DOCSLIB.ORG

Gaia and the Asteroid Population: a Revolution on Earth, Coming from Space

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gaia and the Asteroid Population: a Revolution on Earth, Coming from Space P. Tanga GREAT - EWASS Athens 2016 March 16, 2017 GAIA AND THE ASTEROID POPULATION: A REVOLUTION ON EARTH, COMING FROM SPACE P. Tanga Laboratoire Lagrange, Observatoire de la Côte d’Azur, France P. Tanga – Gaia and the Solar System 2 Gaia ID card • It is a ESA cornerstone scientific mission: • 5 years of observations – ESA: building, operation (nominal mission started in July 2014) – Scientific community: data reduction • Positioned around L2 – No instrument PI, no proprietary period • automated selection of sources , on • Astrometry: input catalog – 109 stars, V<20 • Self-monitored, onboard metrology – 25 µas at V~15 • Heritage of Hipparcos – uniform sky coverage (70-100 obs./ source) • Physical observations: • Spectro-photometry • Radial velocities, hi-res spectra (V<16.5) 3 webinar P. Tanga – Gaia and the Solar System 3 Gaia in the history of astrometry 5 webinar P. Tanga – Gaia and the Solar System 4 ESA/Gaia/DPAC/Airbus DS webinar Optics Two SiC primary mirrors 1.45 × 0.50 m2, F = 35 m Rotation axis (6 h) 106°.5 Combined focal plane (CCDs) M4: beam SiC toroidal combiner Figure courtesy EADS-Astrium structure webinar P. Tanga – Gaia and the Solar System 6 ESA/Gaia/DPAC/Airbus DS webinar Sunshield deployment test – Oct. 2011 P. Tanga – Gaia and the Solar System 8 December 19, 2013 webinar P. Tanga – Gaia and the Solar System 9 The scanning law Rotation axis movement Scan path in 4 days Scan path 4 days 4 rotations/day Spin axis Spin axis trajectory 4 days 45° Sun trajectory, 4 months Sun Spin axis trajectory, 4 months webinar P. Tanga – Gaia and the Solar System 10 Focal plane 1 pixel 60 x 180 mas 106 CCDs (4.5 x 2 kpix) = 1 Gpixel SM1-2 AF1 - 9 BP RP RVS 420 mm 0.69° WFS WFS BAM BAM sec FOV1 0s 10.6 15.5 30.1 49.5 56.3 64.1 sec FOV2 courtesy F. Mignard, OCA 0s 5.8 10.7 25.3 44.7 51.5 59.3 webinar P. Tanga – Gaia and the Solar System 11 The Astrometric Global Iterative Solution (AGIS) • Simultaneous all-sky solution of positions, parallaxes, proper motions, physical parameters (e.g. color) and instrument calibration parameters • Link to ICRS by VLBI sources directly observed by Gaia —> All aspects of the data reduction are deeply connected webinar P. Tanga – Gaia and the Solar System 12 Gaia as Micro-meteorite detector Corrective torques applied to recover spacecraft attitude after a meteoroid strike (Perseid activity peak). webinar P. Tanga – Gaia and the Solar System 13 The strengths of Gaia • Astrometry: • Accurately measure relative positions at large angles —> no zonal error • Measure time instead of positions (and control very accurately the transformation) • Average the signal over several 10.000s pixels (good for photometry too) • Spectro-photometry • provide colors and low-resolution spectra (—> classification) for all sources • Radial velocities • Add the 3rd dimension of motions in the Galaxy + automated source detection on board webinar P. Tanga – Gaia and the Solar System 14 Gaia does not produce images ~0.38 as • (Except for testing in a special mode) • Operates in TDI mode (line period 1 ms) • Small windows read from the CCD around the sources • 2D windows are binned across scan —> 1 D data sample ~1 as (typ. 6 pixels) • on board lossless compression • Fundamental measurement: crossing time of a fiducial line on the CCD by the brightness peak of a source webinar P. Tanga – Gaia and the Solar System 15 Gaia produces unusual epoch astrometry • In the along scan direction the typical accuracy is a small fraction of a pixel (~1 mas) • Across scan it is