Active Asteroids

Total Page：16

File Type：pdf, Size：1020Kb

Active Asteroids Active asteroids are objects that exhibit comet-like activity but are dynamically asteroidal. They include main- belt comets, whose activity is believed to be driven by the sublimation of volatile ice, like in classical comets, and disrupted asteroids, whose activity is believed to be pro- duced by other mechanisms, such as impacts or rotation- al destabilization. The discovery that main-belt comets still contain suffi- cient near-surface ice to drive cometary activity is sur- prising, given their apparently stable orbits in the main Image Credit: Henry Hsieh/ Pan-STARRS1 Science Consortium/IFA asteroid belt in the warm inner solar system. Main-belt comets have also drawn considerable atten- This image of main-belt comet tion for their astrobiological significance, as they offer an 288P, is the first of many active opportunity for probing the ice content of the inner solar system, which is important for testing and constraining asteroids discovered by the Pan- models of terrestrial planet formation and the primordial STARRS1 survey. LSST should delivery of water to the Earth, which then sets the stage for the rise of life. Meanwhile, disrupted asteroids offer discover many more, providing exciting in situ opportunities to study impact and rotation- exciting opportunities for al disruption processes that have previously only been studied in the lab or using computer modeling. advancing our understanding of these intriguing objects. The discovery of more active asteroids is a high priority for Solar System scientists. Less than 30 active asteroids are currently known, most of them discovered by currently operating all-sky surveys at a rate of a few per year. With its larger mirror and increased sensitivity compared to current surveys, LSST may increase this discovery rate by See more at www.lsstsssc.org 10-fold or more, enabling a far broader range of research into these mysterious objects than is currently possible. Photo Credit: PanSTARRS C/2017 S3 Michael Jager.

Copy Link

Recommended publications

Origin and Evolution of Trojan Asteroids 725
Marzari et al.: Origin and Evolution of Trojan Asteroids 725 Origin and Evolution of Trojan Asteroids F. Marzari University of Padova, Italy H. Scholl Observatoire de Nice, France C. Murray University of London, England C. Lagerkvist Uppsala Astronomical Observatory, Sweden The regions around the L4 and L5 Lagrangian points of Jupiter are populated by two large swarms of asteroids called the Trojans. They may be as numerous as the main-belt asteroids and their dynamics is peculiar, involving a 1:1 resonance with Jupiter. Their origin probably dates back to the formation of Jupiter: the Trojan precursors were planetesimals orbiting close to the growing planet. Different mechanisms, including the mass growth of Jupiter, collisional diffusion, and gas drag friction, contributed to the capture of planetesimals in stable Trojan orbits before the final dispersal. The subsequent evolution of Trojan asteroids is the outcome of the joint action of different physical processes involving dynamical diffusion and excitation and collisional evolution. As a result, the present population is possibly different in both orbital and size distribution from the primordial one. No other significant population of Trojan aster- oids have been found so far around other planets, apart from six Trojans of Mars, whose origin and evolution are probably very different from the Trojans of Jupiter. 1. INTRODUCTION originate from the collisional disruption and subsequent reaccumulation of larger primordial bodies. As of May 2001, about 1000 asteroids had been classi- A basic understanding of why asteroids can cluster in fied as Jupiter Trojans (http://cfa-www.harvard.edu/cfa/ps/ the orbit of Jupiter was developed more than a century lists/JupiterTrojans.html), some of which had only been ob- before the first Trojan asteroid was discovered.
[Show full text]
The Orbital Distribution of Near-Earth Objects Inside Earthâ€™S Orbit
Icarus 217 (2012) 355–366 Contents lists available at SciVerse ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus The orbital distribution of Near-Earth Objects inside Earth’s orbit ⇑ Sarah Greenstreet a, , Henry Ngo a,b, Brett Gladman a a Department of Physics & Astronomy, 6224 Agricultural Road, University of British Columbia, Vancouver, British Columbia, Canada b Department of Physics, Engineering Physics, and Astronomy, 99 University Avenue, Queen’s University, Kingston, Ontario, Canada article info abstract Article history: Canada’s Near-Earth Object Surveillance Satellite (NEOSSat), set to launch in early 2012, will search for Received 17 August 2011 and track Near-Earth Objects (NEOs), tuning its search to best detect objects with a < 1.0 AU. In order Revised 8 November 2011 to construct an optimal pointing strategy for NEOSSat, we needed more detailed information in the Accepted 9 November 2011 a < 1.0 AU region than the best current model (Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.M., Levison, Available online 28 November 2011 H.F., Michel, P., Metcalfe, T.S. [2002]. Icarus 156, 399–433) provides. We present here the NEOSSat-1.0 NEO orbital distribution model with larger statistics that permit ﬁner resolution and less uncertainty, Keywords: especially in the a < 1.0 AU region. We ﬁnd that Amors = 30.1 ± 0.8%, Apollos = 63.3 ± 0.4%, Atens = Near-Earth Objects 5.0 ± 0.3%, Atiras (0.718 < Q < 0.983 AU) = 1.38 ± 0.04%, and Vatiras (0.307 < Q < 0.718 AU) = 0.22 ± 0.03% Celestial mechanics Impact processes of the steady-state NEO population.
