Outer Planets: the Ice Giants
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Exomoon Habitability Constrained by Illumination and Tidal Heating
submitted to Astrobiology: April 6, 2012 accepted by Astrobiology: September 8, 2012 published in Astrobiology: January 24, 2013 this updated draft: October 30, 2013 doi:10.1089/ast.2012.0859 Exomoon habitability constrained by illumination and tidal heating René HellerI , Rory BarnesII,III I Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany, [email protected] II Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195, [email protected] III NASA Astrobiology Institute – Virtual Planetary Laboratory Lead Team, USA Abstract The detection of moons orbiting extrasolar planets (“exomoons”) has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary “habitable edge”. We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons. -
Geological Timeline
Geological Timeline In this pack you will find information and activities to help your class grasp the concept of geological time, just how old our planet is, and just how young we, as a species, are. Planet Earth is 4,600 million years old. We all know this is very old indeed, but big numbers like this are always difficult to get your head around. The activities in this pack will help your class to make visual representations of the age of the Earth to help them get to grips with the timescales involved. Important EvEnts In thE Earth’s hIstory 4600 mya (million years ago) – Planet Earth formed. Dust left over from the birth of the sun clumped together to form planet Earth. The other planets in our solar system were also formed in this way at about the same time. 4500 mya – Earth’s core and crust formed. Dense metals sank to the centre of the Earth and formed the core, while the outside layer cooled and solidified to form the Earth’s crust. 4400 mya – The Earth’s first oceans formed. Water vapour was released into the Earth’s atmosphere by volcanism. It then cooled, fell back down as rain, and formed the Earth’s first oceans. Some water may also have been brought to Earth by comets and asteroids. 3850 mya – The first life appeared on Earth. It was very simple single-celled organisms. Exactly how life first arose is a mystery. 1500 mya – Oxygen began to accumulate in the Earth’s atmosphere. Oxygen is made by cyanobacteria (blue-green algae) as a product of photosynthesis. -
Giant Planet Effects on Terrestrial Planet Formation and System Architecture
MNRAS 485, 541–549 (2019) doi:10.1093/mnras/stz385 Advance Access publication 2019 February 8 Giant planet effects on terrestrial planet formation and system architecture 1‹ 2 2,3 1 Anna C. Childs, Elisa Quintana, Thomas Barclay and Jason H. Steffen Downloaded from https://academic.oup.com/mnras/article-abstract/485/1/541/5309996 by NASA Goddard Space Flight Ctr user on 15 April 2020 1Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154, USA 2NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA 3University of Maryland, Baltimore County, 1000 Hilltop Cir, Baltimore, MD 21250, USA Accepted 2019 February 4. Received 2019 January 16; in original form 2018 July 6 ABSTRACT Using an updated collision model, we conduct a suite of high-resolution N-body integrations to probe the relationship between giant planet mass and terrestrial planet formation and system architecture. We vary the mass of the planets that reside at Jupiter’s and Saturn’s orbit and examine the effects on the interior terrestrial system. We find that massive giant planets are more likely to eject material from the outer edge of the terrestrial disc and produce terrestrial planets that are on smaller, more circular orbits. We do not find a strong correlation between exterior giant planet mass and the number of Earth analogues (analogous in mass and semimajor axis) produced in the system. These results allow us to make predictions on the nature of terrestrial planets orbiting distant Sun-like star systems that harbour giant planet companions on long orbits – systems that will be a priority for NASA’s upcoming Wide-Field Infrared Survey Telescope (WFIRST) mission. -
Activity 16: Planets and Their Features Mercury Mercury Is an Extreme Planet