of the order of a pixel (~100 mas) ~100 mas <1 mas Dec RA • When rotated to (RA, dec) this results in highly correlated uncertainties • This is not (very) relevant for stars • It is fundamental for asteroids! Pay attention to the covariance matrix webinar P. Tanga – Gaia and the Solar System 16 The Data Processing and Analysis Consortium - since 2007 webinar P. Tanga – Gaia and the Solar System 17 Gaia data - when? GDR1: star positions + Tycho-Gaia Astrometric Solution 40 mas GDR2: star positions + parallaxes + proper motions asteroid astrometry 10 mas Final release 2 mas sept. 2016 Apr 2018 2022 webinar P. Tanga – Gaia and the Solar System 18 GDR1: brightness accuracy This plot shows the distribution of the estimated uncertainties on the weighted mean G-band photometry as a function of magnitude. The colours indicate the density of data points, from low (red) to high (blue) on a logarithmic scale. Credits: ESA/Gaia/DPAC webinar P. Tanga – Gaia and the Solar System 19 GDR1: parallax accuracy (TGAS) webinar P. Tanga – Gaia and the Solar System 20 GDR1: position errors webinar P. Tanga – Gaia and the Solar System 21 Gaia Archive https://gea.esac.esa.int/archive/ webinar P. Tanga – Gaia and the Solar System 22 The Solar System and Gaia webinar P. Tanga – Gaia and the Solar System 23 What Gaia observes • What Gaia observes = all small objects at V < 20.5 –350.000 asteroids( >700.000 known today) –comets, TNOs –small planetary satellites • Why we are interested –small bodies record the history of the Solar System –very poorly known properties: • a few 1000s spectra, 10s masses, 100k sizes, ~400 shapes webinar P. Tanga – Gaia and the Solar System 24 Where Gaia observes unobservable ~70 observations per object • Discovery space: • Low elongations (~45-60°) • Inner Earth Objects (~unknown) • Other NEOs unobservable • Some MBAs webinar P. Tanga – Gaia and the Solar System 25 What Gaia observes: how big Kuiper Belt NEA Jupiter Trojans MBO webinar P. Tanga – Gaia and the Solar System 26 Gaia single-epoch astrometric accuracyJ. Desmars et al.: Statistical and numerical study of asteroid orbital uncertainty Table 4. Statistics of di↵erent measurements provided by the MPC database for numbered and unnumbered asteroids. final attitude and calibration, single FoV (9 positions) transit, point-like source Code Type Number Percentage Timespan C CCD1 mas 88 546 921 94.12% 1986–2012 S/s Space observation 4 006 572 4.26% 1994–2011 HST 3544 0.00% 1994–2010 Spitzer 114 0.00% 2004–2004 WISE 4 002 914 4.25% 2010–2011 A Observations from B1950.0 converted to J2000.0 647 690 0.69% 1802–1999 c Corrected without republication CCD observation 462 065 0.49% 1991–2007 P Photographic 352 449 0.37% 1898–2012 T Meridian or transit circle0.1 mas 26 968 0.03% 1984–2005 X/x Discovery observation 16 741 0.02% 1845–2010 M Micrometer 12 081 0.01% 1845–1954 HHipparcos geocentric observation 5494 0.01% 1989–1993 R Radar observation 2901 0.00% 1968–2012 E Occultations derived observation 1737 0.00% 1961–2012 V Roving observer observation 388 0.00% 2000–2012 n Mini-normal place derived from averaging observations from video frames 105 0.00% 2009–2012 e Encoder 16 0.00% 1993–1995 Table 5. Accuracy of measurements for numbered asteroids from the AstDyS2 database. Type Name Number of Percentage of Accuracy measurement accepted measurement C CCD 79 569 190 99.49% 0.388 arcsec S Wise 1 526 466 99.86% 0.583 arcsec random errors S Hubble Space Telescope 867 96.54% 0.585 arcsec S Spitzer 48 33.33% 1.673 arcsec + systematic A B1950 to J2000 632 428 82.17% 1.170 arcsec cObservations Corrected CCD observationin the AstDys 423 792 service (Univ. 99.70% Pisa) 0.507 arcsec P Photographic 346 947 93.38% 1.084 arcsec T Meridian/transit