Using Spitzer to Observe the Solar System

Transcription

1 Using Spitzer to Observe the Solar System Sean Carey Spitzer Science Center 47 th DPS meeting 09 November 2015 SJC - 1

2 Spitzer Space Telescope NASA s Infrared Great Observatory Launched on 25 August 2003 Solar Orbit -- Earth trailing 85 cm telescope Calibrated data products provided through archive Post-cryo mission started 27 July 2009 Operate as a general observatory through 2018 until JWST launches Solar system science 10% of last observing cycle Exoplanets 25% of warm observations Potentially useful in more directed science plan for th DPS meeting 09 November 2015 SJC - 2

3 Cycles Exoplanets Brown Dwarfs Galac3c Structure Star Forma3on & Debris Disks Young Stellar Object Variability Compact Objects & Evolved Stars Distant Universe & Cosmology Nearby Galaxies Galaxy Clusters AGN/ ULIRGS Solar System Objects Transient Universe

4 Solar System Programs Selected for Cycle 11 PID Science Category Hours PI Ins4tu4on NEOs David Trilling NAU An Explora+on Science Survey of Near Earth Object Proper+es Comets Michael Kelley Maryland CO2 Orbital Trends in Comets Asteroids 50.0 Ben Rozi3s Tennessee Thermal Emission Light-Curves of Rapidly Rota+ng Asteroids Asteroids 22.2 Eric MacLennan Tennessee Regolith Size Sor+ng on Q-type NEAs KBOs 6.5 Noemi Pinilla-Alonso Tennessee Rota+onally resolved study of the surface of Pluto during NASA New Horizons flyby Satellites 5.1 Richard Cartwright Tennessee North Polar Surfaces of the Uranian Moons: Coated with CO2 Frost? Comets 1.6 Ma]hew Knight Lowell Obs. P/1999 R1: Sunskir+ng comet or asteroid? hours selected (15 props, hrs submitted) Three are led by new Spitzer PIs 47 th DPS meeting 09 November 2015 SJC - 4

5 Spitzer as Solar System Investigator Passive cooled operations at 3.6 and 4.5 µm using InfraRed Array Camera (IRAC) 5 arcmin FOVs ~1.6 arcsec resolution 1σ sensitivities in 100s are 21.2, 20.4 at 3.6 and 4.5 µm Saturate at 2 mag Solar system science built into observatory Track at 1 arcsec / second Moving target support in observing mode 47 th DPS meeting 09 November 2015 SJC - 5

6 Spitzer Orbit 1.50 AU! circle of radius 1 AU from Sun 0.50 AU! Earth Oct 2018 Nov 2016! Cryogen Depleted IOC/SV Mission Lifetime Req't Thru Cryo Depletion Warm Mission Distance from Earth and geometry modify spacecraft heating, battery charging and downlink rates 6 47 th DPS meeting 09 November 2015 SJC - 6

7 Spitzer Capabilities Unique vantage point with respect to Earth (currently 1.4 AU away) Different path length through Zodiacal dust cloud (could possible use shutter for Zody) Different viewing angle for NEAs ~7000 hours/year available for science observations Can observe continuously for ~72 hours Can observe targets quasi-continuously for 38 or more days (Need 2-4 hours gaps for downlinks every hours) 47 th DPS meeting 09 November 2015 SJC - 7

8 Spitzer Target Visibilities 47 th DPS meeting 09 November 2015 SJC - 8

9 Long-term Photometric Stability Absolute photometry stable to <0.5% over timescale of years Krick et al. (2015) 47 th DPS meeting 09 November 2015 SJC - 9

10 12 Fraine et al. Short-term Photometric Stability Rel. Flux Normalized Flux RMS Scatter RMS Theoretical N 1 RMS Scatter Residuals Phase Phase Difference Time per Bin (s) Bin size in seconds Fraine et al. (2013) measured transit depth of GJ1214b to precision of 40 ppm (radius to ~28 km) 14 consecutive transits coadded to produce final light curve Fig. 5. Phased & binned transit of GJ1214b at 4.5 µm fromour13spitzertransits,plusthetransitobservedbydé s e r t e t a l. ( ). Fig. 4. Standard deviation of the residuals (data minus the simultaneous fit, in units of the stellar flux) for all 14 transits at 4.5 µm, versus bin size. The red lines in the lower panel show a ±1σ envelope. Relative photometry < 100 ppm which is repeatable 47 th DPS meeting 09 November 2015 SJC - 10

11 2011 MD A Challenging Target Spitzer tracked potential AARM target 2011 MD for 19.9 hours, covering a distance of 17.5 arcmin on the sky. Shifting and adding data led to a 2.2 sigma detection (0.60+/- 0.27uJy) of asteroid at position consistent with prediction Inferred diameter is 6m [4-10 is range]; density 1.1 g/cm+3 Suggest 2011MD is a rubble-pile asteroid Asteroid was ~0.14 au from Earth at the 3me Exploited Spitzer s Earth-trailing solar orbit 47 th DPS meeting 09 November 2015 SJC - 11

12 Asteroid (2867) Steins Example 47 th DPS meeting 09 November 2015 SJC - 12

13 Create Observation SBAG 47 th DPS meeting 09 November 2015 SJC - 13

14 Visualize Observation 47 th DPS meeting 09 November 2015 SJC - 14

15 Observation Planning Overview Handled by SPOT user tool Find targets by NAIF ID or send orbital parameters to SSC Design observation Final observations are submitted with proposal Visualize observation Add a Shadow observation to measure background Constrain observation for specified date if desired or link order of observations to have multiple epochs Moving targets require special handling as they are observations that need to be fixed in time when scheduled 47 th DPS meeting 09 November 2015 SJC - 15

16 Getting Data -- Spitzer Heritage Archive Search for moving targets in the archive 47 th DPS meeting 09 November 2015 SJC - 16

17 Precovery Tool Search for moving targets in the archive Find moving targets serendipitously observed by Spitzer See Luisa s talk about IRSA 1:30pm 47 th DPS meeting 09 November 2015 SJC - 17

18 Final Thoughts Plan to operate Spitzer through hours available in Proposal deadline will be this summer Spitzer has unique capabilities for planetary science and 3.6 and 4.5 µm data are unmatched until JWST 47 th DPS meeting 09 November 2015 SJC - 18

19 Any Questions? Contact the Helpdesk at the Spitzer Science Center Visit the Spitzer Science Center web pages spitzermission/observingprograms/solarsystemprograms/ spitzer/sso_observing_with_spitzer.pdf Spitzer/IRSA demos on YouTube 47 th DPS meeting 09 November 2015 SJC - 19