Isotopic Ratios in Outbursting Comet C/2015 ER61
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Observational Constraints on Surface Characteristics of Comet Nuclei
Observational Constraints on Surface Characteristics of Comet Nuclei Humberto Campins ([email protected] u) Lunar and Planetary Laboratory, University of Arizona Yanga Fernandez University of Hawai'i Abstract. Direct observations of the nuclear surfaces of comets have b een dicult; however a growing number of studies are overcoming observational challenges and yielding new information on cometary surfaces. In this review, we fo cus on recent determi- nations of the alb edos, re ectances, and thermal inertias of comet nuclei. There is not much diversity in the geometric alb edo of the comet nuclei observed so far (a range of 0.025 to 0.06). There is a greater diversity of alb edos among the Centaurs, and the sample of prop erly observed TNOs (2) is still to o small. Based on their alb edos and Tisserand invariants, Fernandez et al. (2001) estimate that ab out 5% of the near-Earth asteroids have a cometary origin, and place an upp er limit of 10%. The agreement between this estimate and two other indep endent metho ds provide the strongest constraint to date on the fraction of ob jects that comets contribute to the p opulation of near-Earth asteroids. There is a diversity of visible colors among comets, extinct comet candidates, Centaurs and TNOs. Comet nuclei are clearly not as red as the reddest Centaurs and TNOs. What Jewitt (2002) calls ultra-red matter seems to be absent from the surfaces of comet nuclei. Rotationally resolved observations of b oth colors and alb edos are needed to disentangle the e ects of rotational variability from other intrinsic qualities. -
KAREN J. MEECH February 7, 2019 Astronomer
BIOGRAPHICAL SKETCH – KAREN J. MEECH February 7, 2019 Astronomer Institute for Astronomy Tel: 1-808-956-6828 2680 Woodlawn Drive Fax: 1-808-956-4532 Honolulu, HI 96822-1839 [email protected] PROFESSIONAL PREPARATION Rice University Space Physics B.A. 1981 Massachusetts Institute of Tech. Planetary Astronomy Ph.D. 1987 APPOINTMENTS 2018 – present Graduate Chair 2000 – present Astronomer, Institute for Astronomy, University of Hawaii 1992-2000 Associate Astronomer, Institute for Astronomy, University of Hawaii 1987-1992 Assistant Astronomer, Institute for Astronomy, University of Hawaii 1982-1987 Graduate Research & Teaching Assistant, Massachusetts Inst. Tech. 1981-1982 Research Specialist, AAVSO and Massachusetts Institute of Technology AWARDS 2018 ARCs Scientist of the Year 2015 University of Hawai’i Regent’s Medal for Research Excellence 2013 Director’s Research Excellence Award 2011 NASA Group Achievement Award for the EPOXI Project Team 2011 NASA Group Achievement Award for EPOXI & Stardust-NExT Missions 2009 William Tylor Olcott Distinguished Service Award of the American Association of Variable Star Observers 2006-8 National Academy of Science/Kavli Foundation Fellow 2005 NASA Group Achievement Award for the Stardust Flight Team 1996 Asteroid 4367 named Meech 1994 American Astronomical Society / DPS Harold C. Urey Prize 1988 Annie Jump Cannon Award 1981 Heaps Physics Prize RESEARCH FIELD AND ACTIVITIES • Developed a Discovery mission concept to explore the origin of Earth’s water. • Co-Investigator on the Deep Impact, Stardust-NeXT and EPOXI missions, leading the Earth-based observing campaigns for all three. • Leads the UH Astrobiology Research interdisciplinary program, overseeing ~30 postdocs and coordinating the research with ~20 local faculty and international partners. -
Investigation of Dust and Water Ice in Comet 9P/Tempel 1 from Spitzer Observations of the Deep Impact Event
