The Experts below are selected from a list of 1914 Experts worldwide ranked by ideXlab platform
Stefan Martin - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of the exoPlanet Detection process using four-beam nulling interferometry
2009 IEEE Aerospace conference, 2009Co-Authors: Stefan Martin, Andrew J Booth, Frank LoyaAbstract:The Planet Detection Testbed has been developed to simulate and test the Detection process for an infrared nulling interferometer observing an earthlike Planet orbiting a nearby star within about 15 pc of the solar system. The testbed combines eight beams of infrared light, four from the star and four from the Planet, simulating an ‘Xa-rray’ telescope spacecraft formation. The Detection process involves stable nulling of the starlight, rotation of the spacecraft formation, averaging over a few hours and testing of the signal against predicted exoPlanet signatures. The testbed simulates all parts of the Detection process except operation in broadband light, which is a planned upgrade for the future. This paper describes the latest results and plans for exoPlanet signal simulation, deep starlight nulling and Planet Detection at star to Planet contrast ratios of one million to one. These results are planned to demonstrate the feasibility of exoPlanet Detection using nulling interferometry at near-flightlike contrast ratios.
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exoPlanet exploration program Planet Detection test bed latest results of Planet light Detection in the presence of starlight
Proceedings of SPIE, 2008Co-Authors: Andrew J Booth, Stefan Martin, Frank LoyaAbstract:The Planet Detection Test-bed is a lab based simulation of the optics and control systems for an interferometer based Terrestrial ExoPlanet characterization mission. The test-bed supports starlight nulling at 10um infrared wavelengths, with fringe tracking at 2um wavelengths and angle and shear tracking at visible wavelengths. It further allows injection of simulated Planet light in the presence of the nulled star light, to allow testing of Planet Detection methods. We will describe the detailed construction and operation of the test-bed from an optical and control system perspective. We will also report the latest results for narrow band nulls, and the Detection of broad band Planet light in the presence of nulled starlight.
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Terrestrial Planet Finder, Planet Detection Test-Bed: Latest Results of Planet Light Detection in the Presence of Starlight
2008Co-Authors: Stefan Martin, Andrew J BoothAbstract:The Terrestrial Planet Finder, Planet Detection Test-bed is a lab based simulation of the optics and control systems for the Terrestrial Planet Finder Interferometer mission. The test-bed supports starlight nulling at 10um infrared wavelengths, with fringe tracking at 2um wavelengths and angle and shear tracking at visible wavelengths. It further allows injection of simulated Planet light in the presence of the nulled star light, to allow testing of Planet Detection methods. We will describe the detailed construction and operation of the test-bed from an optical and control system perspective. We will also report the latest results for narrow band nulls, and the Detection of broad band Planet light in the presence of nulled starlight.
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Progress in testing exo-Planet signal extraction on the TPF-I Planet Detection Testbed
Proceedings of SPIE, 2006Co-Authors: Stefan Martin, Piotr Szwaykowski, Frank Loya, Kurt LiewerAbstract:The Terrestrial Planet Finder Interferometer (TPF-I) concept is being studied at the Jet Propulsion Laboratory and the TPF-I Planet Detection Testbed has been developed to simulate the Detection process for an earthlike Planet orbiting a star within about 15 pc. The testbed combines four beams of infrared light simulating the operation of a dual chopped Bracewell interferometer observing a star and a faint Planet. This paper describes the results obtained this year including nulling of the starlight on four input beams at contrast ratios up to 250,000 to 1, and Detection of faint Planet signals at contrast ratios with the star of 2 million to 1.
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Progress in four-beam nulling: results from the terrestrial Planet finder Planet Detection testbed
2006 IEEE Aerospace Conference, 2006Co-Authors: Stefan MartinAbstract:The terrestrial Planet finder interferometer (TPF-I) is a large space telescope consisting of four 4 meter diameter telescopes flying in formation in space together with a fifth beam combiner spacecraft. The Planet Detection testbed has been developed to study the combination of the four beams of light from the telescopes in a twin nulling beam combiner which emulates the functionality of the TPF-I beam combiner. Recent results from the testbed include nulling of 4 input beams simultaneously at null depths of 250,000 to one and Planet Detection at a contrast ratio of one 2 millionth of the intensity of the star. For successful Detection of exoPlanets, the space interferometer will need to reach null depths of one million to one and demonstrate high stability during long observing periods. Testbed program goals include the same one million to one null depths and stability of the null comparable to the levels required in space (2 /spl times/ 10/sup -7/).
