KAREN J. MEECH February 7, 2019 Astronomer
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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. -
SPECIAL Comet Shoemaker-Levy 9 Collides with Jupiter
SL-9/JUPITER ENCOUNTER - SPECIAL Comet Shoemaker-Levy 9 Collides with Jupiter THE CONTINUATION OF A UNIQUE EXPERIENCE R.M. WEST, ESO-Garching After the Storm Six Hectic Days in July eration during the first nights and, as in other places, an extremely rich data The recent demise of comet Shoe ESO was but one of many profes material was secured. It quickly became maker-Levy 9, for simplicity often re sional observatories where observations evident that infrared observations, es ferred to as "SL-9", was indeed spectac had been planned long before the critical pecially imaging with the far-IR instru ular. The dramatic collision of its many period of the "SL-9" event, July 16-22, ment TIMMI at the 3.6-metre telescope, fragments with the giant planet Jupiter 1994. It is now clear that practically all were perfectly feasible also during day during six hectic days in July 1994 will major observatories in the world were in time, and in the end more than 120,000 pass into the annals of astronomy as volved in some way, via their telescopes, images were obtained with this facility. one of the most incredible events ever their scientists or both. The only excep The programmes at most of the other predicted and witnessed by members of tions may have been a few observing La Silla telescopes were also successful, this profession. And never before has a sites at the northernmost latitudes where and many more Gigabytes of data were remote astronomical event been so ac the bright summer nights and the very recorded with them. -
Disintegration of Active Asteroid P/2016 G1 (PANSTARRS) Olivier R
A&A 628, A48 (2019) https://doi.org/10.1051/0004-6361/201935868 Astronomy & © ESO 2019 Astrophysics Disintegration of active asteroid P/2016 G1 (PANSTARRS) Olivier R. Hainaut1, Jan T. Kleyna2, Karen J. Meech2, Mark Boslough3, Marco Micheli4,5, Richard Wainscoat2, Marielle Dela Cruz2, Jacqueline V. Keane2, Devendra K. Sahu6, and Bhuwan C. Bhatt6 1 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany e-mail: [email protected] 2 Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 3 University of NM – 1700 Lomas Blvd, NE. Suite 2200, Albuquerque, NM 87131-0001 USA 4 ESA SSA-NEO Coordination Centre, Largo Galileo Galilei, 1 00044 Frascati (RM), Italy 5 INAF – Osservatorio Astronomico di Roma, Via Frascati, 33, 00040 Monte Porzio Catone (RM), Italy 6 Indian Institute of Astrophysics, II Block, Koramangala, Bengaluru 560 034, India Received 10 May 2019 / Accepted 26 June 2019 ABSTRACT We report on the catastrophic disintegration of P/2016 G1 (PANSTARRS), an active asteroid, in April 2016. Deep images over three months show that the object is made up of a central concentration of fragments surrounded by an elongated coma, and presents previously unreported sharp arc-like and narrow linear features. The morphology and evolution of these characteristics independently point toward a brief event on 2016 March 6. The arc and the linear feature can be reproduced by large particles on a ring, moving at ∼2:5 m s−1. The expansion of the ring defines a cone with a ∼40◦ half-opening. We propose that the P/2016 G1 was hit by a small object which caused its (partial or total) disruption, and that the ring corresponds to large fragments ejected during the final stages of the crater formation. -
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. -
Early Observations of the Interstellar Comet 2I/Borisov
geosciences Article Early Observations of the Interstellar Comet 2I/Borisov Chien-Hsiu Lee NSF’s National Optical-Infrared Astronomy Research Laboratory, Tucson, AZ 85719, USA; [email protected]; Tel.: +1-520-318-8368 Received: 26 November 2019; Accepted: 11 December 2019; Published: 17 December 2019 Abstract: 2I/Borisov is the second ever interstellar object (ISO). It is very different from the first ISO ’Oumuamua by showing cometary activities, and hence provides a unique opportunity to study comets that are formed around other stars. Here we present early imaging and spectroscopic follow-ups to study its properties, which reveal an (up to) 5.9 km comet with an extended coma and a short tail. Our spectroscopic