A&A 542, A119 (2012) Astronomy DOI: 10.1051/0004-6361/201118718 & c ESO 2012 Astrophysics Investigation of dust and water ice in comet 9P/Tempel 1 from Spitzer observations of the Deep Impact event A. Gicquel1, D. Bockelée-Morvan1 ,V.V.Zakharov1,2,M.S.Kelley3, C. E. Woodward4, and D. H. Wooden5 1 LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France e-mail: [adeline.gicquel;dominique.bockelee;vladimir.zakharov]@obspm.fr 2 Gordien Strato, France 3 Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA e-mail: [email protected] 4 Minnesota Institute for Astrophysics, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA e-mail: [email protected] 5 NASA Ames Research Center, Space Science Division, USA e-mail: [email protected] Received 22 December 2011 / Accepted 9 February 2012 ABSTRACT Context. The Spitzer spacecraft monitored the Deep Impact event on 2005 July 4 providing unique infrared spectrophotometric data that enabled exploration of comet 9P/Tempel 1’s activity and coma properties prior to and after the collision of the impactor. Aims. The time series of spectra take with the Spitzer Infrared Spectrograph (IRS) show fluorescence emission of the H2O ν2 band at 6.4 μm superimposed on the dust thermal continuum. These data provide constraints on the properties of the dust ejecta cloud (dust size distribution, velocity, and mass), as well as on the water component (origin and mass). Our goal is to determine the dust-to-ice ratio of the material ejected from the impact site. -
Project Pan-STARRS and the Outer Solar System
Project Pan-STARRS and the Outer Solar System David Jewitt Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 ABSTRACT Pan-STARRS, a funded project to repeatedly survey the entire visible sky to faint limiting magnitudes (mR ∼ 24), will have a substantial impact on the study of the Kuiper Belt and outer solar system. We briefly review the Pan- STARRS design philosophy and sketch some of the planetary science areas in which we expect this facility to make its mark. Pan-STARRS will find ∼20,000 Kuiper Belt Objects within the first year of operation and will obtain accurate astrometry for all of them on a weekly or faster cycle. We expect that it will revolutionise our knowledge of the contents and dynamical structure of the outer solar system. Subject headings: Surveys, Kuiper Belt, comets 1. Introduction to Pan-STARRS Project Pan-STARRS (short for Panoramic Survey Telescope and Rapid Response Sys- tem) is a collaboration between the University of Hawaii's Institute for Astronomy, the MIT Lincoln Laboratory, the Maui High Performance Computer Center, and Science Ap- plications International Corporation. The Principal Investigator for the project, for which funding started in the fall of 2002, is Nick Kaiser of the Institute for Astronomy. Operations should begin by 2007. The science objectives of Pan-STARRS span the full range from planetary to cosmolog- ical. The instrument will conduct a survey of the solar system that is staggering in power compared to anything yet attempted. A useful measure of the raw survey power, SP , of a telescope is given by AΩ SP = (1) θ2 where A [m2] is the collecting area of the telescope primary, Ω [deg2] is the solid angle that is imaged and θ [arcsec] is the full-width at half maximum (FWHM) of the images { 2 { produced by the telescope. -
Characterization of the Physical Properties of the ROSETTA Target Comet 67P/Churyumov-Gerasimenko
Characterization of the physical properties of the ROSETTA target comet 67P/Churyumov-Gerasimenko Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades einer Doktorin der Naturwissenschaften (Dr.rer.nat.) genehmigte Dissertation von Cecilia Tubiana aus Moncalieri/Italien 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: Prof. Dr. Michael A’Hearn eingereicht am: 18 August 2008 mündliche Prüfung (Disputation) am: 30 Oktober 2008 ISBN 978-3-936586-89-3 Copernicus Publications 2008 http://publications.copernicus.org c Cecilia Tubiana Printed in Germany Contents Summary 7 1 Comets: introduction 11 1.1 Physical properties of cometary nuclei . 15 1.1.1 Size and shape of a cometary nucleus . 18 1.1.2 Rotational period of a cometary nucleus . 22 1.1.3 Albedo of cometary nuclei . 24 1.1.4 Bulk density of cometary nuclei . 25 1.1.5 Colors indices and spectra of the nucleus . 25 1.2 Dust trail and neck-line . 27 2 67P/Churyumov-Gerasimenko and the ESA’s ROSETTA mission 29 2.1 Discovery and orbital evolution . 29 2.2 Nucleus properties . 30 2.3 Annual light curve . 32 2.4 Gas and dust production . 32 2.5 Coma features, trail and neck-line . 35 2.6 ESA’s ROSETTA mission . 35 2.7 Motivations of the thesis . 39 3 Observing strategy and performance of the observations of 67P/C-G 41 3.1 Observations: strategy and preparation . -