[Show full text]
The Physical Characterization of the Potentially-‐Hazardous
The Physical Characterization of the Potentially-Hazardous Asteroid 2004 BL86: A Fragment of a Differentiated Asteroid Vishnu Reddy1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Email: [email protected] Bruce L. Gary Hereford Arizona Observatory, Hereford, AZ 85615, USA Juan A. Sanchez1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Driss Takir1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Cristina A. Thomas1 NASA Goddard Spaceflight Center, Greenbelt, MD 20771, USA Paul S. Hardersen1 Department of Space Studies, University of North Dakota, Grand Forks, ND 58202, USA Yenal Ogmen Green Island Observatory, Geçitkale, Mağusa, via Mersin 10 Turkey, North Cyprus Paul Benni Acton Sky Portal, 3 Concetta Circle, Acton, MA 01720, USA Thomas G. Kaye Raemor Vista Observatory, Sierra Vista, AZ 85650 Joao Gregorio Atalaia Group, Crow Observatory (Portalegre) Travessa da Cidreira, 2 rc D, 2645- 039 Alcabideche, Portugal Joe Garlitz 1155 Hartford St., Elgin, OR 97827, USA David Polishook1 Weizmann Institute of Science, Herzl Street 234, Rehovot, 7610001, Israel Lucille Le Corre1 Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, USA Andreas Nathues Max-Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany 1Visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NNX-08AE38A with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. Pages: 27 Figures: 8 Tables: 4 Proposed Running Head: 2004 BL86: Fragment of Vesta Editorial correspondence to: Vishnu Reddy Planetary Science Institute 1700 East Fort Lowell Road, Suite 106 Tucson 85719 (808) 342-8932 (voice) [email protected] Abstract The physical characterization of potentially hazardous asteroids (PHAs) is important for impact hazard assessment and evaluating mitigation options.
[Show full text]
Solar System Planet and Dwarf Planet Fact Sheet
Solar System Planet and Dwarf Planet Fact Sheet The planets and dwarf planets are listed in their order from the Sun. Mercury The smallest planet in the Solar System. The closest planet to the Sun. Revolves the fastest around the Sun. It is 1,000 degrees Fahrenheit hotter on its daytime side than on its night time side. Venus The hottest planet. Average temperature: 864 F. Hotter than your oven at home. It is covered in clouds of sulfuric acid. It rains sulfuric acid on Venus which comes down as virga and does not reach the surface of the planet. Its atmosphere is mostly carbon dioxide (CO2). It has thousands of volcanoes. Most are dormant. But some might be active. Scientists are not sure. It rotates around its axis slower than it revolves around the Sun. That means that its day is longer than its year! This rotation is the slowest in the Solar System. Earth Lots of water! Mountains! Active volcanoes! Hurricanes! Earthquakes! Life! Us! Mars It is sometimes called the "red planet" because it is covered in iron oxide -- a substance that is the same as rust on our planet. It has the highest volcano -- Olympus Mons -- in the Solar System. It is not an active volcano. It has a canyon -- Valles Marineris -- that is as wide as the United States. It once had rivers, lakes and oceans of water. Scientists are trying to find out what happened to all this water and if there ever was (or still is!) life on Mars. It sometimes has dust storms that cover the entire planet.