Frank Loya - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of the exoPlanet Detection process using four-beam nulling interferometry
2009 IEEE Aerospace conference, 2009Co-Authors: Stefan Martin, Andrew J Booth, Frank LoyaAbstract:The Planet Detection Testbed has been developed to simulate and test the Detection process for an infrared nulling interferometer observing an earthlike Planet orbiting a nearby star within about 15 pc of the solar system. The testbed combines eight beams of infrared light, four from the star and four from the Planet, simulating an ‘Xa-rray’ telescope spacecraft formation. The Detection process involves stable nulling of the starlight, rotation of the spacecraft formation, averaging over a few hours and testing of the signal against predicted exoPlanet signatures. The testbed simulates all parts of the Detection process except operation in broadband light, which is a planned upgrade for the future. This paper describes the latest results and plans for exoPlanet signal simulation, deep starlight nulling and Planet Detection at star to Planet contrast ratios of one million to one. These results are planned to demonstrate the feasibility of exoPlanet Detection using nulling interferometry at near-flightlike contrast ratios.
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exoPlanet exploration program Planet Detection test bed latest results of Planet light Detection in the presence of starlight
Proceedings of SPIE, 2008Co-Authors: Andrew J Booth, Stefan Martin, Frank LoyaAbstract:The Planet Detection Test-bed is a lab based simulation of the optics and control systems for an interferometer based Terrestrial ExoPlanet characterization mission. The test-bed supports starlight nulling at 10um infrared wavelengths, with fringe tracking at 2um wavelengths and angle and shear tracking at visible wavelengths. It further allows injection of simulated Planet light in the presence of the nulled star light, to allow testing of Planet Detection methods. We will describe the detailed construction and operation of the test-bed from an optical and control system perspective. We will also report the latest results for narrow band nulls, and the Detection of broad band Planet light in the presence of nulled starlight.
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Progress in testing exo-Planet signal extraction on the TPF-I Planet Detection Testbed
Proceedings of SPIE, 2006Co-Authors: Stefan Martin, Piotr Szwaykowski, Frank Loya, Kurt LiewerAbstract:The Terrestrial Planet Finder Interferometer (TPF-I) concept is being studied at the Jet Propulsion Laboratory and the TPF-I Planet Detection Testbed has been developed to simulate the Detection process for an earthlike Planet orbiting a star within about 15 pc. The testbed combines four beams of infrared light simulating the operation of a dual chopped Bracewell interferometer observing a star and a faint Planet. This paper describes the results obtained this year including nulling of the starlight on four input beams at contrast ratios up to 250,000 to 1, and Detection of faint Planet signals at contrast ratios with the star of 2 million to 1.
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TPF-I Planet Detection Testbed: progress in testing exo-Planet signal Detection
Proceedings of the International Astronomical Union, 2005Co-Authors: Stefan Martin, Piotr Szwaykowski, Frank LoyaAbstract:The Planet Detection Testbed is designed to simulate the architecture and operation of a space-borne four-telescope nulling interferometer. Constructed in the form of a dual chopped Bracewell interferometer together with star and Planet sources, it reproduces the principal features of the flight beam combiner designed at JPL for the proposed TPF-I Formation Flying Interferometer. The aims of the testbed are to demonstrate stable four-beam nulling and Planet Detection at representative star-Planet contrast ratios. In the flight design, starlight between 7 and 17 micron wavelength is to be nulled, and 2 to 3 micron starlight is used for fringe tracking and phasing the interferometer. There are also metrology systems and alignment systems which are required for deep and stable nulling. The testbed reproduces these features; 2 to 3 micron light from a thermal source is used for fringe tracking, and nulling and Planet Detection is performed at 10 microns. The testbed also incorporates laser metrology and other systems enabling continuous control of beam alignment. The ultimate goal is to simulate Planet Detection at star-Planet contrast ratios of order $10^{-7}$ during full rotations of the telescope array using the phase chopping method. The latest results from the testbed are presented including four-beam nulling experiments at null depths of $10^{-5}$ and Planet signal Detections at similar contrast ratios.