A Possible Naked-Eye Comet in March 9 February 2013, by Dr
A possible naked-eye comet in March 9 February 2013, by Dr. Tony Phillips the Big Dipper. "But" says Karl Battams of the Naval Research Lab, "prepare to be surprised. A new comet from the Oort Cloud is always an unknown quantity equally capable of spectacular displays or dismal failures." The Oort cloud is named after the 20th-century Dutch astronomer Jan Oort, who argued that such a cloud must exist to account for all the "fresh" comets that fall through the inner solar system. Unaltered by warmth and sunlight, the distant comets of the Oort cloud are like time capsules, harboring frozen gases and primitive, dusty material drawn from the original solar nebula 4.5 billion years ago. When these comets occasionally fall toward the sun, they bring their virgin ices with them. An artist's concept of the Oort cloud. Credit: NASA Because this is Comet Pan-STARRS first visit, it has never been tested by the fierce heat and gravitational pull of the sun. "Almost anything could Far beyond the orbits of Neptune and Pluto, where happen," says Battams. On one hand, the comet the sun is a pinprick of light not much brighter than could fall apart—a fizzling disappointment. On the other stars, a vast swarm of icy bodies circles the other hand, fresh veins of frozen material could solar system. Astronomers call it the "Oort Cloud," open up to spew garish jets of gas and dust into the and it is the source of some of history's finest night sky. comets. "Because of its small distance from the sun, Pan- One of them could be heading our way now. -
January 12-18, 2020
3# Ice & Stone 2020 Week 3: January 12-18, 2020 Presented by The Earthrise Institute This week in history JANUARY 12 13 14 15 16 17 18 JANUARY 12, 1910: A group of diamond miners in the Transvaal in South Africa spot a brilliant comet low in the predawn sky. This was the first sighting of what became known as the “Daylight Comet of 1910” (old style designations 1910a and 1910 I, new style designation C/1910 A1). It soon became one of the brightest comets of the entire 20th Century and will be featured as “Comet of the Week” in two weeks. JANUARY 12, 2005: NASA’S Deep Impact mission is launched from Cape Canaveral, Florida. Deep Impact would encounter Comet 9P/Tempel 1 in July of that year and – under the mission name “EPOXI” – would encounter Comet 103P/Hartley 2 in November 2010. Comet 9P/Tempel 1 is a future “Comet of the Week” and the Deep Impact mission – and its results – will be discussed in more detail at that time. JANUARY 12, 2007: Comet McNaught C/2006 P1, the brightest comet thus far of the 21st Century, passes through perihelion at a heliocentric distance of 0.171 AU. Comet McNaught is this week’s “Comet of the Week.” JANUARY 12 13 14 15 16 17 18 JANUARY 13, 1950: Jan Oort’s paper “The Structure of the Cloud of Comets Surrounding the Solar System, and a Hypothesis Concerning its Origin,” is published in the Bulletin of the Astronomical Institute of The Netherlands. In this paper Oort demonstrates that his calculations reveal the existence of a large population of comets enshrouding the solar system at heliocentric distances of tens of thousands of Astronomical Units. -
Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710