circle 26 968 100.00% 0.250 arcsec M Micrometer 12 081 94.56% 1.742 arcsec X Discovery observation 9520webinar 0.81% 0.898 arcsec HHipparcos observation 5494 100.00% 0.148 arcsec E Occultations 1736 100.00% 0.085 arcsec R Ranging 612 96.41% 3.325 km 1 R Doppler 432 99.07% 6.660 km s− V Roving observer 372 49.73% 0.822 arcsec e Encoder 16 100.00% 0.558 arcsec n video frame 12 100.00% 0.319 arcsec the residual (O–C) of each measurement. All the observations asteroid detection and the mission has detected 157 000 aster- of all numbered asteroids9 have been compiled and the ac- oids, including more than 500 NEO (Mainzer et al. 2011). curacy of each measurement has been estimated by comput- ing a weighted10 root mean square of all the residuals of the measurement. 4.2. Impact of astrometric measurements on orbit uncertainty – the Apophis example Table 5 provides the number, the percentage of accepted measurement, and the estimated accuracy for each kind of ob- In order to quantify the impact of a type of measurement on the servation. After radar measurements, observations derived from orbital uncertainty of an asteroid, we specifically dealt with the occultations and Hipparcos geocentric observations appear to asteroid Apophis. This particular object belongs to the PHA fam- be the most accurate (about 0.08–0.15 arcsec). Recent mea- ily and is known to be the most threatening object of the last surements such as CCD observations or meridian circle ob- decade since it is the only asteroid that reached level 4 of the servations are accurate to between 0.2–0.4 arcsec. Older mea- Torino scale for potential impact with the Earth in April 2029 surements, such as photographic or micrometric measures, are (Sansaturio & Arratia 2008). Since new observations (optical less accurate (1.0–1.8 arcsec). Surprisingly, observations from and radar) ruled out every possibility of impact in 2029, this spacecraft (HST, Spitzer or WISE) are not any more accurate threat turned out to be a close encounter within 5.64 R of the ⊕ than ground-based data.
Load more

Recommended publications
  • 174 Minor Planet Bulletin 47 (2020) DETERMINING the ROTATIONAL
    174 DETERMINING THE ROTATIONAL PERIODS AND LIGHTCURVES OF MAIN BELT ASTEROIDS Shandi Groezinger Kent Montgomery Texas A&M University-Commerce P.O. Box 3011 Commerce, TX 75429-3011 [email protected] (Received: 2020 Feb 21 Revised: 2020 March 20) Lightcurves and rotational periods are presented for six main-belt asteroids. The rotational periods determined are 970 Primula (2.777 ± 0.001 h), 1103 Sequoia (3.1125 ± 0.0004 h), 1160 Illyria (4.103 ± 0.002 h), 1188 Gothlandia (3.52 ± 0.05 h), 1831 Nicholson (3.215 ± 0.004 h) and (11230) 1999 JV57 (7.090 ± 0.003 h). The purpose of this research was to create lightcurves and determine the rotational periods of six asteroids: 970 Primula, 1103 Sequoia, 1160 Illyria, 1188 Gothlandia, 1831 Nicholson and (11230) 1999 JV57. Asteroids were selected for this study from a website that catalogues all known asteroids (CALL). For an asteroid to be chosen in this study, it has to meet the requirements of brightness, declination, and opposition date. For optimum signal to noise ratio (SNR), asteroids of apparent magnitude of 16 or lower were chosen. Asteroids with positive declinations were chosen due to using telescopes located in the northern hemisphere. The data for all the asteroids was typically taken within two weeks from their opposition dates. This would ensure a maximum number of images each night. Asteroid 970 Primula was discovered by Reinmuth, K. at Heidelberg in 1921. This asteroid has an orbital eccentricity of 0.2715 and a semi-major axis of 2.5599 AU (JPL). Asteroid 1103 Sequoia was discovered in 1928 by Baade, W.
