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SPHEREx AllSky Survey Small Body Science

0.8 – 5.0 um, 96 Bands 0.045µm wide

2 Year ConMnuous All-Sky Survey

C.M. Lisse & the SPHEREx Science Team Johns Hopkins University Applied Physics Laboratory SBAG 16, 12 January 2017 SPHEREx = 2016/2017 Proposed MIDEX Class Astrophysics Mission

• PI Jaime Bock, Caltech • No Moving Parts, Single Observing Mode • Large Technical & Scien@fic Margins. • synchronous orbit, 2 year baseline mission covering whole sky 4x. • Follows successful CaITech/JPL mgt. model of NuSTAR • Simple and robust design that maximizes spectral throughput and efficiency. • 20 cm all-aluminum telescope with a wide 3.5° x 7° field of view, imaged onto four 2k x 2k HgCdTe detector arrays. These H2RG arrays have been qualified for space observa@ons by JWST. • Four space-demonstrated linear varable filters (LVFs) to produce spectra. This method was demonstrated by LEISA on to obtain excellent spectral images of and . • Radia@vely cooled telescope to ≤ 80K with 2 detectors that are cooled to ≤ 55K with 320% total margin on the net heat load. The thermal methods employed on SPHEREx have been previously demonstrated by Planck, Spitzer, and WISE.

SPHEREx Payload Design

SPHEREx Sun- Synchronous Sky Viewing Geometry (COBE, WISE) SPHEREx LimiMng SensiMviMes ~ Same As WISE’s (H, K ≥ 18 mag), But in 96 Spectral Bands, Not Two

SPHEREx (1/2016) WISE , , Centaur DetecMons

• ~200,000 • ~200 • ~30 Centaurs • No KBOs (??!) Pluto [V] ~ 15, [K] ~ 13, should have been detectable. Was near galac@c center, so maybe confused? • There are 15 large KBOs within 5 mags’ brightness of Pluto: , , , Orcus, Quaoar, Ixion, 2007 JJ43, 2002 TX300, 2002 AW197, 2002 UX25, Varuna, 2002 MS4, 2010 EK139, 2003 AZ84 Key SPHEREx Solar System Projects

• Spectral Survey of Thousands of Asteroids – beqer reckoning of the origin and dynamical evolu@on of their types based on their reflectance spectra & sizes/albedos from their thermal emission. Were they formed in layered zones of the PPD then scahered? • Spectral classifica@on of 100’s of asteroids – compare to Outer Main Belt. Were they formed with Jupiter, captured from the Outer Main Belt, or delivered in the LHB? • Spectral determinaMon of Cometary chemical abundances, as tracers of the PPD’s composi@on. E.g KB comets vs Comets & CO2in Comets dominates C-ices – the Fundamental Carbon Bearing Molecule in the PPD? And by extension in all molecular clouds and hot cores? • Spectral Mapping of the Zodiacal Cloud in Time and Space. What sources this cloud, asteroids, comets, KBOs? • RotaMonally resolved spectra of the largest KBOs. E.g. do other KBOs show the CO/ CH4 peaks of Pluto’s lightcurve [K ~ 13], coordinated with the ice-rich Sputnik Plenum glacier? + • Monitor Planetary Weather: CH4, H2O clouds; Hazes; Giant H3 aurorae and obtain RotaMonally Resolved Planetary Lightcurves as Templates for Extra-solar Planet Behavior

• "Follow the Water" and Other Key Species (CO, CO2, Organics [CH4, C2H6, HCN, CH3OH, H2CO, PAHs], NH3 ) throughout the Solar System, as Cri@cal Resource for . hhp://spherex.caltech.edu/Workshop.html KBO Science: What are These Bodies Made of, And Does This Vary Across the ? We Know Densi@es Vary from 0.5 g/cm3 up to 2.5 g/cm3. Many Evince Strong Organic Ices Lines, Others Mainly Water. Why? Size? Evolu@on? How Do Binary KBO Partners Compare Spectrally? Pluto

KBO NIR Spectroscopy The Heart SPHEREx Should be Able to Classify 10’s of KBOs and 1,000’s of Centaurs (Grav et al. 2011)

N.B. : [K]Pluto = 13.3 Comet Science: Primi@ve Ice Reservoirs Formed in the Solar Nebula, at the Edge of the PPD, or in its midplane? 50 Comets, Saturnian Icy Abundances vs. Water

Grey is range of N2 observed comet abundance

Orange is where Cassini’s MS has measured Enceladus’ abundances AKARI

CO2,CO in 18 Comets PAHs in Comets as in Hot Cores and Dense Clouds?

Deep Impact Spitzer/IRS Pah Lines

Found in CI Meteroites

3.29 um NIR PAH Feature for SPHEREx Interestellar Comets? SPHEREx Should be Able to Survey & Compare 100’s of Comets in an Unbiased Sample Science : Were the Trojans Formed in Place, or Accreted During the LHB?

Ceres Moon

Mercury

Mars

Wherever we look in the Solar System, we see massive cratering. Trojan Asteroid NIR Spectroscopy SPHEREx Should be Able to Classify 1,000’s of Trojan Asteroids in an Unbiased Sample Asteroid Science : Were Asteroids Formed From a Chemically Segregated Solar PPD and Then Mixed?

Sample Size ~ 250 Substructure ProbelmaMc

Silicate Rich Carbon Rich Asteroids NIR CharacterizaMon ConMnuum shape = composiMon; Albedo + thermal emission = Size Example 1, , 1/3 of the Main Belt’s Mass: Formed at ~2.5 AU With Abundant H2O & NH3 or in the Outer Solar System & Captured? Important Mineralogical Signature in SPHEREx Passband SPHEREx will survey & classify 10,000’s of Asteroids in an unbiased sample.

(In fact, asteroids will have to be removed from the SPHEREx all sky survey in order to produce clean astrophysical detecMons.) And Last But Not Least: Zodiacal Dust Cloud Structure & ComposiMon

• SPHEREx will be geyng measurement of diffuse Zody foreground with every sample • Maps of I(elonga@on, @me, wavelength) • Can search for trails, enhancements near , varia@on through Main Belt • Test of 10% bright asteroidal + 90% dark cometary dust hypothesis