Phases of Venus and Galileo
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Planetary Phase Variations of the 55 Cancri System
The Astrophysical Journal, 740:61 (7pp), 2011 October 20 doi:10.1088/0004-637X/740/2/61 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. PLANETARY PHASE VARIATIONS OF THE 55 CANCRI SYSTEM Stephen R. Kane1, Dawn M. Gelino1, David R. Ciardi1, Diana Dragomir1,2, and Kaspar von Braun1 1 NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125, USA; [email protected] 2 Department of Physics & Astronomy, University of British Columbia, Vancouver, BC V6T1Z1, Canada Received 2011 May 6; accepted 2011 July 21; published 2011 September 29 ABSTRACT Characterization of the composition, surface properties, and atmospheric conditions of exoplanets is a rapidly progressing field as the data to study such aspects become more accessible. Bright targets, such as the multi-planet 55 Cancri system, allow an opportunity to achieve high signal-to-noise for the detection of photometric phase variations to constrain the planetary albedos. The recent discovery that innermost planet, 55 Cancri e, transits the host star introduces new prospects for studying this system. Here we calculate photometric phase curves at optical wavelengths for the system with varying assumptions for the surface and atmospheric properties of 55 Cancri e. We show that the large differences in geometric albedo allows one to distinguish between various surface models, that the scattering phase function cannot be constrained with foreseeable data, and that planet b will contribute significantly to the phase variation, depending upon the surface of planet e. We discuss detection limits and how these models may be used with future instrumentation to further characterize these planets and distinguish between various assumptions regarding surface conditions. -
On the Use of Planetary Science Data for Studying Extrasolar Planets a Science Frontier White Paper Submitted to the Astronomy & Astrophysics 2020 Decadal Survey
On the Use of Planetary Science Data for Studying Extrasolar Planets A science frontier white paper submitted to the Astronomy & Astrophysics 2020 Decadal Survey Thematic Area: Planetary Systems Principal Author Daniel J. Crichton Jet Propulsion Laboratory, California Institute of Technology [email protected] 818-354-9155 Co-Authors: J. Steve Hughes, Gael Roudier, Robert West, Jeffrey Jewell, Geoffrey Bryden, Mark Swain, T. Joseph W. Lazio (Jet Propulsion Laboratory, California Institute of Technology) There is an opportunity to advance both solar system and extrasolar planetary studies that does not require the construction of new telescopes or new missions but better use and access to inter-disciplinary data sets. This approach leverages significant investment from NASA and international space agencies in exploring this solar system and using those discoveries as “ground truth” for the study of extrasolar planets. This white paper illustrates the potential, using phase curves and atmospheric modeling as specific examples. A key advance required to realize this potential is to enable seamless discovery and access within and between planetary science and astronomical data sets. Further, seamless data discovery and access also expands the availability of science, allowing researchers and students at a variety of institutions, equipped only with Internet access and a decent computer to conduct cutting-edge research. © 2019 California Institute of Technology. Government sponsorship acknowledged. Pre-decisional - For planning -
SFSC Search Down to 4
C M Y K www.newssun.com EWS UN NHighlands County’s Hometown-S Newspaper Since 1927 Rivalry rout Deadly wreck in Polk Harris leads Lake 20-year-old woman from Lake Placid to shutout of AP Placid killed in Polk crash SPORTS, B1 PAGE A2 PAGE B14 Friday-Saturday, March 22-23, 2013 www.newssun.com Volume 94/Number 35 | 50 cents Forecast Fire destroys Partly sunny and portable at Fred pleasant High Low Wild Elementary Fire alarms “Myself, Mr. (Wally) 81 62 Cox and other administra- Complete Forecast went off at 2:40 tors were all called about PAGE A14 a.m. Wednesday 3 a.m.,” Waldron said Wednesday morning. Online By SAMANTHA GHOLAR Upon Waldron’s arrival, [email protected] the Sebring Fire SEBRING — Department along with Investigations into a fire DeSoto City Fire early Wednesday morning Department, West Sebring on the Fred Wild Volunteer Fire Department Question: Do you Elementary School cam- and Sebring Police pus are under way. Department were all on think the U.S. govern- The school’s fire alarms the scene. ment would ever News-Sun photo by KATARA SIMMONS Rhoda Ross reads to youngsters Linda Saraniti (from left), Chyanne Carroll and Camdon began going off at approx- State Fire Marshal seize money from pri- Carroll on Wednesday afternoon at the Lake Placid Public Library. Ross was reading from imately 2:40 a.m. and con- investigator Raymond vate bank accounts a children’s book she wrote and illustrated called ‘A Wildflower for all Seasons.’ tinued until about 3 a.m., Miles Davis was on the like is being consid- according to FWE scene for a large part of ered in Cyprus? Principal Laura Waldron. -