    [Show full text]
  • ESO's VLT Sphere and DAMIT
    ESO’s VLT Sphere and DAMIT ESO’s VLT SPHERE (using adaptive optics) and Joseph Durech (DAMIT) have a program to observe asteroids and collect light curve data to develop rotating 3D models with respect to time. Up till now, due to the limitations of modelling software, only convex profiles were produced. The aim is to reconstruct reliable nonconvex models of about 40 asteroids. Below is a list of targets that will be observed by SPHERE, for which detailed nonconvex shapes will be constructed. Special request by Joseph Durech: “If some of these asteroids have in next let's say two years some favourable occultations, it would be nice to combine the occultation chords with AO and light curves to improve the models.” 2 Pallas, 7 Iris, 8 Flora, 10 Hygiea, 11 Parthenope, 13 Egeria, 15 Eunomia, 16 Psyche, 18 Melpomene, 19 Fortuna, 20 Massalia, 22 Kalliope, 24 Themis, 29 Amphitrite, 31 Euphrosyne, 40 Harmonia, 41 Daphne, 51 Nemausa, 52 Europa, 59 Elpis, 65 Cybele, 87 Sylvia, 88 Thisbe, 89 Julia, 96 Aegle, 105 Artemis, 128 Nemesis, 145 Adeona, 187 Lamberta, 211 Isolda, 324 Bamberga, 354 Eleonora, 451 Patientia, 476 Hedwig, 511 Davida, 532 Herculina, 596 Scheila, 704 Interamnia Occultation Event: Asteroid 10 Hygiea – Sun 26th Feb 16h37m UT The magnitude 11 asteroid 10 Hygiea is expected to occult the magnitude 12.5 star 2UCAC 21608371 on Sunday 26th Feb 16h37m UT (= Mon 3:37am). Magnitude drop of 0.24 will require video. DAMIT asteroid model of 10 Hygiea - Astronomy Institute of the Charles University: Josef Ďurech, Vojtěch Sidorin Hygiea is the fourth-largest asteroid (largest is Ceres ~ 945kms) in the Solar System by volume and mass, and it is located in the asteroid belt about 400 million kms away.
    [Show full text]
  • Occultation Newsletter Volume 8, Number 4
    Volume 12, Number 1 January 2005 $5.00 North Am./$6.25 Other International Occultation Timing Association, Inc. (IOTA) In this Issue Article Page The Largest Members Of Our Solar System – 2005 . 4 Resources Page What to Send to Whom . 3 Membership and Subscription Information . 3 IOTA Publications. 3 The Offices and Officers of IOTA . .11 IOTA European Section (IOTA/ES) . .11 IOTA on the World Wide Web. Back Cover ON THE COVER: Steve Preston posted a prediction for the occultation of a 10.8-magnitude star in Orion, about 3° from Betelgeuse, by the asteroid (238) Hypatia, which had an expected diameter of 148 km. The predicted path passed over the San Francisco Bay area, and that turned out to be quite accurate, with only a small shift towards the north, enough to leave Richard Nolthenius, observing visually from the coast northwest of Santa Cruz, to have a miss. But farther north, three other observers video recorded the occultation from their homes, and they were fortuitously located to define three well- spaced chords across the asteroid to accurately measure its shape and location relative to the star, as shown in the figure. The dashed lines show the axes of the fitted ellipse, produced by Dave Herald’s WinOccult program. This demonstrates the good results that can be obtained by a few dedicated observers with a relatively faint star; a bright star and/or many observers are not always necessary to obtain solid useful observations. – David Dunham Publication Date for this issue: July 2005 Please note: The date shown on the cover is for subscription purposes only and does not reflect the actual publication date.