[Show full text]
19. Near-Earth Objects Chelyabinsk Meteor: 2013 ~0.5 Megaton Airburst ~1500 People Injured
Astronomy 241: Foundations of Astrophysics I 19. Near-Earth Objects Chelyabinsk Meteor: 2013 ~0.5 megaton airburst ~1500 people injured (C) Don Davis Asteroids 101 — B612 Foundation Great Daylight Fireball: 1972 Earthgrazer: The Great Daylight Fireball of 1972 Tunguska Meteor: 1908 Asteroid or comet: D ~ 40 m ~10 megaton airburst ~40 km destruction radius The Tunguska Impact Tunguska: The Largest Recent Impact Event Barringer Crater: ~50 ky BP M-type asteroid: D ~ 50 m ~10 megaton impact 1.2 km crater diameter Meteor Crater — Wikipedia Chicxulub Crater: ~65 My BP Asteroid: D ~ 10 km 180 km crater diameter Chicxulub Crater— Wikipedia Comets and Meteor Showers Comets shed dust and debris which slowly spread out as they move along the comet’s orbit. If the Earth encounters one of these trails, we get a Breakup of a Comet meteor shower. Meteor Stream Perseid Meteor Shower Raining Perseids Major Meteor Showers Forty Thousand Meteor Origins Across the Sky Known Potentially-Hazardous Objects Near-Earth object — Wikipedia Near-Earth object — Wikipedia Origin of Near-Earth Objects (NEOs) ! WHAM Mars Some fragments wind up on orbits which are resonant with Jupiter. Their orbits grow more elliptical, ﬁnally entering the inner solar system. Wikipedia: Asteroid belt Asteroid Families Many asteroids are members of families; they have similar orbits and compositions (indicated by colors). Asteroid Belt Populations Inner belt asteroids (left) and families (right). Origin of Key Stages in the Evolution of the Asteroid Vesta Processed Family Members Crust Surface Magnesium-Sliicate Lavas Meteorites Mantle (Olivine) Iron-Nickle Core Stony Irons? As smaller bodies in the early Solar System Heavier elements sink to the Occasional impacts with other bodies fall together, the asteroid agglomerates.
[Show full text]
Ceres Is the Largest Object in the Asteroid Belt, Which Lies Mainly
Dactyl, the moon of Ida, is shown below in a close-up and at its true size relative to Ida. Dactyl was the Ceres and the Asteroid Belt ﬁrst asteroid moon to be discovered. Ceres is the largest object in the The best photos of Ceres (below left) and Vesta (below right) as As of 2008, only the asteroid belt, which lies mainly of 2008, from the Hubble Space Telescope (courtesy NASA/ESA) handful of asteroids between Mars and Jupiter. shown here have had Ida and Dactyl, from NASA’s Galileo Asteroids are made of various their pictures taken combinations of rocks, metals and by spacecraft ﬂying carbon compounds that have past them. If you’re Steins, Ceres is much smaller than the Moon, which is shown below reading this panel from ESA’s Rosetta Eros, from NEAR never been captured by any after 2011, you’ve planet’s gravity. Asteroids have on the same scale as Ceres and Vesta above. Nonetheless, Shoemaker Ceres is sometimes referred to as a dwarf planet, hopefully seen better (NASA/JHUAPL) not changed much for billions of along with Pluto and a growing list of other objects. photos of Vesta, the years, making them important third-largest object in records of the formation of the the asteroid belt, solar system. The solar system taken by the Mathilde, from contains millions of asteroids Dawn spacecraft. And if you’re reading NEAR Shoemaker ranging down to the size of large (NASA/JHUAPL) this panel after 2015, boulders, as well as smaller hopefully there are objects called meteoroids.
[Show full text]
The Minor Planet Bulletin, It Is a Pleasure to Announce the Appointment of Brian D
THE MINOR PLANET BULLETIN OF THE MINOR PLANETS SECTION OF THE BULLETIN ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS VOLUME 33, NUMBER 1, A.D. 2006 JANUARY-MARCH 1. LIGHTCURVE AND ROTATION PERIOD Observatory (Observatory code 926) near Nogales, Arizona. The DETERMINATION FOR MINOR PLANET 4006 SANDLER observatory is located at an altitude of 1312 meters and features a 0.81 m F7 Ritchey-Chrétien telescope and a SITe 1024 x 1024 x Matthew T. Vonk 24 micron CCD. Observations were conducted on (UT dates) Daniel J. Kopchinski January 29, February 7, 8, 2005. A total of 37 unfiltered images Amanda R. Pittman with exposure times of 120 seconds were analyzed using Canopus. Stephen Taubel The lightcurve, shown in the figure below, indicates a period of Department of Physics 3.40 ± 0.01 hours and an amplitude of 0.16 magnitude. University of Wisconsin – River Falls 410 South Third Street Acknowledgements River Falls, WI 54022 [email protected] Thanks to Michael Schwartz and Paulo Halvorcem for their great work at Tenagra Observatory. (Received: 25 July) References Minor planet 4006 Sandler was observed during January Schmadel, L. D. (1999). Dictionary of Minor Planet Names. and February of 2005. The synodic period was Springer: Berlin, Germany. 4th Edition. measured and determined to be 3.40 ± 0.01 hours with an amplitude of 0.16 magnitude. Warner, B. D. and Alan Harris, A. (2004) “Potential Lightcurve Targets 2005 January – March”, www.minorplanetobserver.com/ astlc/targets_1q_2005.htm Minor planet 4006 Sandler was discovered by the Russian astronomer Tamara Mikhailovna Smirnova in 1972. (Schmadel, 1999) It orbits the sun with an orbit that varies between 2.058 AU and 2.975 AU which locates it in the heart of the main asteroid belt.
