Download or read book The Implementation of Stellar Occultation Light Curve Modelling for Arbitrary Planetary Atmospheric Structures and the Analysis of Pluto s Occultation Light Curves and Its Atmosphere written by Chanita Tubthong and published by . This book was released on 2021 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: For decades, the analyses of stellar occultation light curves have been the most efficient method to study atmosphere of small solar system bodies. The variation in stellar flux due to the refraction in planetary atmosphere is directly related to the temperature profile of the planetary atmosphere. In this thesis, we implemented the occultation model derived by Chamberlain and Elliot (1997) [2], which is compatible with any occulting body with arbitrary temperature profile. The implementation was used to analysed Pluto occultation light curve of the star P384.2 on June 12, 2006. The result from the fit suggested that, if Pluto's temperature profile in June 2006 were isothermal, it profile would be consistent with the surface temperature of 74.2 ± 1.4 K. The best fit light curve from the isothermal model, however, expressed some inconsistency near the closest approach. The result, therefore, suggested that neither isothermal model nor the model with temperature gradient are sufficient to describe Pluto's temperature profile. More complicated temperature profiles should be considered, which are enable with this implementation.
Download or read book A Numerical Method for Calculating Occultation Light Curves from an Arbitrary Atmospheric Model written by Dawn Marie Chamberlain and published by . This book was released on 1996 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Use of Stellar Occultations to Study the Figures and Atmospheres of Small Bodies in the Outer Solar System written by Michael James Person and published by . This book was released on 2006 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The methods of analyzing stellar occultations by small bodies in the outer solar system are discussed with examples from Triton, Pluto, and Charon. Simulations were performed characterizing the analysis of multi-chord occultations including: the effects of the direction of residual minimization in figure fits, the complications in measuring the reliability of fitted figure parameters when there are few degrees of freedom, and the proper treatment of grazing chords in model fitting. The 2005 July 11 C313.2 stellar occultation by Charon was analyzed. Occultation timings from the three published data sets were combined to accurately determine the mean radius of Charon: 606.0 ± 1.5 km. The analysis indicates that a slight oblateness in the body (0.006 ± 0.003) best matches the data, with a confidence level of 86%. Charon's mean radius corresponds to a bulk density of 1.63 0.07 g/cm3, which is significantly less than Pluto's (1.92 ± 0.12 g/cm3), consistent with an impact formation scenario in which at least one of the impactors was differentiated. The 2002 August 21 P131.1 and the 1988 June 9 P8 stellar occultations by Pluto were analyzed.
Download or read book An Analysis of Occultations and Phase Curves of Kepler Planetary Candidates written by Jessica E. Roberts and published by . This book was released on 2014 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present initial results from our occultation and phase curve catalog of Kepler planets and planetary candidates. We applied a new numerical occultation model for each light curve in our catalog. From this analysis, we demonstrated the importance of investigating occultations and phase curves in order to find false positives in the KOI data set. We calculated the brightness temperatures of KOI 418.01 and KOI 960.01. These temperatures allowed us to conclude both are false positives. Using the phase curve amplitudes, we were able to estimate masses of 0.169 M[subscript] {u2609} and 1.43M[subscript] {u2609}, respectively, and eccentricities of 0.668 and 0.732, respectively. We concluded that both objects are eclipsing binaries. We also discussed the occultations of two confirmed super-Earths, Kepler 10b and Kepler 407b. Assuming all planetary flux is due to reflected light, we found that both planets have geometric albedos >0.4. An alternative explanation is presented in which we concluded that the planetary flux observed is due to both backscattering reflected light as well as a thermal component.
Download or read book Spacecraft and Stellar Occultations by Turbulent Planetary Atmospheres written by Bjarne S. Haugstad and published by . This book was released on 1981 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long propagation paths involved in radio and stellar occultations by turbulent planetary atmospheres require that the classical, weak scattering scintillation theory be expanded to account for the inhomogeneous ambient atmosphere upon which the turbulence is superimposed. Such coupling between the turbulent and the ambient components of refractivity reduces the scintillation index by less than a factor of two in shallow radio occultations. For stellar occultations the reduction varies between this value for very small projected stellar radii, to approximately a factor of 3.6 when the projected stellar radius above the planetary limb greatly exceeds the radius of the free-space Fresnel zone at this distance. More profound changes are found in the scintillation power spectrum, the shape of which depends strongly on both occultation depth and geometry when coupling to the inhomogeneous background is properly accounted for. Second-order, systematic propagation effects calculated from both geometrical optics and a wave-optical formulation show that the average phase velocity is increased in the presence of turbulence. The finite wavelength dependence of the phase path bias implies that an initially non-dispersive medium becomes slightly dispersive by the addition of turbulence. Atmospheric profiles derived from occultations by turbulent planetary atmospheres differ only slightly from those of the corresponding non-turbulent atmosphere when the weak scattering condition is satisfied.
