Earth-Based Support for the New Horizons Kuiper Extended Mission. Richard Binzel Alan Stern John Spencer 2016 DPS Meeting, Pasadena October18 th 2016

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1 Earth-Based Support for the New Horizons Kuiper Extended Mission Richard Binzel Alan Stern John Spencer 2016 DPS Meeting, Pasadena October18 th 2016

2 Agenda Introduction to New Horizons Kuiper Belt Extended Mission (KEM) - Alan Stern Overview of KEM Observations John Spencer Supporting Groundbased Priorities Rick Binzel Occultation Opportunities Amanda Zangari Discussion - All 2 Please complete the signup sheet!

3 2014 MU 69 Orbit is typical for cold classical KBO (prob. kernel) Thus likely to be red, relatively low albedo Unlikely to resemble small Pluto satellites in origin or composition However we know little about CCKBOs in this size range Opposition in 2016: July 5 th HST discovery images 3 Note: JPL Horizons gives opposition V magnitude incorrectly as 25.4

4 MU69 Size Currently unknown: depends on albedo Typical KBO albedos are in the range , corresponding to diameters of km Below break-in-slope of KBO size-frequency distribution Primordial body smaller than preferred accretion size? Product of collisional fragmentation? Chance to determine size via stellar occultations in summer 2017 Very challenging, due to narrowness of occultation shadow Cold Classicals Hot KBOs Jupiter Trojans Fraser et al. (2014) 2014 MU 69

5 MU69 Rotation Period Period currently unknown Typical KBO rotation periods are in the range 4 24 hours Lightcurve amplitude < ~factor of two HST program (Susan Benecchi, PI) will attempt determination of the rotation period and lightcurve amplitude with 24 orbits of HST time in summer 2017 Depending on the result, it may be possible or desirable to use fuel on approach to MU69 to arrive near lightcurve maximum, to maximize illuminated pixels

6 MU69 Color Recently constrained using HST (Susan Benecchi, PI) Uncertainties are large, but consistent with red color of other cold classical KBOs Approximate Diameter (km) Red Diamond = Classical Gray Square = All other Classes Black Circle = New Horizons KBOs 2013 LU35 F606W-F814W JW HE HF JY HK HZ OS PN MU Pluto Color Solar Color F606W

7 Nominal Strawman MU69 Close Encounter Sequence Strawman 3000 km c/a distance (subject to change) Visible imaging, many phase angles, up to 25 m/pixel Near-IR compositional maps ~1.0 km/pixel Color imaging, ~0.5 km/pixel FUV/EUV observations to search for outgassing REX disk-integrated day and night thermal emission Distance Perpendicular to Trajectory, km -10, CA01_Alice K s Sun Direction Direction of motion CA02_LEISA CA02_LORRI CA03_LEISA CA03_Alice K s CA04_REX CA04_Alice CA05_MVIC COL CA05_LORRI CA06_LEISA CA06_LORRI K s CA07_LORRI MU69-40,000-30,000-20,000-10, ,000 20,000 Distance Along Trajectory, km CA08_MVIC PAN CA08_LORRI K+ 0 s CA09_MVIC PAN CA09_LORRI CA10_REX CA10_Alice K s CA11_LORRI CA12_Alice

8 Currently uses a 10,000 km close approach, +/- 12,000 km position uncertainty May change with further analysis C/A = km, TOF err = 840 s 4 Backup Strawman MU69 Close Encounter Sequence MU CA01_Alice CA02_LEISA CA02_LORRI CA03_LEISA CA03_Alice CA04_REX CA04_Alice CA05_MVIC CA05_LORRI COL Sun Direction CA06_LEISA CA06_LORRI CA07_LORRI CA08_MVIC CA08_LORRI PAN CA09_MVIC CA09_LORRI PAN CA10_REX CA10_Alice CA11_LORRI CA12_Alice 0 K s K s K s K+ 0 s K s 0,000-30,000-20,000-10,000 Backup sequence and trajectory covers multiple contingencies: Hazard detection on approach Discovery of multiple bodies best studied at greater range Larger than expected navigational uncertainties Can decide to implement as late as K-16 days Distance Perpendicular to Trajectory, km 0-10,000 CA01_Alice K s CA02_LEISA CA02_LORRI Sun Direction CA03_LEISA CA03_Alice K s CA04_REX CA04_Alice CA05_MVIC COL CA05_LORRI Nominal strawman plan, to same scale CA06_LEISA CA06_LORRI K s CA07_LORRI MU69-40,000-30,000-20,000-10, ,000 20,000 Distance Along Trajectory, km CA08_MVIC PAN CA08_LORRI K+ 0 s CA09_MVIC PAN CA09_LORRI CA10_REX CA10_Alice K s CA11_LORRI CA12_Alice 8