data do not reveal any emission lines between 4000–9000 Angstrom; nevertheless, we are able to put an upper limit on the flux of the C2 emission line, suggesting modest cometary activities at early epochs. These properties are similar to comets in the solar system, and suggest that 2I/Borisov—while from another star—is not too different from its solar siblings. Keywords: comets: general; comets: individual (2I/Borisov); solar system: formation 1. Introduction 2I/Borisov was first seen by Gennady Borisov on 30 August 2019. As more observations were conducted in the next few days, there was growing evidence that this might be an interstellar object (ISO), especially its large orbital eccentricity. However, the first astrometric measurements do not have enough timespan and are not of same quality, hence the high eccentricity is yet to be confirmed. This had all changed by 11 September; where more than 100 astrometric measurements over 12 days, Ref [1] pinned down the orbit elements of 2I/Borisov, with an eccentricity of 3.15 ± 0.13, hence confirming the interstellar nature. -
Photometric Study of Two Near-Earth Asteroids in the Sloan Digital Sky Survey Moving Objects Catalog
University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects January 2020 Photometric Study Of Two Near-Earth Asteroids In The Sloan Digital Sky Survey Moving Objects Catalog Christopher James Miko Follow this and additional works at: https://commons.und.edu/theses Recommended Citation Miko, Christopher James, "Photometric Study Of Two Near-Earth Asteroids In The Sloan Digital Sky Survey Moving Objects Catalog" (2020). Theses and Dissertations. 3287. https://commons.und.edu/theses/3287 This Thesis is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. PHOTOMETRIC STUDY OF TWO NEAR-EARTH ASTEROIDS IN THE SLOAN DIGITAL SKY SURVEY MOVING OBJECTS CATALOG by Christopher James Miko Bachelor of Science, Valparaiso University, 2013 A Thesis Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Master of Science Grand Forks, North Dakota August 2020 Copyright 2020 Christopher J. Miko ii Christopher J. Miko Name: Degree: Master of Science This document, submitted in partial fulfillment of the requirements for the degree from the University of North Dakota, has been read by the Faculty Advisory Committee under whom the work has been done and is hereby approved. ____________________________________ Dr. Ronald Fevig ____________________________________ Dr. Michael Gaffey ____________________________________ Dr. Wayne Barkhouse ____________________________________ Dr. Vishnu Reddy ____________________________________ ____________________________________ This document is being submitted by the appointed advisory committee as having met all the requirements of the School of Graduate Studies at the University of North Dakota and is hereby approved. -
Comet Section Observing Guide
Comet Section Observing Guide 1 The British Astronomical Association Comet Section www.britastro.org/comet BAA Comet Section Observing Guide Front cover image: C/1995 O1 (Hale-Bopp) by Geoffrey Johnstone on 1997 April 10. Back cover image: C/2011 W3 (Lovejoy) by Lester Barnes on 2011 December 23. © The British Astronomical Association 2018 2018 December (rev 4) 2 CONTENTS 1 Foreword .................................................................................................................................. 6 2 An introduction to comets ......................................................................................................... 7 2.1 Anatomy and origins ............................................................................................................................ 7 2.2 Naming .............................................................................................................................................. 12 2.3 Comet orbits ...................................................................................................................................... 13 2.4 Orbit evolution .................................................................................................................................... 15 2.5 Magnitudes ........................................................................................................................................ 18 3 Basic visual observation ........................................................................................................ -
