(?)Galileo(?) Nature of the broad 1.2 Nature of the broad 1.2 μμm m

absorption band? Global absorption band? Global distribution of 1.98, 2.12 distribution of 1.98, 2.12 μμm SOm SO22 bands? bands? • Global 1.25 – 2.5 Global 1.25 – 2.5 μμm reflectance m reflectance

spectroscopy (spectroscopy (Ihiresir01 – 04Ihiresir01 – 04))

Io: Plumes

Distribution, morphology, lifetime, Distribution, morphology, lifetime, short-term variability, and particle short-term variability, and particle size distribution of the plumessize distribution of the plumes• Global panchromatic LORRI Global panchromatic LORRI

coverage for plumes higher than coverage for plumes higher than ~60 km at high phase angles ~60 km at high phase angles ((Initemon01 – 14Initemon01 – 14))

• Color MVIC images of selected Color MVIC images of selected plumes (e.g. Pele, Prometheus, plumes (e.g. Pele, Prometheus, Tvashtar) on the limb (Tvashtar) on the limb (Ihires01, 05, Ihires01, 05, Initemon05, Ieclipse05Initemon05, Ieclipse05))

Short-term plume variability: Short-term plume variability: correlation of plumes with Jovian correlation of plumes with Jovian dust streams?dust streams?• Multiple LORRI observations of the Multiple LORRI observations of the

same longitudes on approach and same longitudes on approach and departure, with an emphasis on departure, with an emphasis on Pele (Pele (Isunmon01 – 09, Initemon01 Isunmon01 – 09, Initemon01 – 14– 14))

Io: Hot Spots

Temperatures and global distribution of the Temperatures and global distribution of the hottest hot spots? Temperatures constrain hottest hot spots? Temperatures constrain the magma compositionthe magma composition• Global eclipse and nightside imaging (Global eclipse and nightside imaging (Ieclipse01 Ieclipse01

– 05, Ihiresir04, Ishine01, 02– 05, Ihiresir04, Ishine01, 02)) • LORRI (0.4 – 1.0LORRI (0.4 – 1.0μμm panchromatic, ~12 km resolution) m panchromatic, ~12 km resolution) • MVIC (0.4 – 1.0 MVIC (0.4 – 1.0 μμm, ~50 km resolution)m, ~50 km resolution)• LEISA (1.25 – 2.5 LEISA (1.25 – 2.5 μμm, ~150 km resolution)m, ~150 km resolution)

Io in eclipse, 2.2 Io in eclipse, 2.2 μμm, 100 km resn, de Pater et al. 2004m, 100 km resn, de Pater et al. 2004

Io: Auroral Emissions Interaction of Io’s atmosphere with the Interaction of Io’s atmosphere with the

Jovian plasmaJovian plasma• ~40 Alice spectra of FUV neutral O, S ~40 Alice spectra of FUV neutral O, S

emissions at many geometries (emissions at many geometries (every Io every Io visitvisit))

• Eclipse imaging of visible SOEclipse imaging of visible SO22, O, S, Na , O, S, Na emissions (emissions (Ieclipse01 – 05Ieclipse01 – 05))

Thermal excitation of volcanic gasesThermal excitation of volcanic gases• Eclipse imaging of 1.7 Eclipse imaging of 1.7 μμm SO emission m SO emission

((Ieclipse01 – 05Ieclipse01 – 05))

Io: Neutral bound atmosphere

Does Io’s atmosphere collapse at night?Does Io’s atmosphere collapse at night?• Occultation of HD166052 (Occultation of HD166052 (Iocc01Iocc01, -2.1 days), -2.1 days)

• 5555oo S latitude S latitude• Phase angle 25Phase angle 25oo: see atmosphere at 7:40 am and 7:40 pm: see atmosphere at 7:40 am and 7:40 pm• Bright star: excellent S/N, strong absorption expectedBright star: excellent S/N, strong absorption expected• First ever observation of Io’s nightside atmosphereFirst ever observation of Io’s nightside atmosphere

• Occultation of HD211802 (Occultation of HD211802 (Iocc02Iocc02, -0.0 days), -0.0 days)• EquatorialEquatorial• Phase 87Phase 87oo: Noon/midnight: Noon/midnight• Very low S/NVery low S/N

Limb transmission, 1.6 x 10Limb transmission, 1.6 x 101616 cm cm-2-2 SO SO2 2 Star counts in bottom scale heightStar counts in bottom scale height

Simulated Occultation of V4387 SgrSimulated Occultation of V4387 Sgr

Io Observation Sequence

Io Color and Near-IR Hi-Res Longitudinal Coverage

Emission angle < 70Emission angle < 70oo

MVIC (yellow): ~50 km pixelsMVIC (yellow): ~50 km pixels LEISA (blue=dayside, orange=nightside): ~170 km pixelsLEISA (blue=dayside, orange=nightside): ~170 km pixels

Plume coverage

Height > 30 km, phase > 102Height > 30 km, phase > 102

Plume coverage

Height > 85 km, phase > 102Height > 85 km, phase > 102

Expected S/N

Generally use minimum integration time to avoid smear Generally use minimum integration time to avoid smear (except for auroral emissions).(except for auroral emissions).

Sensitivity is excellent anyway…Sensitivity is excellent anyway…

Expected S/NExpected S/N LORRI(0.1 sec)

MVIC(1000 murad/sec)

LEISA(450

murad/sec)

Target Blue Red CH4 NIR 1.2µm 2.5µm

“Bright Pele” hot spot 204 0.5 43 93 170 40 Satn.

“Faint Pele” hot spot 119 0.2 21 51 98 17 125

“Hot Pillan” hot spot 219 1.6 59 103 190 55 Satn.

Faint Plume, I/F=2e-4 5

Io in Jupiter shine, I/F=5.6e-3 62 130 60 130

Kodak Moments

What are the scenic What are the scenic properties of the properties of the Jupiter system?Jupiter system?

• LORRI images of LORRI images of selected scenic selected scenic conjunctions and conjunctions and alignments of the alignments of the satellites satellites ((Jkodak01, 02, Jkodak01, 02, Ikodak01, Ikodak01, Ekodak01, Ekodak01, Gkodak01, Gkodak01, Ckodak01Ckodak01))

Groundbased support

IRTF observations of IRTF observations of volcanos, starting in volcanos, starting in August 2006 (gap from August 2006 (gap from early October to late early October to late December)December)

Applied for VLT time for Applied for VLT time for high spatial resolution high spatial resolution volcano imaging and volcano imaging and plume spectroscopy plume spectroscopy near c/a in February near c/a in February 20072007