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Thermal model fjtting NEOWISE data – Straightforward Cases
Paul Pinchuk1, Nathan Myhrvold2, Jean-Luc Margot1
1UCLA Physics and Astronomy Department 2Intellectual Ventures
WISE/NEOWISE
Myhrvold N. 2018 Icarus 303 9
Thermal model fjtting NEOWISE data Straightforward Cases Paul - - PowerPoint PPT Presentation
Thermal model fjtting NEOWISE data Straightforward Cases Paul - - PowerPoint PPT Presentation
Thermal model fjtting NEOWISE data Straightforward Cases Paul Pinchuk 1 , Nathan Myhrvold 2 , Jean-Luc Margot 1 1 UCLA Physics and Astronomy Department 2 Intellectual Ventures WISE/NEOWISE Myhrvold N. 2018 Icarus 303 9 Data Filters
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Data Filters
- Photometric quality fmag = A, B, or C
- Artjfact fmag = 0; No saturated pixels
- Signal to Noise Ratjo > 4
- PSF fjt reduced <= 2
- JPL Horizons positjons within 95% CI for adjusted
sigma on RA, DEC
- Remove background object confusion cases
- Remove asteroid conjunctjons
- A minimum of 3 datapoints per band in all four bands
- Photometric
Locatjon and confusion Data reliability
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T
- tal Asteroids Remaining = 4688
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Error Scaling
- Myhrvold N. 2018 Icarus 303 9
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Error Scaling
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Thermal Models
Myhrvold N. 2018 Icarus 303 9
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Thermal Models
Myhrvold N. 2018 Icarus 303 9
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Thermal Models
- Myhrvold reparameterizatjon
- For all models - fjt by minimizing using scaled uncertaintjes
- Myhrvold N. 2018 Icarus 303 9
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Outlier Rejection
- Iteratjve procedure
- Perform model fjt with all data
- Data points with residuals greater than 3 are discarded
- Repeat procedure with remaining data points untjl convergence
- Eliminates additjonal asteroids
- Future: additjon of light curve fjttjng
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Outlier Rejection
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W3-W4 Correlation
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Comparison with NEOWISE (2011)
Masiero, J., et al., 2011. Astrophys. J. 741
- Main belt asteroids
- Systematjc ofgset:
- Mean of : 1.04
- STD of : 0.098
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Comparison with NEOWISE (PDS)
- Systematjc ofgset:
- Mean of : 1.065
- STD of : 0.142
EAR-A-COMPIL-5-NEOWISEDIAM-V1.0 NASA Planetary Data System 2
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Linear Regression Fit
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Comparison with Independent Estimates
Asteroid (km) (km) 951 12.0 N/A 14.062 0.147 951 12.2 N/A 14.062 0.147 164121 1.1 N/A 1.175 0.013 68216 1.4 N/A 1.441 0.021 Asteroid 951 12.0 N/A 14.062 0.147 951 12.2 N/A 14.062 0.147 164121 1.1 N/A 1.175 0.013 68216 1.4 N/A 1.441 0.021
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Size Distribution
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T axonomy Distribution
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Future Directions
- Light Curves
- How to handle less well-behaved cases
- Wavelength-dependent beaming parameter?
- Wavelength-dependent emissivity? (See next talk)