Interstellar Comet 2I/Borisov
Interstellar comet 2I/Borisov Piotr Guzik1*, Michał Drahus1*, Krzysztof Rusek2, Wacław Waniak1, Giacomo Cannizzaro3,4, Inés Pastor-Marazuela5,6 1 Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland 2 AGH University of Science and Technology, al. Mickiewicza 30, Kraków 30-059, Poland 3 SRON, Netherlands Institute for Space Research, Sorbonnelaan, 2, NL-3584CA Utrecht, the Netherlands 4 Department of Astrophysics/IMAPP, Radboud University, P.O. Box 9010, 6500 GL Nijmegen, the Netherlands 5 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands 6 ASTRON, Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands * These authors contributed equally to this work. Interstellar comets penetrating through the Solar System were anticipated for decades1,2. The discovery of non-cometary 1I/‘Oumuamua by Pan-STARRS was therefore a huge surprise and puzzle. Furthermore, its physical properties turned out to be impossible to reconcile with Solar System objects3-5, which radically changed our view on interstellar minor bodies. Here, we report the identification of a new interstellar object which has an evidently cometary appearance. The body was identified by our data mining code in publicly available astrometric data. The data clearly show significant systematic deviation from what is expected for a parabolic orbit and are consistent with an enormous orbital eccentricity of 3.14 ± 0.14. Images taken by the William Herschel Telescope and Gemini North telescope show an extended coma and a faint, broad tail – the canonical signatures of cometary activity. The observed g’ and r’ magnitudes are equal to 19.32 ± 0.02 and 18.69 ± 0.02, respectively, implying g’-r’ color index of 0.63 ± 0.03, essentially the same as measured for the native Solar System comets. -
Initial Characterization of Interstellar Comet 2I/Borisov
Initial characterization of interstellar comet 2I/Borisov Piotr Guzik1*, Michał Drahus1*, Krzysztof Rusek2, Wacław Waniak1, Giacomo Cannizzaro3,4, Inés Pastor-Marazuela5,6 1 Astronomical Observatory, Jagiellonian University, Kraków, Poland 2 AGH University of Science and Technology, Kraków, Poland 3 SRON, Netherlands Institute for Space Research, Utrecht, the Netherlands 4 Department of Astrophysics/IMAPP, Radboud University, Nijmegen, the Netherlands 5 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Amsterdam, the Netherlands 6 ASTRON, Netherlands Institute for Radio Astronomy, Dwingeloo, the Netherlands * These authors contributed equally to this work; email: [email protected], [email protected] Interstellar comets penetrating through the Solar System had been anticipated for decades1,2. The discovery of asteroidal-looking ‘Oumuamua3,4 was thus a huge surprise and a puzzle. Furthermore, the physical properties of the ‘first scout’ turned out to be impossible to reconcile with Solar System objects4–6, challenging our view of interstellar minor bodies7,8. Here, we report the identification and early characterization of a new interstellar object, which has an evidently cometary appearance. The body was discovered by Gennady Borisov on 30 August 2019 UT and subsequently identified as hyperbolic by our data mining code in publicly available astrometric data. The initial orbital solution implies a very high hyperbolic excess speed of ~32 km s−1, consistent with ‘Oumuamua9 and theoretical predictions2,7. Images taken on 10 and 13 September 2019 UT with the William Herschel Telescope and Gemini North Telescope show an extended coma and a faint, broad tail. We measure a slightly reddish colour with a g′–r′ colour index of 0.66 ± 0.01 mag, compatible with Solar System comets. -
Gemini Observations of Active Asteroid 354P/LINEAR (2010 A2)