    [Show full text]
  • ESO Call for Proposals – P109 Proposal Deadline: 23 September 2021, 12:00 Noon CEST * Call for Proposals
    ESO Call for Proposals – P109 Proposal Deadline: 23 September 2021, 12:00 noon CEST * Call for Proposals ESO Period 109 Proposal Deadline: 23 September 2021, 12:00 noon Central European Summer Time Issued 26 August 2021 * Preparation of the ESO Call for Proposals is the responsibility of the ESO Observing Programmes Office (OPO). For questions regarding preparation and submission of proposals to ESO telescopes, please submit your enquiries through the ESO Helpdesk. The ESO Call for Proposals document is a fully linked pdf file with bookmarks that can be viewed with Adobe Acrobat Reader 4.0 or higher. Internal document links appear in red and external links appear in blue. Links are clickable and will navigate the reader through the document (internal links) or will open a web browser (external links). ESO Call for Proposals Editor: Dimitri A. Gadotti Approved: Xavier Barcons Director General v Contents I Phase 1 Instructions1 1 ESO Proposals Invited1 1.1 Important recent changes (since Periods 107 and 108)..................2 1.1.1 General.......................................2 1.1.2 Paranal.......................................3 1.1.3 La Silla.......................................5 1.1.4 Chajnantor.....................................5 1.2 Important reminders....................................6 1.2.1 General.......................................6 1.2.2 Paranal.......................................7 1.2.3 La Silla.......................................9 1.2.4 Chajnantor.....................................9 1.3 Changes foreseen in the upcoming Periods........................ 10 2 Getting Started 10 2.1 Support for VLTI programmes.............................. 11 2.2 Exposure Time Calculators................................ 11 2.3 The p1 proposal submission tool............................. 11 2.3.1 Important notes.................................. 12 2.4 Proposal Submission.................................... 13 3 Visitor Instruments 13 II Proposal Types, Policies, and Procedures 14 4 Proposal Types 14 4.1 Normal Programmes...................................
    [Show full text]
  • Comet Hitchhiker
    Comet Hitchhiker NIAC Phase I Final Report June 30, 2015 Masahiro Ono, Marco Quadrelli, Gregory Lantoine, Paul Backes, Alejandro Lopez Ortega, H˚avard Grip, Chen-Wan Yen Jet Propulsion Laboratory, California Institute of Technology David Jewitt University of California, Los Angeles Copyright 2015. All rights reserved. Mission Concept - Pre-decisional - for Planning and Discussion Purposes Only. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration, and in part at University of California, Los Angeles. Comet Hitchhiker NASA Innovative Advanced Concepts Preface Yes, of course the Hitchhiker’s Guide to the Galaxy was in my mind when I came up with a concept of a tethered spacecraft hitching rides on small bodies, which I named Comet Hitchhiker. Well, this NASA-funded study is not exactly about traveling through the Galaxy; it is rather about exploring our own Solar System, which may sound a bit less exciting than visiting extraterrestrial civilizations, building a hyperspace bypass, or dining in the Restaurant at the End of the Universe. However, for the “primitive ape-descended life forms that have just begun exploring the universe merely a half century or so ago, our Solar System is still full of intellectually inspiring mysteries. So far the majority of manned and unmanned Solar System travelers solely depend on a fire breathing device called rocket, which is known to have terrible fuel efficiency. You might think there is no way other than using the gas-guzzler to accelerate or decelerate in an empty vacuum space.
    [Show full text]
  • When Artemis Talks, Johannes Kepler Listens 27 January 2011
    When Artemis talks, Johannes Kepler listens 27 January 2011 be shared between Artemis and NASA's Tracking and Data Relay Satellite System (TDRSS). The first ATV mission was also supported by Artemis, in 2008. Working in parallel with TDRSS, Artemis was used as the main relay while ATV was attached to the Station and provided back up for commands and telemetry during rendezvous, docking, undocking and reentry. Artemis will provide communications between Johannes Kepler and the ATV Control Centre (ATV-CC) in Toulouse, France. Hovering some 36 000 km above the equator at 21.4ºE, Artemis will route telemetry and commands to and from the control centre whenever the satellite sees the International Space Station or ATV. During every ATV-2 orbit, there is close to 40 minutes of continuous contact. Credit: ESA Credits: ESA/J.Huart After Ariane 5 lofts ATV Johannes Kepler into Artemis will again provide dedicated support to ATV space on 15 February, ESA's Artemis data relay throughout the free-flying phase of its mission up to satellite will be ready for action. the docking with the Station. TDRSS is the backup to Artemis during the attached phase, while Artemis Artemis will provide communications between will back up TDRSS during the other phases and in Johannes Kepler and the ATV Control Centre (ATV- emergency situations. CC) in Toulouse, France. Hovering some 36 000 km above the equator at 21.4ºE, Artemis will route Such was the case on 11 September 2008, when telemetry and commands to and from the control the Artemis Mission Control Centre provided centre whenever the satellite sees the International emergency support to ATV-1 after Hurricane Ike Space Station or ATV.