Make up Lab: Phases of Venus Introduction Galileo Is Justifiably Famous for Many Discoveries in Both Physics and Astronomy
PHYS 1401: Descriptive Astronomy Summer 2016 Make Up Lab: Phases of Venus Introduction Galileo is justifiably famous for many discoveries in both physics and astronomy. While he was fascinated by gravity and kinematics, his most valuable discovery is arguably the phases of Venus. By carefully observing and recording the progression of Venus through phases similar to our own moon, he was able to demonstrate the impossibility of the Ptolemy’s increasingly complicated geocentric model. 4. Orient yourself: Toggle on the constellation outlines and labels. Locate one or two constellations whose shapes you know. Are the constellations of 1610 recognizable to you? Face north and locate Polaris. Comment on the location of Polaris compared to its position today. Synodic Period of Venus The synodic period of an object is a measure of its motion with respect to Earth. We are most familiar with this idea as applied to the moon: to measure its synodic period, we count the time between successive full moons (or new moons, or whichever phase you like). As Galileo discovered, we can do precisely the same thing for Venus. 5. Change the date and locate Venus: Advance your date to May 01, 1610. Keep the time set to 00:00:00. Locate Venus, and zoom in to notice its phase. Advance your day until Venus Using the Stellarium program, we can replicate his is fully illuminated (100.0%) and record the date. Use the table observations by placing ourselves in the same time and place below as a model for recording your data. as Galileo himself. 6. -
194 Publications of the Measurements of The
194 PUBLICATIONS OF THE MEASUREMENTS OF THE RADIATION FROM THE PLANET MERCURY By Edison Pettit and Seth Β. Nicholson The total radiation from Mercury and its transmission through a water cell and through a microscope cover glass were measured with the thermocouple at the 60-inch reflector on June 17, 1923, and again at the 100-inch reflector on June 21st. Since the thermocouple is compensated for general diffuse radiation it is possible to measure the radiation from stars and planets in full daylight quite as well as at night (aside from the effect of seeing), and in the present instance Mercury and the comparison stars were observed near the meridian between th hours of 9 a. m. and 1 p. m. The thermocouple cell is provided with a rock salt window 2 mm thick obtained from the Smithsonian Institution through the kindness of Dr. Abbot. The transmission curves for the water cell and microscope cover glass have been carefully de- termined : those for the former may be found in Astrophysical Journal, 56, 344, 1922; those for the latter, together with the curves for rock salt, fluorite and the atmosphere for average observing conditions are given in Figure 1. We may consider the water cell to transmit in the region of 0.3/a to 1.3/x and the covér glass to transmit between 0.3μ and 5.5/1,, although some radiation is transmitted by the cover glass up to 7.5/a. The atmosphere acts as a screen transmitting prin- cipally in two regions 0.3μ, to 2,5μ and 8μ to 14μ, respectively. -
ON the INCLINATION DEPENDENCE of EXOPLANET PHASE SIGNATURES Stephen R
The Astrophysical Journal, 729:74 (6pp), 2011 March 1 doi:10.1088/0004-637X/729/1/74 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. ON THE INCLINATION DEPENDENCE OF EXOPLANET PHASE SIGNATURES Stephen R. Kane and Dawn M. Gelino NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125, USA; [email protected] Received 2011 December 2; accepted 2011 January 5; published 2011 February 10 ABSTRACT Improved photometric sensitivity from space-based telescopes has enabled the detection of phase variations for a small sample of hot Jupiters. However, exoplanets in highly eccentric orbits present unique opportunities to study the effects of drastically changing incident flux on the upper atmospheres of giant planets. Here we expand upon previous studies of phase functions for these planets at optical wavelengths by investigating the effects of orbital inclination on the flux ratio as it interacts with the other effects induced by orbital eccentricity. We determine optimal orbital inclinations for maximum flux ratios and combine these calculations with those of projected separation for application to coronagraphic observations. These are applied to several of the known exoplanets which may serve as potential targets in current and future coronagraph experiments. Key words: planetary systems – techniques: photometric 1. INTRODUCTION and inclination for a given eccentricity. We further calculate projected separations at apastron as a function of inclination The changing phases of an exoplanet as it orbits the host star and determine their correspondence with maximum flux ratio have long been considered as a means for their detection and locations. -