Gemini Observations of Active Asteroid 354P/LINEAR (2010 A2) Yoonyoung Kim, Masateru Ishiguro Seoul National University (Korea) Science & Evolution of Gemini Observatory 2018 Fisherman’s Wharf, San Francisco Contents • Overview • Active asteroids resulting from impacts • The case of 354P/LINEAR (2010 A2) • Concluding remark Overview “Small Solar System bodies are primitive, but...” Solar System Formation “Snow line” Credit: Univ. of Hawaii Primitive small bodies Kuiper Belt ~30-55 AU Oort Cloud ~104-105 AU Yeomans 2000 Primitive small bodies (easy to observe) are comets and asteroids Kuiper Belt ~30-55 AU Oort Cloud ~104-105 AU Yeomans 2000 but, primitive small bodies also evolved... by solar radiative heating by impacts NASA/JPL/Univ. of Maryland but, primitive small bodies also evolved... by solar radiative heating by impacts NASA/JPL/Univ. of Maryland Purpose of this study • We aim to figure out one of the major evolutionary processes in the Solar System (impacts) through observational studies of • Active asteroids resulting from impacts • The case of 354P/LINEAR (2010 A2) Comets Active Asteroids Active asteroids Dormant Comets Asteroids resulting from impacts : The case of 354P/LINEAR (2010 A2) Kim, Y., Ishiguro, M., et al. 2017, AJ Kim, Y., Ishiguro, M., & Lee, M. G. 2017, ApJL Background “Evidences of past impacts” Credit: D. Jewitt The case of (596) Scheila Ishiguro+2011 The case of 354P/2010 A2 Jewitt+2011 The case of 354P/2010 A2 The case of 354P/2010 A2 Previous modelings (Jewitt+10,13; Snodgrass+10; Hainaut+12; Agarwal+13; Kleyna+13) Jewitt+2013 Kleyna+2013 Observation 2010 Model Observation Agarwal+2013 Obs. -
Molecular Reconnaissance of the $\Beta $ Pictoris Gas Disk with The
Draft version January 15, 2018 Typeset using LATEX twocolumn style in AASTeX61 MOLECULAR RECONNAISSANCE OF THE β PICTORIS GAS DISK WITH THE SMA: A LOW HCN/(CO+CO2) OUTGASSING RATIO AND PREDICTIONS FOR FUTURE SURVEYS L. Matra`,1, ∗ D. J. Wilner,1 K. I. Oberg,¨ 1 S. M. Andrews,1 R. A. Loomis,1 M. C. Wyatt,2 and W. R. F. Dent3 1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 2Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 3ALMA Santiago Central Offices, Alonso de Cordova 3107, Vitacura, Santiago, Chile (Received 2017 September 13; Revised 2017 December 20; Accepted 2017 December 24) ABSTRACT The exocometary origin of CO gas has been confirmed in several extrasolar Kuiper belts, with CO ice abundances consistent with Solar System comets. We here present a molecular survey of the β Pictoris belt with the Submillimeter + + Array (SMA), reporting upper limits for CN, HCN, HCO ,N2H and H2CO, as well as for H2S, CH3OH, SiO and DCN from archival ALMA data. Non-detections can be attributed to rapid molecular photodissociation due to the A- star's strong UV flux. CN is the longest-lasting and most easily detectable molecule after CO in this environment. We update our NLTE excitation model to include UV fluorescence, finding it plays a key role in CO and CN excitation, and use it to turn the SMA CN/CO flux ratio constraint into an upper limit of < 2:5% on the HCN/(CO+CO2) ratio of outgassing rates. This value is consistent with, but at the low end of, the broad range observed in Solar System comets. -
Comet Interceptor: a Mission to an Ancient World
EPSC Abstracts Vol. 14, EPSC2020-574, 2020 https://doi.org/10.5194/epsc2020-574 Europlanet Science Congress 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Comet Interceptor: A mission to an ancient world Cecilia Tubiana1, Geraint Jones2,3, Colin Snodgrass4, and the the Comet Interceptor Team* 1Max Planck Institute for Solar System Research, Goettingen, Germany ([email protected]) 2Mullard Space Science Laboratory, University College London, Surrey, UK 3The Centre for Planetary Sciences at UCL/Birkbeck, London, UK 4Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh *A full list of authors appears at the end of the abstract Comets are the most pristine objects in our Solar System. Having spent most of their life at large distance from the Sun, where they remained mostly unaffected by solar radiation, comets are the most unaltered remnants from the era of planet formation. In June 2019, a multi-spacecraft project – Comet Interceptor – was selected by the European Space Agency (ESA) as its next planetary mission, and the first in its new class of Fast (F) projects [1]. The mission’s primary science goal is to characterise, for the first time, a long-period comet – preferably one which is dynamically new – or an interstellar object. An encounter with a comet approaching the Sun for the first time will provide valuable data to complement that from all previous comet missions: the surface of such an object would be being heated to temperatures above the its constituent ices’ sublimation point for the first time since its formation.