[Show full text]
LESSON PLAN Teacher: Date: Prior to “Give Me Space!” Performance
LESSON PLAN Teacher: Date: Prior to “Give Me Space!” performance Grade Level/Subject: 4th/Math & Science Co-Teaching Model Utilized: Central Focus: To only serve as a predecessor classroom activity accompaniment for students meant to experience the performance of “GIVE ME SPACE!” During the performance, all students will intentionally hear musical compositions written for each of the 5 – IAU established dwarf planets and acknowledge as fourth graders their previously conducted study where constructing 3-D volumetric scaled models indicate their relative sizes to one another, positioning locations in- and outside of our solar system, while also learning of their reasons of qualification as dwarf status and then additional physical properties. Standards: Math 4.NF.B.3. Understand a fraction a/b with a>1 as a sum of fractions 1/b. 4.NF.B.4. Apply and extend previous understandings of multiplication as repeated addition to multiply a whole number by a fraction. 4.NF.B.5. Express a fraction with denominator 10 as an equivalent fraction with denominator 100, and use this technique to add two fractions with respective denominators 10 and 100. 4.MD.A.1. Measure and estimate to determine relative sizes of measurement units within a single system of measurement involving length, liquid volume, and mass/weight of objected using customary and metric units. 4.MD.B.4 Make a line plot to display a data set of measurements in fractions of a unit. Use operations on fractions for this grade to solve problems involving information presented in line plots. Science 4.ETS2:1) Use appropriate tools and measurements to build a model.
[Show full text]
15342 (Stsci Edit Number: 0, Created: Thursday, August 2, 2018 4:42:04 PM EST) - Overview
Proposal 15342 (STScI Edit Number: 0, Created: Thursday, August 2, 2018 4:42:04 PM EST) - Overview 15342 - Active Asteroids Target of Opportunity P/2017 S5 Cycle: 25, Proposal Category: GO (Availability Mode: SUPPORTED) INVESTIGATORS Name Institution E-Mail Dr. David Jewitt (PI) (Contact) University of California - Los Angeles [email protected] Dr. Harold A. Weaver (CoI) (Contact) The Johns Hopkins University Applied Physics Labor [email protected] atory Max Mutchler (CoI) (Contact) Space Telescope Science Institute [email protected] Dr. Jessica Agarwal (CoI) (ESA Member) (Contact Max Planck Institute for Solar System Research [email protected] ) Dr. Jing Li (CoI) University of California - Los Angeles [email protected] Dr. Stephen M. Larson (CoI) University of Arizona [email protected] VISITS Visit Targets used in Visit Configurations used in Visit Orbits Used Last Orbit Planner Run OP Current with Visit? 01 (1) P2017S5 WFC3/UVIS 1 02-Aug-2018 17:42:02.0 yes 02 (1) P2017S5 WFC3/UVIS 1 02-Aug-2018 17:42:03.0 yes 2 Total Orbits Used ABSTRACT Active asteroids are a recently discovered solar system population in which diverse mechanisms generate unexpected asteroid mass loss. They are interesting scientifically because the mechanisms (rotational disruption, impact, volatile sublimation and others not yet identified) have not previously been observed in the asteroid belt. Our past work with HST has shown that high resolution is crucially important for understanding the properties of the active asteroids. Here, we seek 2 orbits of Target of Opportunity time so that we can quickly respond to a new active asteroid 1 Proposal 15342 (STScI Edit Number: 0, Created: Thursday, August 2, 2018 4:42:04 PM EST) - Overview discovery, obtain and initial assessment of its properties and rates of change, and then make an evidence-based decision about the need for requesting more time in order to understand the object.