Absolute Magnitude and Slope Parameter G Calibration of Asteroid 25143 Itokawa
Meteoritics & Planetary Science 44, Nr 12, 1849–1852 (2009) Abstract available online at http://meteoritics.org Absolute magnitude and slope parameter G calibration of asteroid 25143 Itokawa Fabrizio BERNARDI1, 2*, Marco MICHELI1, and David J. THOLEN1 1Institute for Astronomy, University of Hawai‘i, 2680 Woodlawn Drive, Honolulu, Hawai‘i 96822, USA 2Dipartimento di Matematica, Università di Pisa, Largo Pontecorvo 5, 56127 Pisa, Italy *Corresponding author. E-mail: [email protected] (Received 12 December 2008; revision accepted 27 May 2009) Abstract–We present results from an observing campaign of 25143 Itokawa performed with the 2.2 m telescope of the University of Hawai‘i between November 2000 and September 2001. The main goal of this paper is to determine the absolute magnitude H and the slope parameter G of the phase function with high accuracy for use in determining the geometric albedo of Itokawa. We found a value of H = 19.40 and a value of G = 0.21. INTRODUCTION empirical relation between a polarization curve and the albedo. Our work will take advantage by the post-encounter The present work was performed as part of our size determination obtained by Hayabusa, allowing a more collaboration with NASA to support the space mission direct conversion of the ground-based photometric Hayabusa (MUSES-C), which in September 2005 had a information into a physically meaningful value for the albedo. rendezvous with the near-Earth asteroid 25143 Itokawa. We Another important goal of these observations was to used the 2.2 m telescope of the University of Hawai‘i at collect more data for a possible future detection of the Mauna Kea. -
NASA and Planetary Exploration
**EU5 Chap 2(263-300) 2/20/03 1:16 PM Page 263 Chapter Two NASA and Planetary Exploration by Amy Paige Snyder Prelude to NASA’s Planetary Exploration Program Four and a half billion years ago, a rotating cloud of gaseous and dusty material on the fringes of the Milky Way galaxy flattened into a disk, forming a star from the inner- most matter. Collisions among dust particles orbiting the newly-formed star, which humans call the Sun, formed kilometer-sized bodies called planetesimals which in turn aggregated to form the present-day planets.1 On the third planet from the Sun, several billions of years of evolution gave rise to a species of living beings equipped with the intel- lectual capacity to speculate about the nature of the heavens above them. Long before the era of interplanetary travel using robotic spacecraft, Greeks observing the night skies with their eyes alone noticed that five objects above failed to move with the other pinpoints of light, and thus named them planets, for “wan- derers.”2 For the next six thousand years, humans living in regions of the Mediterranean and Europe strove to make sense of the physical characteristics of the enigmatic planets.3 Building on the work of the Babylonians, Chaldeans, and Hellenistic Greeks who had developed mathematical methods to predict planetary motion, Claudius Ptolemy of Alexandria put forth a theory in the second century A.D. that the planets moved in small circles, or epicycles, around a larger circle centered on Earth.4 Only partially explaining the planets’ motions, this theory dominated until Nicolaus Copernicus of present-day Poland became dissatisfied with the inadequacies of epicycle theory in the mid-sixteenth century; a more logical explanation of the observed motions, he found, was to consider the Sun the pivot of planetary orbits.5 1. -
Morphology and Dynamics of the Venus Atmosphere at the Cloud Top Level As Observed by the Venus Monitoring Camera
Morphology and dynamics of the Venus atmosphere at the cloud top level as observed by the Venus Monitoring Camera Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr.rer.nat.) genehmigte Dissertation von Richard Moissl aus Grünstadt Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.ddb.de abrufbar. 1. Referentin oder Referent: Prof. Dr. Jürgen Blum 2. Referentin oder Referent: Dr. Horst-Uwe Keller eingereicht am: 24. April 2008 mündliche Prüfung (Disputation) am: 9. Juli 2008 ISBN 978-3-936586-86-2 Copernicus Publications, Katlenburg-Lindau Druck: Schaltungsdienst Lange, Berlin Printed in Germany Contents Summary 7 1 Introduction 9 1.1 Historical observations of Venus . .9 1.2 The atmosphere and climate of Venus . .9 1.2.1 Basic composition and structure of the Venus atmosphere . .9 1.2.2 The clouds of Venus . 11 1.2.3 Atmospheric dynamics at the cloud level . 12 1.3 Venus Express . 16 1.4 Goals and structure of the thesis . 19 2 The Venus Monitoring Camera experiment 21 2.1 Scientific objectives of the VMC in the context of this thesis . 21 2.1.1 UV Channel . 21 2.1.1.1 Morphology of the unknown UV absorber . 21 2.1.1.2 Atmospheric dynamics of the cloud tops . 21 2.1.2 The two IR channels . 22 2.1.2.1 Water vapor abundance and cloud opacity . 22 2.1.2.2 Surface and lower atmosphere . -