Bachelor Thesis University of Groningen Kapteyn Astronomical Institute Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710 August 5, 2019 Author: Rens Juris Tesink Supervisors: Kateryna Frantseva and Nickolas Oberg Abstract Context: Our Sun is thought to have an Oort cloud, a spherically symmetric shell of roughly 1011 comets orbiting with semi major axes between ∼ 5 × 103 AU and 1 × 105 AU. It is thought to be possible that other stars also possess comet clouds. Gliese 710 is a star expected to have a close encounter with the Sun in 1.35 Myrs. Aims: To simulate the comet clouds around the Sun and Gliese 710 and investigate the effect of the close encounter. Method: Two REBOUND N-body simulations were used with the help of Gaia DR2 data. Simulation 1 had a total integration time of 4 Myr, a time-step of 1 yr, and 10,000 comets in each comet cloud. And Simulation 2 had a total integration time of 80,000 yr, a time-step of 0.01 yr, and 100,000 comets in each comet cloud. Results: Simulation 2 revealed a 1.7% increase in the semi-major axis at time of closest approach and a population loss of 0.019% - 0.117% for the Oort cloud. There was no statistically significant net change of the inclination of the comets during this encounter and a 0.14% increase in the eccentricity at the time of closest approach. Contents 1 Introduction 3 1.1 Comets . .3 1.2 New comets and the Oort cloud . .5 1.3 Structure of the Oort cloud . -
The Orbit and Size-Frequency Distribution of Long Period Comets Observed by Pan-STARRS1
The Orbit and Size-Frequency Distribution of Long Period Comets Observed by Pan-STARRS1 Benjamin Boea, Robert Jedickea, Karen J. Meecha, Paul Wiegertb, Robert J. Weryka, K. C. Chambersa, L. Denneaua, N. Kaiserd, R.-P. Kudritzkia,c, E. A. Magniera, R. J. Wainscoata, C. Watersa aInstitute for Astronomy, University of Hawai`i, 2680 Woodlawn Drive, Honolulu, HI 96822, USA bThe University of Western Ontario, London, Ontario, Canada cMunich University Observatory, Munich, Germany dEcole´ Normale Sup´erieure, Paris, France. Abstract We introduce a new technique to estimate the comet nuclear size frequency distribution (SFD) that combines a cometary activity model with a survey simulation and apply it to 150 long period comets (LPC) detected by the Pan-STARRS1 near-Earth object survey. The debiased LPC size-frequency distribution is in agreement with previous estimates for large comets with nuclear diameter & 1 km but we measure a significant drop in the SFD slope for small objects with diameters < 1 km and approaching only 100 m diameter. Large objects have a slope αbig = 0:72 ± 0:09(stat:) ± 0:15(sys:) while small objects behave as αsmall = αHN 0:07 ± 0:03(stat:) ± 0:09(sys:) where the SFD is / 10 and HN represents the cometary nuclear absolute magnitude. The total number of LPCs that are > 1 km diameter and have perihelia q < 10 au is 0:46 ± 0:15 × 109 while there are only 2:4 ± 0:5(stat:) ± 2(sys:) × 109 objects with diameters > 100 m due to the shallow slope of the SFD for diameters < 1 km. We estimate that the total number of `potentially active' objects with diameters ≥ 1 km in the Oort cloud, objects that would be defined as LPCs if their perihelia evolved to < 10 au, is 12 (1:5±1)×10 with a combined mass of 1:3±0:9 M⊕. -
The History and Dynamics of Comet 9P/Tempel 1
The History and Dynamics of Comet 9P/Tempel 1 Donald K. Yeomans, Jon D. Giorgini and Steven R. Chesley 301-150, Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109, USA Submitted to Space Science Reviews, July xx, 2004 Suggested running head: History and Dynamics of Comet 9P/Tempel 1 Editorial correspondence to: Donald K. Yeomans 301-150 Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109-8099 [email protected] Tel. (818) 354 2127 FAX (818) 393 1159 Key words: Comets, Deep Impact, Space Missions, 9P/Tempel 1, cometary dynamics Abstract: Since its discovery in 1867, periodic comet 9P/Tempel 1 has been observed at 10 returns to perihelion, including all its returns since 1967. The observations for the seven apparitions beginning in 1967 have been fit with an orbit that