9 Best Imaging in Strawman Sequence: Phobos-Based Simulation Assumes diameter of 32 km Includes expected SNR 9

10 Distant KBO Science Goals Distant (0.1 several AU) flybys of ~20 KBOs from ranges and geometries unobtainable from Earth Imaging with resolution better than HST in many cases, to search for satellites or unexpected phenomena (rings??) Lightcurves as a function of phase/aspect angle to constrain shapes and pole orientations Phase curves to constrain surface textures Phase curves can be compared to MU69 as a test of how typical MU69 is Including high phase angle searches for forward-scattering rings Possible vis/uv stellar occultations/appulses to search for rings, outgassing Possible mutual events of binary KBOs (none identified so far) 10

11 Distant KBO/Centaur Science Blue bars = planned 3-axis periods 24 objects in current plan Science Goals Multiple phase angles for phase coefficients 11 High phase angle photometry to search for forward-scattering rings Lightcurves from multiple viewpoints for shapes, rotation periods, pole positions Deep (4x4 binned) and hi-res (1x1, unbinned, up to 75 km/pixel) imaging for satellite and ring searches No color or NIR observations (all are too faint for MVIC color or LEISA) UV or visible occultations, if suitable opportunities are found Mutual events of binary systems, if suitable opportunities are found

12 Distant KBO/Centaur Science 4x4 LORRI limiting magnitude ~20 1x1 LORRI limiting magnitude ~16, with large numbers of coadds 12

13 Distant KBO Example Results So Far Plutino (15810) 1994 JR1, observed Nov 2015 and April 2016 First high phase observations of a KBO (up to 58 degrees) Phase curve fit indicates a rough surface Lightcurve gives first measurement of the rotation period (5.5 hours) Astrometry constraints orbital evolution 13

14 What We Need Astrometry of 2014 MU 69 and distant targets for orbit refinement and targeting Includes refinement of astrometric nets using Gaia and possibly additional starfield observations Earth-based occultations of MU69 (or other targets) Discovery and orbit refinement of binary KBOs to aid in search for NH mutual event opportunities Discovery of additional KBOs close enough or bright enough for useful NH observations (most useful in 2017) 14

15 What We Need Earth-based rotational lightcurves and periods For comparison with NH lightcurves for shape / pole orientation modeling and rotational correction of phase curves For bright KBOs with well-determined lightcurves, would like to know rotational phase at time of NH observations Rotation periods are valuable, especially in 2017, for design of most efficient spacecraft observations Absolute photometry for phase curves Colors (New Horizons observations of distant KBOs will be panchromatic only) For intrinsic value, and color corrections for phase curves Observations of other small KBOs to provide context for 2014 MU 69 and other targets 15

16 Challenges Most objects needing observations are fainter than R = MU 69 is R ~ 26.8 (don t believe Horizons!) Exception: Rotational lightcurves of bright KBOs Crowded star backgrounds for most objects But improving with time 16

17 Ready for an Update 4

18 Target List and Priorities 5

19 Known Programs Proposal Lead Facility Obs Type Description Buie HST MU69 Astrometry Approved long-term Benecchi HST MU69 Photometry Rotation period and lightcurve amplitude Porter Keck MU69 Astrometry / Not awarded photometry Kavelaars Gemini South MU69 Astrometry Weathered out Tanga Gaia Reference frame Astrometry Release expected 14 September Gurwell / Butler ALMA considered MU69 detection Estimate 25 days and not practicable. E. Young SOFIA MU69 Occultations Proposal submitted? Gurwell / Butler ALMA Pluto CO+HCN Pluto Thermal Map Submitted, pending Submitted, pending Benecchi / Lisse Kepler K2 (Campaign 7) Pluto high precision photometry >3000 measurements delivered! 6

20 MU69 Stellar Occulta/ons

21 Three Occulta/ons, Three Campaigns SOFIA Campaign Portable Campaign contact Eliot Young Debris and satellite campaign contact Amanda Zangari Need GAIA update to MU69 and proper mo/ons. Occulta/ons are on Earth. Looking for collaborators proposals at SOAR, (all) IRTF (July 10)

22 Three%MU69%occulta/ons% These paths subject to update from ongoing astrometry measurements and reduc6ons. For predic6on status, contact: NH G by 14MU /06/03 03:15:59 RA: DEC: Ephemeris corrections: s 0.000as Asteroid V: Computed R: Star R: Drop in R: Diam: 75.0 = 0.002as Max Duration: 3.7s Q: 82.1 Solar elongation: Lunar elongation: Illuminated: 66.3% Sun altitude at shown dotted Ticks from: 03:11:00 to 03:21:00 every 1 min NH G by 14MU /07/17 03:53:21 RA: DEC: Ephemeris corrections: s 0.000as Asteroid V: Computed R: Star R: Drop in R: Diam: 75.0 = 0.002as Max Duration: 3.1s Q: 81.8 Solar elongation: Lunar elongation: Illuminated: 46.2% Sun altitude at shown dotted Ticks from: 03:49:30 to 03:57:30 every 30 sec Paths shown are the status as of 2016 October 18

23 Discussion