[Show full text]
Ceres and Pluto: Dwarf Planets As a New Way of Thinking About an Old Solar System
Ceres and Pluto: Dwarf Planets as a New Way of Thinking about an Old Solar System TEACHER GUIDE BACKGROUND The decision by the International Astronomical Union (IAU) in 2006 to define the terms “planet” and “dwarf planet” has caught the attention of the public and students from grade school to graduate school. The IAU’s decision has not changed the structure of the solar system; it has merely presented a different way of classifying the bodies that make it up. Planets are the Greek word for “wanderers” that were known as lights that moved in the sky. This middle school activity, developed for NASA’s Dawn mission, utilizes a researched-based instructional strategy called direct vocabulary instruction to help students understand the new definitions of planet and dwarf planet. Many of us have grown up with an understanding that our solar system is comprised of remnants from its early formation 4.5 billion years ago, primarily: bodies such as the Sun, planets, asteroids and comets; gas and dust, as well as a large volume of space. Many school children have learned the names and locations of the planets relative to the Sun using a mnemonic such as My Very Exceptional Mother Just Sat Upon Nine Porcupines (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto). The last of these bodies to be discovered, Pluto, has recently been reclassified as a dwarf planet. Pluto’s reduced status has even resulted in a new term as we enter 2007: someone or something has been “Plutoed” if that person or thing has been downsized in its prominence.
[Show full text]
The Solar System
CHAPTER 21 LESSON 4 The Solar System Dwarf Planets and Other Objects Key Concepts • What is a dwarf planet? What do you think? Read the two statements below and decide • What are the characteristics whether you agree or disagree with them. Place an A in the Before column of comets and asteroids? if you agree with the statement or a D if you disagree. After you’ve read this lesson, reread the statements to see if you have changed your mind. • How does an impact crater form? Before Statement After 7. Asteroids and comets are mainly rock and ice. 8. A meteoroid is a meteor that strikes Earth. Define Words Skim the Dwarf Planets lesson and underline words The International Astronomical Union (IAU) defines a that you do not know. Then dwarf planet as an object that orbits a star. When a dwarf read the lesson to see if you planet formed, there was enough mass and gravity for it to can define those words. If form a sphere. A dwarf planet has objects similar in mass you cannot, look up the word orbiting nearby or crossing its orbital path. Astronomers and write its definition in the margin to use as you study. classify Pluto, Ceres, Eris, Makemake, and Haumea (how MAY ah) as dwarf planets. Pluto was once considered to be a planet, but now it has the status of a dwarf planet. Visual Check 1. Interpret Which dwarf All dwarf planets are smaller than Earth’s moon. The figure planet orbits closest to Earth? below locates Ceres, Pluto, and Eris.
[Show full text]
The Comet-Asteroid Continuum
EPSC Abstracts Vol. 7 EPSC2012-176 2012 European Planetary Science Congress 2012 EEuropeaPn PlanetarSy Science CCongress c Author(s) 2012 The Comet-Asteroid Continuum David Jewitt (1,2) (1) Department of Earth and Space Sciences, UCLA, USA (2) Department of Physics and Astronomy, UCLA, USA ([email protected]) Abstract Activity This is an overview talk to discuss solar system objects LPC & HFC JFC Active Asteroids having properties intermediate between those classi- cally associated with comets and asteroids. or or or Nearly Main Belt Comets Coma Ecliptic Isotropic Comets 1. Outline Comets TJ In the minds of many, comets and asteroids are phys- 1 2 3 4 ically, observationally and dynamically distinct, and further separated by their presumed sites of formation Dead or Damocloids Dormant Asteroids in the protoplanetary disk of the Sun. But in fact, a JFC growing number of objects are known which cannot be Coma No simply categorized as either comets or asteroids. As is usual in science, such freak objects are especially illu- minating and worthy of detailed consideration. We divide these objects into two main classes: 1) Figure 1: Classiﬁcation of comets and asteroids based dynamically comet-like objects with the physical ap- on their orbits and physical appearances. This talk will pearances of asteroids (Hartmann et al. 1987) and 2) discuss primarily bodies falling in the lower left and dynamically asteroid-like objects with the physical ap- upper right quadrants of the plot. From Jewitt (2012). pearances of comets (Hsieh and Jewitt 2006). The for- mer, sometimes called “transition objects”, are best interpreted as dead or dormant comets in which the References driving volatiles have been depleted from the upper layers by past exposure to the Sun.
[Show full text]