Download or read book The Geometry of Stellar Occultation Measurements on Long Duration Atmospheric Monitoring Missions written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-06 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geometrical considerations are presented for analyzing use of the stellar occultation technique on long duration earth atmosphere monitoring missions. The simulated mission data are presented for three representative orbits. Bright near infrared stars are used as examples of how extensive global longitude-latitude coverage is obtained by performing occultation measurements on several stars during the course of a one year mission. A comparison is made with similar missions using the sun as a light source. Brooks, D. R. Langley Research Center NASA-TM-80138 RTOP 146-20-14-01
Download or read book A Practical Guide to Lightcurve Photometry and Analysis written by Brian D. Warner and published by Springer. This book was released on 2016-06-20 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tools for amateur astronomers who wish to go beyond CCD imaging and step into ‘serious’ science. The text offers techniques for gathering, analyzing, and publishing data, and describes joint projects in which amateurs and students can take part. Readers learn to recognize and avoid common errors in gathering photometry data, with detailed examples for analysis. Includes reviews of available software, with screen shots and useful tips.
Download or read book Shape Modeling Attitude Estimation and Classification of Artificial Resident Space Objects RSO Using Photometric Light Curves written by Katiyayni Balachandran and published by . This book was released on 2022 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light curve inversion (LCI) has proven valuable in using photometric measurements to optimize various physical parameters of a resident space object (RSO) such as rotational period about its own spin axis, pole orientation and others. Other characteristics such as shape and size are dependent on the surface brightness. To accurately determine size, shape, spin rate, or attitude information of an unresolved resident space object, photometry is required to capture the relatively rapid changes in brightness that these objects can exhibit. LCI has been developed significantly for asteroids, although not fool-proof for artificial RSOs. Satellites and space debris, unlike asteroids, are dynamic in lighting and viewing geometry because they are closer to Earth. Additionally, while asteroids are roughly round, smooth, and have stable rotations, the opposite is true of man-made space objects, which often have sharp edges and flat surfaces that produce distinct specular glints. The minimal studies performed for satellites utilize a priori information on attitude and a simplified geometric model such as a cuboid. The objective is to determine the sidereal rotation period and shape of the RSO and subsequently, classify the object using these parameters. Optical measurements for space object tracking are sensitive to shape, attitude,angular velocity, and surface parameters. Current state-of-the-art in RSO characterization relies heavily on nonlinear estimation theory which is computationally expensive.A data-driven approach for improved accuracy with a large volume of objects employs the use of deep neural networks. Given an unresolved object's light curve, in low earth orbit (LEO), we can characterize it by shape and spin rate using a Hidden Markov model (HMM) and Long Short-term Memory Recurrent neural network (LSTM RNN). The tumbling rates are computed using the Lomb-scargle periodogram, which performs more accurately as opposed to other signal processing methods, and the synthetic light curves are generated using the Lebedev quadrature. This integrated model has been developed to identify tumbling and stabilized objects by testing for aliasing, periodicity, and feature extraction.The application of photometric light curves has been extended to model Triton's atmosphere. To quantify the distortion required to reproduce the measured light curve (stellar occultation), a global model of the atmosphere of varying ellipticity can be constructed and fit using least-squares method. We can use the operations concept of a space probe releasing hundreds of small satellites into orbit around Triton in delayed succession to improve data collection capability and provide redundancy due to power constraints. The simulated data (with additional astrometric data of Triton)can be 3D mapped to generate the atmospheric model and validate predictions of Triton's expanding atmosphere due to thermal properties of the surface and increase in pressure.