    [Show full text]
  • Envisat and MERIS Status
    MERIS US Workshop 14 July 2008 MERIS US Workshop, Silver Spring, July 14th, 2008 MERIS US Workshop Agenda a.m. ENVISAT/MERIS mission status, access to MERIS data 08:10-08:55 H. Laur (ESA) and distribution policy 08:55-09:10 Discussion Examples of the use of MERIS data in marine & land 09:10-09:40 P. Regner (ESA) applications 09:40-10:00 B. Arnone (NRL) Examples of MERIS data use for U.S. applications 10:00-10:20 S. Delwart (ESA) MERIS instrument overview 10:20-10:40 S. Delwart Instrument characterization overview 10:40-10:55 Discussion 10:55-11:10 Coffee break 11:10-11:30 S. Delwart Instrument calibration methods and results 11:30-11:50 Discussion 11:50-13:20 Lunch break MERIS US Workshop, Silver Spring, July 14th, 2008 MERIS US Workshop Agenda p.m. 13:20-13:50 L. Bourg (ACRI) Level 1 processing 13:50-14:10 Discussion 14:10-14:30 S. Delwart Vicarious calibration methods and results 14:30-14:50 Discussion 14:50-15:10 L. Bourg Overview Level 2 products 15:10-15:25 Coffee break 15:25-16:25 L. Bourg Level 2 processing 16:25-17:10 Discussion 17:10-17:25 P. Regner BEAM Toolbox 17:25-17:40 H. Laur Plans and status of the OLCI onboard GMES Sentinel-3 17:40-18:00 Discussion MERIS US Workshop, Silver Spring, July 14th, 2008 MERIS US Workshop, July 14th, 2008, Washington (USA) ENVISAT / MERIS mission status, access to MERIS data and distribution policy Henri LAUR Envisat Mission Manager & Head of EO Missions Management Office MERIS US Workshop, Silver Spring, July 14th, 2008 ESA: the European Space Agency The purpose of ESA: An inter-governmental
    [Show full text]
  • A Low Density of 0.8 G Cm-3 for the Trojan Binary Asteroid 617 Patroclus
    Publisher: NPG; Journal: Nature:Nature; Article Type: Physics letter DOI: 10.1038/nature04350 A low density of 0.8 g cm−3 for the Trojan binary asteroid 617 Patroclus Franck Marchis1, Daniel Hestroffer2, Pascal Descamps2, Jérôme Berthier2, Antonin H. Bouchez3, Randall D. Campbell3, Jason C. Y. Chin3, Marcos A. van Dam3, Scott K. Hartman3, Erik M. Johansson3, Robert E. Lafon3, David Le Mignant3, Imke de Pater1, Paul J. Stomski3, Doug M. Summers3, Frederic Vachier2, Peter L. Wizinovich3 & Michael H. Wong1 1Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, California 94720, USA. 2Institut de Mécanique Céleste et de Calculs des Éphémérides, UMR CNRS 8028, Observatoire de Paris, 77 Avenue Denfert-Rochereau, F-75014 Paris, France. 3W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, Hawaii 96743, USA. The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 stable Lagrange points of the Jupiter–Sun system (leading and following Jupiter by 60°). The asteroid 617 Patroclus is the only known binary Trojan1. The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system’s centre of mass, describing a roughly circular orbit. Using this orbital information, combined with thermal measurements to estimate +0.2 −3 the size of the components, we derive a very low density of 0.8 −0.1 g cm . The components of 617 Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the Solar System2.
    [Show full text]
  • 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.
    [Show full text]
  • IMPLICATIONS of ASTEROIDAL SATELLITES. W.J. Merline1 and C.R
    64th Annual Meteoritical Society Meeting (2001) 5457.pdf IMPLICATIONS OF ASTEROIDAL SATELLITES. W.J. Merline1 and C.R. Chapman2, 1Southwest Research Institute ([email protected]), 2Southwest Research Institute ([email protected]) There has been a recent revolution in asteroid astron- strange objects like the highly elongated metallic ob- omy that may have important implications for meteor- ject Kleopatra and the recently discovered distant sat- ite parent bodies. In short, in the last 8 years, it has ellite of a Kuiper Belt Object, could be a remnant from been found that numerous asteroids are double bodies accretionary processes. or have small satellites orbiting about them. The first one to be discovered (the 1.8 km moonlet found by the In thinking about where meteorites come from, it Galileo spacecraft to be orbiting around 31 km-sized would help parent-body modelers to have a mental Ida during a 1993 flyby) could have been a fluke, since framework that includes the kinds of configurations the accepted theoretical perspective at the time was now being discovered and the potential processes these that such satellites would be very rare or absent. How- bodies have been through before delivering meteorites ever, we now know that at least several percent of to our collections. Certainly there are implications main-belt asteroids are binaries and that a large per- from the existence of asteroidal satellites for the char- centage of Earth-approaching asteroids are binaries. acter of rubble piles, exposure ages of asteroidal rocks, and so on. The existence of double impact craters on It is not known with certainty how these satellites are the Earth and other planets may now have a more natu- created, but it is likely to be due to several different ral explanation.