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Testing exo-Planet signal extraction using the Terrestrial Planet Finder Planet Detection testbed
Proceedings of SPIE, 2005Co-Authors: Stefan Martin, Piotr Szwaykowski, Frank LoyaAbstract:The Planet Detection Testbed developed at the Jet Propulsion Laboratory is being used to test direct optical Detection of an Earth-like Planet using nulling interferometry. Operating at infrared wavelengths, the testbed produces four near-identical beams simulating a distant star and Planet. The testbed is reconfigurable to simulate different telescope array designs that are being studied. Many of the systems which will be needed for the space application of nulling stellar interferometry are incorporated. The goal of the testbed is to simulate the Planet Detection process which requires both a long Detection period of many hours to overcome the thermal background noise and also high instrument stability to avoid introducing noise signals that could be mistaken for a Planet. Numerous control systems are needed to maintain the optical path differences to about 2 nm and maintain beam alignments in shear and tilt. The testbed emulates functions of the fringe-tracking and metrology systems envisioned for the flight system including finding and tracking the fringe, controlling vibration and allowing for changing conditions. The relationship of the testbed to flight conditions is discussed and the latest results are presented showing Planet Detection in the presence of bright starlight.
Christopher J Burke - One of the best experts on this subject based on the ideXlab platform.
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χ 2 discriminators for transiting Planet Detection in kepler data
Astrophysical Journal Supplement Series, 2013Co-Authors: Shawn Seader, Peter Tenenbaum, Jon M Jenkins, Christopher J BurkeAbstract:The Kepler spacecraft observes a host of target stars to detect transiting Planets. Requiring a 7.1{sigma} Detection in three years of data yields over 100,000 Detections, many of which are false alarms. After a second cut is made on a robust Detection statistic, some 50,000 or more targets still remain. These false alarms waste resources as they propagate through the remainder of the software pipeline and so a method to discriminate against them is crucial in maintaining the desired sensitivity to true events. This paper describes a {chi}{sup 2} test which represents a novel application of an existing formalism developed for false alarm mitigation in searches for gravitational waves. Using this technique, the false alarm rate can be lowered to {approx}5%.
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chi sup 2 discriminators for transiting Planet Detection in kepler data
Astrophysical Journal Supplement Series, 2013Co-Authors: Shawn Seader, Peter Tenenbaum, Jon M Jenkins, Christopher J BurkeAbstract:The Kepler spacecraft observes a host of target stars to detect transiting Planets. Requiring a 7.1{sigma} Detection in three years of data yields over 100,000 Detections, many of which are false alarms. After a second cut is made on a robust Detection statistic, some 50,000 or more targets still remain. These false alarms waste resources as they propagate through the remainder of the software pipeline and so a method to discriminate against them is crucial in maintaining the desired sensitivity to true events. This paper describes a {chi}{sup 2} test which represents a novel application of an existing formalism developed for false alarm mitigation in searches for gravitational waves. Using this technique, the false alarm rate can be lowered to {approx}5%.
Petre Stoica - One of the best experts on this subject based on the ideXlab platform.
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a combined linear programming maximum likelihood approach to radial velocity data analysis for extrasolar Planet Detection
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Prabhu Babu, Petre StoicaAbstract:In this paper we introduce a new technique for estimating the parameters of the Keplerian model commonly used in radial velocity data analysis for extrasolar Planet Detection. The unknown parameters in the Keplerian model, namely eccentricity e, orbital frequency f, periastron passage time T, longitude of periastron ω, and radial velocity amplitude K are estimated by a new approach named SPICE (a semi-parametric iterative covariance-based estimation technique). SPICE enjoys global convergence, does not require selection of any hyperparameters, and is computationally efficient (indeed computing the SPICE estimates boils down to solving a numerically efficient linear program (LP)). The parameter estimates obtained from SPICE are then refined by means of a relaxation-based maximum likelihood algorithm (RELAX) and the significance of the resultant estimates is determined by a generalized likelihood ratio test (GLRT). A real-life radial velocity data set of the star HD 9446 is analyzed and the results obtained are compared with those reported in the literature.