includes only radial and transverse nongravitational accelerations that model the rocket-like thrusting introduced by the outgassing of the cometary nucleus. The successful nongravitational acceleration model did not assume any change in the comet’s ability to outgas from one apparition to the next and the outgassing was assumed to reach a maximum at perihelion. The success of this model over the 1967 – 2003 interval suggests that the comet’s spin axis is currently stable. Rough calculations suggest that the collision of the impactor released by the Deep Impact spacecraft will not provide a noticeable perturbation on the comet’s orbit nor will any new vent that is opened as a result of the impact provide a noticeable change in the comet’s nongravitational acceleration history. -
Outbursts on Comet 67P/Churyumov– Gerasimenko
EPSC Abstracts Vol. 13, EPSC-DPS2019-1920-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Outbursts on comet 67P/Churyumov– Gerasimenko Zhong-Yi Lin (1), Wing-Huen Ip (1), Jean-Baptiste Vincent (2) and the OSIRIS team (1) Institute of Astronomy, NCU, Taiwan ([email protected]) (2), Institute of Planetary Research, DLR, Berlin Germany Abstract the mechanism for this type of activity is still unknown. Fortunately, unlike the snap shots from the The optical, spectrocopic and infrared remote previous flyby observations, the OSIRIS imaging system (OSIRIS) onboard the Rosetta measurements can provide precise information on the spacecraft provided first-hand information on the timing and location of the outbursts via a time series outbursts from comet 67P/Churyumov–Gerasimenko. of high-resolution images. After the first detection in In this paper, we upgrade the investigation on the 2015 March, the OSIRIS wide-angle camera (WAC) physical properties of the outbursts from July 2015 to and narrow-angle camera (NAC) captured another September 2016. The new map of the source regions outburst in mid-July of 2015. Since then, many more from the detected outbursts has been used for the outbursts from the nightside and sunlit regions have comparison to the measurements from the other been detected, with most of their source regions onboard instruments. located in the Southern hemisphere of comet 67P. The detected outburst events show a variety of 1. Introduction morphological features that can be classified into three different types: broad fans, narrow jets and The optical, spectrocopic and infrared remote complex plumes. -
An Exocomet in the Fomalhaut System: Simulating Gas and Dust Emission in a Debris Disk
EPSC Abstracts Vol. 13, EPSC-DPS2019-1649-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. An exocomet in the Fomalhaut system: simulating gas and dust emission in a debris disk Maria Teresa Capria (1), Diego Turrini (1) and Edoardo Rognini (1) (1) INAF-IAPS, Rome, Italy (mariateresa.capria @inaf.it) Abstract by the sublimation of the ices and undergo the drag exerted by the escaping gas. The model is being used A thermophysical model is being used to simulate the to compute the amount of gas and dust released from behaviour of a cometary nucleus following an orbit the nucleus along an orbit, both in presence and in the Fomlhaut debris disc. We study the amount of absence of gas from the circumstellar disc. The CO gas and dust released during a typical orbit, and chosen orbit has the aphelion at 170 au and the compare them with the ALMA observations. We also perihelion at 140 au. We are willing to study the evaluate the survival of the body on a very long time amount of CO gas and dust released during a typical span. orbit, and compare these emissions with the ALMA observations. We are also willing to derive the total mass lost by the exocomet during an orbit and study 1. Introduction its long-time activity of the comet, in order to A number of debris disks around main sequence stars evaluate the survival of the body on a very long time have are now been identified [1], and in some of span.