Our new paper titled “Amplitude and phase retrieval with simultaneous diversity estimation using expectation maximization” has been published in OSA JOSA A. The paper can be accessed through DOI.
231st AAS Meeting
A couple of us from SIOSLab attended the 231st AAS Meeting which took place in Washington, D.C. earlier this month. Daniel Garrett presented his poster titled “Building Better Planet Populations with EXOSIMS.” Dean Keithly presented his poster titled “Exoplanet Target Selection and Scheduling with Greedy Optimization.” Gabriel Soto presented his poster titled “Starshade Observation Scheduling for WFIRST.”
Direct Imaging Post-Processing Research Update
We have been working on using Common Spatial Pattern filtering in a novel method to detect exoplanets from direct imaging. Using just time-series data, CSP filtering can identify a known exoplanet, Beta Pictorus b (in image below). Right now, work is being done to implement spectral characteristics from the observations into the data reduction process as well. Similarly, we are preparing to run large-scale statistical analysis across hundreds of observations. This will serve to compare to the current method, Principal Component Analysis. Hopefully we can identify situations in which CSP outperforms PCA in planetary detection.
New Starshade Additions to EXOSIMS
I have been working recently on the integration of a new starshade class into EXOSIMS which can simulate starshade motion with higher fidelity. The humbly named SotoStarshade class integrates the circular restricted three body equations of motion to find the states of the occulter as it dances around a telescope on an L2 halo orbit in a rotating frame. As of now, it can solve boundary value problems to determine slew trajectories: while the telescope slews to a new target the occulter flies over to align with the telescope’s line of sight. This slew time can be varied accordingly to reduce the amount of fuel used in the impulsive maneuvers or can even be minimized given fuel constraints. With this new starshade class, trajectories can be generated throughout the mission.
The video shown above shows the simulation of the starshade motion about L2 as the telescope slews to view new targets. Slew times are set to 20 days for every target and the station-keeping motion is not shown. New methods will be introduced in the near future that can interpolate the fuel costs for quick calculations and vary the slew times to sync with targets coming in and out of the Sun (and other planetary) keepout zones in the sky; a new scheduler will also be added to the SurveySimulation module.
SPIE Optics + Photonics 2017
Quite a few of us attended the SPIE Optics + Photonics conference on 6-11 August 2017 in sunny San Diego, CA. Daniel Garrett presented his paper “Detected exoplanet population distributions found analytically.” Dmitry Savransky presented his paper “Multi-mission modeling for space-based exoplanet imagers.” Jacob Shapiro presented his paper “Planet signal extraction from direct imaging using common spatial pattern filtering.” Gabriel Soto presented his papers “Starshade orbital maneuver study for WFIRST” and “Optimization of high-inclination orbits using planetary flybys for a zodiacal light-imaging mission.”
AJ Paper Published
Our new paper, “A Simple Depth-of-Search Metric for Exoplanet Imaging Surveys,” has been published in The Astronomical Journal. Access the paper here.
Congratulations to Daniel Garrett on Passing his A Exam!
Daniel Garrett successfully passed his A exam on May 24th, marking his entrance into the dissertation phase of his degree program.
A 30 Second History of Exoplanet Exploration
I recently updated a video I’ve been showing for the last few years in public talks on exoplanets. This shows the current population of known exoplanets, in order of discovery and coded by discovery method.
The code to generate this video is available at: https://github.com/dsavransky/miscpy/blob/master/Animaitons/exoplanet_history_anim.py
Data is from the NASA Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu/).
SGRS at Cornell, January 20th 2017
SIOSLab attended the 2017 Sibley Graduate Research Symposium (SGRS) held in Upson Hall at Cornell University on January 20th, 2017. Joyce Fang presented her talk titled “Misalignment Retrieval of an Off-axis Parabolic Mirror using Kalman Filtering.” Jacob Shapiro presented his talk titled “Improved Signal Detection in Direct Imaging of Exoplanets.” Gabriel Soto presented his talk titled “Starshade Orbital Maneuver Study for WFIRST.”
229th AAS Meeting
SIOSLab attended the 229th AAS Meeting in Grapevine, Texas earlier this month. Daniel Garrett presented his poster titled “Analytical Methods for Exoplanet Imaging Detection Metrics.” Jacob Shapiro and Nikhil Ranganathan presented their poster titled “Blind Source Separation Algorithms for PSF Subtraction from Direct Imaging.” Gabriel Soto presented his poster titled “Starshade Orbital Maneuver Study for WFIRST.”