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ICASSP - A combined linear programming-maximum likelihood approach to radial velocity data analysis for extrasolar Planet Detection
2011 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2011Co-Authors: Prabhu Babu, Petre StoicaAbstract:In this paper we introduce a new technique for estimating the parameters of the Keplerian model commonly used in radial velocity data analysis for extrasolar Planet Detection. The unknown parameters in the Keplerian model, namely eccentricity e, orbital frequency f, periastron passage time T, longitude of periastron ω, and radial velocity amplitude K are estimated by a new approach named SPICE (a semi-parametric iterative covariance-based estimation technique). SPICE enjoys global convergence, does not require selection of any hyperparameters, and is computationally efficient (indeed computing the SPICE estimates boils down to solving a numerically efficient linear program (LP)). The parameter estimates obtained from SPICE are then refined by means of a relaxation-based maximum likelihood algorithm (RELAX) and the significance of the resultant estimates is determined by a generalized likelihood ratio test (GLRT). A real-life radial velocity data set of the star HD 9446 is analyzed and the results obtained are compared with those reported in the literature.
Ke-jia Chen - One of the best experts on this subject based on the ideXlab platform.
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SEAL - Maximum Likelihood Estimation Based on Random Subspace EDA: Application to Extrasolar Planet Detection
Lecture Notes in Computer Science, 2017Co-Authors: Ke-jia ChenAbstract:This paper addresses maximum likelihood (ML) estimation based model fitting in the context of extrasolar Planet Detection. This problem is featured by the following properties: (1) the candidate models under consideration are highly nonlinear; (2) the likelihood surface has a huge number of peaks; (3) the parameter space ranges in size from a few to dozens of dimensions. These properties make the ML search a very challenging problem, as it lacks any analytical or gradient based searching solution to explore the parameter space. A population based searching method, called estimation of distribution algorithm (EDA), is adopted to explore the model parameter space starting from a batch of random locations. EDA is featured by its ability to reveal and utilize problem structures. This property is desirable for characterizing the Detections. However, it is well recognized that EDAs can not scale well to large scale problems, as it consists of iterative random sampling and model fitting procedures, which results in the well-known dilemma curse of dimensionality. A novel mechanism to perform EDAs in interactive random subspaces spanned by correlated variables is proposed and the hope is to alleviate the curse of dimensionality for EDAs by performing the operations of sampling and model fitting in lower dimensional subspaces. The effectiveness of the proposed algorithm is verified via both benchmark numerical studies and real data analysis.
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Maximum Likelihood Estimation based on Random Subspace EDA: Application to Extrasolar Planet Detection
arXiv: Methodology, 2017Co-Authors: Ke-jia ChenAbstract:This paper addresses maximum likelihood (ML) estimation based model fitting in the context of extrasolar Planet Detection. This problem is featured by the following properties: 1) the candidate models under consideration are highly nonlinear; 2) the likelihood surface has a huge number of peaks; 3) the parameter space ranges in size from a few to dozens of dimensions. These properties make the ML search a very challenging problem, as it lacks any analytical or gradient based searching solution to explore the parameter space. A population based searching method, called estimation of distribution algorithm (EDA), is adopted to explore the model parameter space starting from a batch of random locations. EDA is featured by its ability to reveal and utilize problem structures. This property is desirable for characterizing the Detections. However, it is well recognized that EDAs can not scale well to large scale problems, as it consists of iterative random sampling and model fitting procedures, which results in the well-known dilemma curse of dimensionality. A novel mechanism to perform EDAs in interactive random subspaces spanned by correlated variables is proposed and the hope is to alleviate the curse of dimensionality for EDAs by performing the operations of sampling and model fitting in lower dimensional subspaces. The effectiveness of the proposed algorithm is verified via both benchmark numerical studies and real data analysis.