    [Show full text]
  • A Call for a New Human Missions Cost Model
    A Call For A New Human Missions Cost Model NASA 2019 Cost and Schedule Analysis Symposium NASA Johnson Space Center, August 13-15, 2019 Joseph Hamaker, PhD Christian Smart, PhD Galorath Human Missions Cost Model Advocates Dr. Joseph Hamaker Dr. Christian Smart Director, NASA and DoD Programs Chief Scientist • Former Director for Cost Analytics • Founding Director of the Cost and Parametric Estimating for the Analysis Division at NASA U.S. Missile Defense Agency Headquarters • Oversaw development of the • Originator of NASA’s NAFCOM NASA/Air Force Cost Model cost model, the NASA QuickCost (NAFCOM) Model, the NASA Cost Analysis • Provides subject matter expertise to Data Requirement and the NASA NASA Headquarters, DARPA, and ONCE database Space Development Agency • Recognized expert on parametrics 2 Agenda Historical human space projects Why consider a new Human Missions Cost Model Database for a Human Missions Cost Model • NASA has over 50 years of Human Space Missions experience • NASA’s International Partners have accomplished additional projects . • There are around 70 projects that can provide cost and schedule data • This talk will explore how that data might be assembled to form the basis for a Human Missions Cost Model WHY A NEW HUMAN MISSIONS COST MODEL? NASA’s Artemis Program plans to Artemis needs cost and schedule land humans on the moon by 2024 estimates Lots of projects: Lunar Gateway, Existing tools have some Orion, landers, SLS, commercially applicability but it seems obvious provided elements (which we may (to us) that a dedicated HMCM is want to independently estimate) needed Some of these elements have And this can be done—all we ongoing cost trajectories (e.g.
    [Show full text]
  • The Veritas and Themis Asteroid Families: 5-14Μm Spectra with The
    Icarus 269 (2016) 62–74 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus The Veritas and Themis asteroid families: 5–14 μm spectra with the Spitzer Space Telescope Zoe A. Landsman a,∗, Javier Licandro b,c, Humberto Campins a, Julie Ziffer d, Mario de Prá e, Dale P. Cruikshank f a Department of Physics, University of Central Florida, 4111 Libra Drive, PS 430, Orlando, FL 32826, United States b Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38205, La Laguna, Tenerife, Spain c Departamento de Astrofísica, Universidad de La Laguna, E-38205, La Laguna, Tenerife, Spain d Department of Physics, University of Southern Maine, 96 Falmouth St, Portland, ME 04103, United States e Observatório Nacional, R. General José Cristino, 77 - Imperial de São Cristóvão, Rio de Janeiro, RJ 20921-400, Brazil f NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035, United States article info abstract Article history: Spectroscopic investigations of primitive asteroid families constrain family evolution and composition and Received 18 October 2015 conditions in the solar nebula, and reveal information about past and present distributions of volatiles in Revised 30 December 2015 the solar system. Visible and near-infrared studies of primitive asteroid families have shown spectral di- Accepted 8 January 2016 versity between and within families. Here, we aim to better understand the composition and physical Available online 14 January 2016 properties of two primitive families with vastly different ages: ancient Themis (∼2.5 Gyr) and young Ver- Keywords: itas (∼8 Myr). We analyzed the 5 – 14 μm Spitzer Space Telescope spectra of 11 Themis-family asteroids, Asteroids including eight previously studied by Licandro et al.
    [Show full text]