Download or read book Occultations for Probing Atmosphere and Climate written by Gottfried Kirchengast and published by Springer. This book was released on 2010-11-30 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Use of occultation methodology for observing the Earth's atmosphere and climate has become so broad as to comprise solar, lunar, stellar, navigation and satellite crosslink occultation methods. The atmospheric parameters obtained extend from the fundamental variables temperature, density, pressure, water vapor, and ozone via a multitude of trace gas species to particulate species such as aerosols and cloud liquid water. Ionospheric electron density is sensed as well. The methods all share the key properties of self-calibration, high accuracy and vertical resolution, global coverage, and (if using radio signals) all-weather capability. Occultation data are thus of high value in a wide range of fields including climate monitoring and research, atmospheric physics and chemistry, operational meteorology, and other fields such as space weather and planetary science. This wide area of variants and uses of the occultation method has led to a diversi fication of the occultation-related scientific community into a range of different sub-communities, however. The 1st International Workshop on Occultations for Probing Atmosphere and Cli mate-OPAC-1- held September 16-20, 2002, in Graz, Austria, has set in ex actly at this point. OPAC-1 aimed at providing a casual forum and stimulating at mosphere fertilizing scientific discourse, co-operation initiatives, and mutual learning and support amongst members of all the different sub-communities. The workshop was attended by about 80 participants from 17 different countries who actively contributed to a scientific programme of high quality and to an excellent workshop atmosphere, which was judged by the participants to have fully met the aims expressed.
Download or read book From Interacting Binaries to Exoplanets IAU S282 written by Mercedes T. Richards and published by Cambridge University Press. This book was released on 2012-05-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In IAU Symposium 282, members of the exoplanet and binary star communities unite for the first time to discuss the state-of-the-art discovery, imaging, modeling and analysis tools used to study stars, brown dwarfs and exoplanets in multiple-object systems. They describe detection techniques using advanced telescopes and detectors, including the Kepler mission and the proposed Gaia and LSST projects. Imaging techniques discussed include adaptive optics, interferometry, polarimetry and tomography, while key modeling tools are covered in detail. Other topics include simulations of formation mechanisms in binary star systems, non-conservative evolution of binary stars, the formation and evolution of planets and a theory for the structure, atmospheres and evolution of giant exoplanets. The volume concludes with hydrodynamic simulations, models of planetary atmospheres and the habitability of exoplanets. These proceedings demonstrate how sophisticated modeling codes bridge the gap between theory and observations and increase our understanding of binary and multiple systems.
Download or read book Stellar Occultation Studies of Saturn s Upper Atmosphere written by Jeffrey Alan Foust and published by . This book was released on 1999 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Evolution on Inhabited and Lifeless Worlds written by David C. Catling and published by Cambridge University Press. This book was released on 2017-04-13 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative text on the formation and evolution of planetary atmospheres, for graduate-level students and researchers.
Download or read book Occultation Studies of Planets and Satellites written by Edward Willson Dunham and published by . This book was released on 1978 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Solar System Beyond Neptune written by M. Antonietta Barucci and published by University of Arizona Press. This book was released on 2008 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new frontier in our solar system opened with the discovery of the Kuiper Belt and the extensive population of icy bodies orbiting beyond Neptune. Today the study of all of these bodies, collectively referred to as trans-Neptunian objects, reveals them to be frozen time capsules from the earliest epochs of solar system formation. This new volume in the Space Science Series, with one hundred contributing authors, offers the most detailed and up-to-date picture of our solar systemÕs farthest frontier. Our understanding of trans-Neptunian objects is rapidly evolving and currently constitutes one of the most active research fields in planetary sciences. The Solar System Beyond Neptune brings the reader to the forefront of our current understanding and points the way to further advancement in the field, making it an indispensable resource for researchers and students in planetary science.
Download or read book Atmosphere and Climate written by Ulrich Foelsche and published by Springer Science & Business Media. This book was released on 2006-05-24 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents carefully edited and peer-reviewed papers from the 2nd International Workshop on Occultations for Probing Atmosphere and Climate (OPAC-2), held in Graz, Austria. It starts with a general introductory paper and proceeds to address the full range from methodology in general via specific occultation methods (GNSS-LEO, LEO-LEO, stellar and solar) to the use of occultation data, with focus on atmospheric physics, meteorology and climate.
Download or read book Spectroscopy and Photochemistry of Planetary Atmospheres and Ionospheres written by Vladimir A. Krasnopolsky and published by Cambridge University Press. This book was released on 2019-02-14 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the fundamentals for studying chemical compositions of planetary atmospheres and ionospheres, for graduate students and researchers.
Download or read book The Non sphericity of Triton s Atmosphere as Evidenced by Stellar Occultations written by Michael James Person and published by . This book was released on 2001 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
