Solar System Theory and Observa3ons Stefanie Milam JWST Deputy Project Scientist for Planetary Science NASA Goddard Space Flight Center Z=0 No Z Z- NON ATLAS Workshop: Massively Parallel Large Area Spectroscopy from Space
Solar System Science with Astrophysics Missions HST News Circulation - Calendar 2013 (Source: Meltwater News) 600 500 400 400 Circulation in millions 2.3% 15.4% 300 300 200 200 100 100 0 Fomalhaut planet orbit brown dwarf atm. Heritage M106 galaxy strobing protostarstar MW halo stars' motion Heritage: space invader oldest nearby star LMC X-ray source farthest supernova Horsehead nebula/anniversary comet ISON Hyades WD planet debris Ring nebula structure Proxima Cen. planned obs. T-Pyx nova TW Hydrae planetary gap Heritage Arp 142 comet ISON movie blue exoplanet Neptune moon Heritage: comet ISON GRB Kilonova Magellanic stream origin Galaxies in time M87 black hole jet movie Heritage "caterpillar" nebula ESA - planetary neb. Alignment Huge Globular Cluster population Water laden asteroids comet ISON Heritage Farthest galaxy (UTX co-release) Frontier Fields active asteroid Milky Wat evolution water on exoplanets Europa Plumes 7-Jan8-Jan5-Feb 7-Feb 21-Feb 5-Mar 7-Mar 4-Apr 4-Apr 19-Apr 23-Apr 9-May 23-May 3-Jun4-Jun 13-Jun 20-Jun 2-Jul 11-Jul 15-Jul 25-Jul 3-Aug 8-Aug 15-Aug 22-Aug 29-Aug 2-Sep 12-Sep 10-Oct 17-Oct 23-Oct 24-Oct 7-Nov 14-Nov 2-Dec 12-Dec
ATLAS and the Solar System ATLAS Science Objec-ve 4, "Probe the forma-on history of the outer Solar System through the composi-on of 3,000 comets and asteroids," flows down to a Solar System Survey with 3000 individual poin-ngs, covering a total area of 1,200 sq deg. ATLAS can provide valuable insight into the proper-es and composi-on of Solar System objects from comets and asteroids to Trans- Neptunian objects. ATLAS Solar System Survey will focus on the likle explored Kuiper Belt Objects.
Small Bodies in the Solar System
The Outer Solar System Kuiper Belt Objects (KBOs) Trans- Neptunian Objects (TNOs) T ~ 50 K à NIR will not probe thermal emission. Determining albedo and diameter will need other facili-es
The KBO popula3on as we know it D<500 km KBOs which dominate the mass of the popula-on Only features iden-fied in the IR spectra of small KBOs are absorp-on features: ü water- ice (1.5μm and 2.0μm) ü methane ü methanol Not able to iden-fy the silicate components in KBOs even from New Horizons Lack of iden-fying absorp-on features in the λ~2.5micron, the current wavelength limit beyond which telescopes lack sufficient sensi-vity to gather quality spectra for the majority of KBOs [ALL SMALL BODIES]. Wang et al. 2018 and references therein
Pluto from New Horizons Flyby
Pluto from VLT Protoppa et al. 2008
TNOs in the Era of JWST Obtain full NIR spectra of larger TNOs and characterize them. Photometry (NIRCam) of smaller objects. Composi-onal studies of every known target 100 km in a reasonable amount of observing -me. Simulated Centaur (D~80km at 22AU) JWST NIRSpec R~1000 Parker et al. 2016
WFIRST Surveys and small body detec-ons KBO detec3ons in WFIRST surveys WFIRST will reach r~27 (diameter of ~20 km)** with each set of exposures in a par-cular filter during the HLS survey (KNOWN KBOs) ~2.5 mag fainter (10 -mes lower flux) than the DES and LSST surveys Serendipitous discovery of NEW KBOs is dependent on cadence detec-on is possible at ~1 day increments. Observa-ons with mul-ple filters will result in near- infrared spectral slopes that provide a first- order HLS look at composi-onal differences. detec-on of new minor bodies with the HLS could probe an interes-ng subset of the color phase space of the <150 km objects SNe Holler et al. 2018 **Assuming a heliocentric distance of 40 AU, an observer distance of 39 AU, a geometric albedo of 0.08, an average g- r color for KBOs of 0.65, and using the SDSS to Johnson filter conversions from R. Lupton*
Where are they? KBOs have a complex and finely structured popula-on distribu-on, with the majority of the popula-on in low- inclina-on, low- eccentricity orbits Ø near the eclip-c Ø density of KBOs decreases rapidly further from the eclip-c. However, there are excep-ons ʻOumuamua
ATLAS Solar System Survey and ATLAS Wide Pointed survey of ~3000 KBOs (iden-fied from previous surveys) 2500s integra-ons for SNR~10 sensi-vity of OH feature at 3 microns No tracking required Rates ~1-4 /hr Sequence slits as targets move 1000s integra-ons? ATLAS Wide will detect >250 targets Wang et al. 2018
Asteroids the other small bodies Surveys to serendipitously detect asteroids will depend on loca-on most are VERY close to the Eclip-c. However access to the NIR that is not accessible from the ground is interes-ng see Rivkin et al. 2016. 2.5-2.8 micron would be useful for all targets Ceres Spectrum from IRTF R~200 <2micron, R~3000 >2.3 micron Ceres from IRTF Holler et al. 2018 From Rivkin, personal communica-on
Characterizing Asteroids with ATLAS Challenging, but do- able for brighter targets Will take ~2 min for average asteroid to cross slit Can bin to lower resolu-on to enhance sensi-vity The 2.5-2.8 micron range is s-ll appealing even for bright targets Will complement WFIRST and ground- based surveys (e.g. LSST)
Moving Targets MOVE Milam et al. 2016
MT Tracking As a spectroscopic mission, the implica-ons for MT tracking are significant. Access to more of the Solar System Dynamic Objects that always need observa-ons New Science enabled!!! Coupled with dynamic range. Blurring of the flux contained within one WFIRST WFI pixel (0.11 / pixel) in one detector readout -me (2.7 seconds) for the cases of no moving target tracking and moving target tracking of up to 30 mas/s. Holler et al. 2018
Other Solar System Science? Satellite characteriza-on and monitoring Plumes, volcanos, weather (Titan) Planetary atmospheres (???) Weather, seasonal varia-on, impact events Rings Composi-on, new rings Comets Composi-on of new objects (comae, tails, etc) E.g., see PASP special issue on Solar System Science with JWST.
Summary Solar System science enabled by space telescopes is compelling to not only the science community, but also the public. Spectroscopic survey capability will reveal new insights into the composi-on of small bodies and help constrain theories of solar system forma-on/evolu-on. MT tracking enables addi-onal science for the solar system. ATLAS will be a significant complementary resource to current/ future survey assets.
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