The H and G Magnitude System for Asteroids
Meetings The BAA Observers’ Workshops The H and G magnitude system for asteroids This article is based on a presentation given at the Observers’ Workshop held at the Open University in Milton Keynes on 2007 February 24. It can be viewed on the Asteroids & Remote Planets Section website at http://homepage.ntlworld.com/ roger.dymock/index.htm When you look at an asteroid through the eyepiece of a telescope or on a CCD image it is a rather unexciting point of light. However by analysing a number of images, information on the nature of the object can be gleaned. Frequent (say every minute or few min- Figure 2. The inclined orbit of (23) Thalia at opposition. utes) measurements of magnitude over periods of several hours can be used to generate a lightcurve. Analysis of such a lightcurve Absolute magnitude, H: the V-band magnitude of an asteroid if yields the period, shape and pole orientation of the object. it were 1 AU from the Earth and 1 AU from the Sun and fully Measurements of position (astrometry) can be used to calculate illuminated, i.e. at zero phase angle (actually a geometrically the orbit of the asteroid and thus its distance from the Earth and the impossible situation). H can be calculated from the equation Sun at the time of the observations. These distances must be known H = H(α) + 2.5log[(1−G)φ (α) + G φ (α)], where: in order for the absolute magnitude, H and the slope parameter, G 1 2 φ (α) = exp{−A (tan½ α)Bi} to be calculated (it is common for G to be given a nominal value of i i i = 1 or 2, A = 3.33, A = 1.87, B = 0.63 and B = 1.22 0.015). -
1 Revisiting 154-Day Periodicity in the Occurrence of Hard Flares. A
Revisiting 154-day periodicity in the occurrence of hard flares. A planetary influence? Ian Edmonds 12 Lentara St, Kenmore, Brisbane, Australia 4069. Ph/Fax 61 7 3378 6586, [email protected] Keywords: flare periodicity; planetary model; sunspot emergence; Mercury-Earth conjunction. Abstract. Rieger et al (1984) reported observations of a 154 day periodicity in flares during solar cycle 21. This paper discusses the observations in the light of a simple empirical planetary model of sunspot emergence. The planetary model predicts sunspot emergence when Mercury and Earth approach conjunction and Mercury approaches the Sun. We show that the reported times of flare activity are coherent with the planetary model. While the base period of the model is 170 days, the average model period, over the interval of flare recordings, is 157 days due to a 180 degree phase change in the planetary forcing near the middle of the record interval. We conclude that the periodicity at 154 days arises when the phase change in planetary forcing and the resulting progressive phase change in total sunspot area emergence and flare occurrence shifts the major peak in the flare spectrum from the planetary forcing period, 170 days, to 154 days. 1. Introduction. The observation of an ~ 154 day periodicity in the occurrence of hard flares, Rieger et al (1984), hereafter R84, initiated a now 32 year long investigation of mid-range, 40 – 2000 day, periodicities in solar activity. R84 analysed 139 flares recorded by the gamma ray spectrometer on the Solar Maximum Mission (solar cycle 21) from February 1980 through to the end of 1983 when recording ceased. -
Phase Integral of Asteroids Vasilij G
A&A 626, A87 (2019) Astronomy https://doi.org/10.1051/0004-6361/201935588 & © ESO 2019 Astrophysics Phase integral of asteroids Vasilij G. Shevchenko1,2, Irina N. Belskaya2, Olga I. Mikhalchenko1,2, Karri Muinonen3,4, Antti Penttilä3, Maria Gritsevich3,5, Yuriy G. Shkuratov2, Ivan G. Slyusarev1,2, and Gorden Videen6 1 Department of Astronomy and Space Informatics, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv 61022, Ukraine e-mail: [email protected] 2 Institute of Astronomy, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv 61022, Ukraine 3 Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2, 00560 Helsinki, Finland 4 Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, 02430 Masala, Finland 5 Institute of Physics and Technology, Ural Federal University, Mira str. 19, 620002 Ekaterinburg, Russia 6 Space Science Institute, 4750 Walnut St. Suite 205, Boulder CO 80301, USA Received 31 March 2019 / Accepted 20 May 2019 ABSTRACT The values of the phase integral q were determined for asteroids using a numerical integration of the brightness phase functions over a wide phase-angle range and the relations between q and the G parameter of the HG function and q and the G1, G2 parameters of the HG1G2 function. The phase-integral values for asteroids of different geometric albedo range from 0.34 to 0.54 with an average value of 0.44. These values can be used for the determination of the Bond albedo of asteroids. Estimates for the phase-integral values using the G1 and G2 parameters are in very good agreement with the available observational data.