Synthetic Solar System Model (S3M) MOPS Workshop Tucson, March 11th 2008 Tommy Grav

Contributors  Tommy Grav  Robert Jedicke  Steve Chesley  Matthew Holman  Tim Spahr  Larry Denneau

What is S3M?  Tool to help:  Test the MOPS pipeline  Can we detect, link and track all types of objects?  Even the special types, like interstellar comets  Can we handle the density of objects expected?  Provide efficiency determination of system  Compare PS1/PS4/LSST results to “theory”

S3M Requirements  De-biased populations  Up to date models if available  Appropriate densities  Complete to V~24.5

Where does S3M fit in? FieldDetections S3M Processing

Inner Solar System

 Near Earth Objects  Includes Inner Earth Objects  Earth Impactors  Main Belt Asteroids  Jovian Trojans  Short Period Comets

Outer Solar System

 Centaurs  Trans-Neptunian Objects  Classical Kuiper Belt  Resonant population, incl neptunian trojans  Scattered Disk Objects  Long Period Comet  Interstellar comets

What is the S3M?  ~11,000,000 objects with:  Orbital elements  Perihelion distance  Eccentricity  Inclination  Argument of perihelion  Longitude of ascending node  Time of perihelion passage  Absolute magnitude  Each population is built using its own set of assumptions and techniques

Near-Earth Objects

 Model based on Bottke et al. (2002)  Time-residence model

Earth Impactors  Made by S. Chesley  Subset of the NEOs  10M NEOs ->10006 obj  Impact from  Twice per week

Earth Impactors

Main Belt Asteroids KnownSynthetic

Main Belt Asteroids Bright Known All Known

Main Belt Asteroids  Want to retain the important features  Kirkwood gaps  Family structure  Known sample of MBAs is biased but bright portion (H < 14.5) is complete  Use bright sample to build our MBA model  Take known MBA shift (a,e,i), random angles  This “smears” out gaps and families  Hilda structure is lost

Main Belt Asteroids

Jovian Trojans

 Based on SDSS data  Integrated clone orbits  Removed non-stable  Make sure objects are 1:1 resonant

Jovian Trojans

Trojans of Other Planets  All planets   Mercury  Venus  Earth  Mars   Saturn  Uranus  Neptune  TNO model has some neptunian trojans

Centaurs

Centuars  Based on  Jedicke et al (1997)  Duncan et al (1995)  Time residence model

Trans-Neptunian Objects

 Based on Nice Model  Morbidelli & Levison  Integration of orbits  Picking clone orbits  Divide population into 3 sub-populations  Classical Kuiper belt objects  Resonant Kuiper belt objects  From the 1:1 to the 3:1 mean motion resonance  Scattered disk objects  Average a > 48AU

Trans-Neptunian Objects

Scattered Disk Objects  Average a > 48AU  Does not include Sedna-like objects

Scattered Disk Objects

Long Period Comets  Based on Franics (2005)  LINEAR data  Close to parabolic  a > 1000AU  Inclination isotropic

Interstellar comets  Eccentricity > 1  Isotropic inclination  Use no known to determine upper limit density

Grid Population  Provide the possible unknown populations  Distant circular objects  Retrograde objects  High inclination objects  Test limits of pipeline

Grid Population  Random positions and velocities  Inside a sphere of 5000AU  Eccentricities e < 1.  Absolute magnitude to ensure observability  In progress

S3M Summary KnownPS1PS4S3M Near Earth Objects~5,000 ~25,000268,896 Earth Impactors0Unknown 10,006 Main Belt Asteroids~300,000~1,000,000~10,000,00010,000,000 Jovian Trojans~2,000~20,000~100,000280,000 Centaurs~50~300~1000 Classical KBOs~1000~3000~10,00042,709 Resonant KBOs6,142 Neptunian Trojans6~50~20020,000 Scattered Disk Objects~100~500~200010,952 Jupiter Family Comets~350~500~5000TBD Long Period Comets~1000 ~94009,400 Interstellar Comets0unknown 8,300

Current Shortcomings  Somewhat MOPS specific  Easily corrected  Missing populations  Short period comets (JFCs and HFC)  Work underway by Grav & Spahr  Distant TNOs  No physical properties beyond H  Some models might need updating

Improvement Priorities  Short period comets  Un-MOPSing the models  Adding properties to calculate thermal flux  Means addition of some software to the model  Extending to fainter apparent magnitude  Adding phase integral values  Adding spectral gradient for color variations  Updating population models

Future of S3M  LSST  WISE tests of MOPS  Asteroid contamination of space missions  Other surveys (both planning/operations)