Activity 16: Planets And Their Features Mercury Mercury.is.an.extreme.planet..It.is.the.fastest.of.all.the.planets..It.is.one.of.the.hottest. planets,.and.it.is.also.one.of.the.coldest!.It.may.be.the.site.of.the.largest.crash.in.the. history.of.the.solar.system..Mercury.may.also.have.the.strangest.view.of.the.sun.in.the. whole.universe! Mercury.zooms.around.the.sun.at.a.speed.of.48.kilometres.per.second,.or.half.as.fast. again.as.the.Earth.travels. At.certain.times.and.places,.Mercury’s.surface.temperature.can.rise.to.twice.the. temperature.inside.an.oven.when.you.are.baking.a.cake..On.the.other.hand,.in.the. shadow.of.its.North.Pole.craters,.Mercury.has.ice.like.our.North.Pole.does. Since.Mercury.is.so.close.to.the.sun,.we.have.never.been.able.to.see.it.in.any.detail..Even. with.the.most.powerful.telescope,.Mercury.looks.like.a.blurry.white.ball..It.wasn’t.until.1974. that.we.really.began.to.learn.about.Mercury..In.1974.and.1975,.Mariner.10.flew.by.Mercury.three.times.and.sent.back. about.12,000.images. These.pictures.combined.to.give.a.map.of.about.45%.of.Mercury’s.surface,.and.what.they.show.us.is.a.planet.covered. with.craters,.much.like.our.moon..Mercury’s.largest.land.feature.is.the.Caloris.Basin,.a.crater.formed.by.a.collision.with.a. meteorite.long.ago..The.size.of.the.Caloris.Basin,.about.1350.kilometres.in.diameter,.suggests.that.this.may.have.been. -
The Solar System Cause Impact Craters
ASTRONOMY 161 Introduction to Solar System Astronomy Class 12 Solar System Survey Monday, February 5 Key Concepts (1) The terrestrial planets are made primarily of rock and metal. (2) The Jovian planets are made primarily of hydrogen and helium. (3) Moons (a.k.a. satellites) orbit the planets; some moons are large. (4) Asteroids, meteoroids, comets, and Kuiper Belt objects orbit the Sun. (5) Collision between objects in the Solar System cause impact craters. Family portrait of the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (Eris, Ceres, Pluto): My Very Excellent Mother Just Served Us Nine (Extra Cheese Pizzas). The Solar System: List of Ingredients Ingredient Percent of total mass Sun 99.8% Jupiter 0.1% other planets 0.05% everything else 0.05% The Sun dominates the Solar System Jupiter dominates the planets Object Mass Object Mass 1) Sun 330,000 2) Jupiter 320 10) Ganymede 0.025 3) Saturn 95 11) Titan 0.023 4) Neptune 17 12) Callisto 0.018 5) Uranus 15 13) Io 0.015 6) Earth 1.0 14) Moon 0.012 7) Venus 0.82 15) Europa 0.008 8) Mars 0.11 16) Triton 0.004 9) Mercury 0.055 17) Pluto 0.002 A few words about the Sun. The Sun is a large sphere of gas (mostly H, He – hydrogen and helium). The Sun shines because it is hot (T = 5,800 K). The Sun remains hot because it is powered by fusion of hydrogen to helium (H-bomb). (1) The terrestrial planets are made primarily of rock and metal. -
Alien Moons Could Bake Dry from Young Gas Giants' Hot Glow 10 March 2014, by Adam Hadhazy
Alien moons could bake dry from young gas giants' hot glow 10 March 2014, by Adam Hadhazy scenarios because they orbit another body besides their star. A new paper by Heller and his colleague Rory Barnes of the University of Washington and the NASA Virtual Planetary Laboratory examines how heat emanating from a freshly formed exoplanet, coupled with irradiation from the solar system's star, can roast the planet's moons. Before the planet cools off sufficiently, its close-orbiting moons could lose all their water, leaving them bone-dry and barren. "An exomoon's habitability is of course constrained by its location in the stellar habitable zone, but it also has a second heat source—its host planet—that has to be accounted for," said Heller, whose paper An Earthlike moon orbiting a gas giant host planet. has been accepted for publication in The Credit: NASA International Journal of Astrobiology. "With regard to this second source, our study shows that at close range, the illumination from young and hot giant planets can render their moons uninhabitable." When we think of where else life might exist in the universe, we tend to focus on planets. But on a Researchers believe moons could serve as suitable grander cosmic scale, moons could prove the more abodes for life just as well as planets. Even moons common life-friendly abode. far beyond the habitable zone, such as Jupiter's Europa and Saturn's Titan, offer tantalizing hints of A single gas giant planet in the not-too-warm, not- potential habitability thanks to the subsurface too-cold habitable zone around its star—where ocean in the former and the intriguing organic Earth and Mars correspondingly reside—could host chemistry of the latter. -
Constructing the Solar System: a Smashing Success
Constructing the Solar System: A Smashing Success A Star is Born Thomas M. Davison Department of the Geophysical Sciences Compton Lecture Series October 6, 2012 T. M. Davison Constructing the Solar System Compton Lectures { Autumn 2012 1 Today's lecture 1 An overview of the Compton Lecture Series 2 A tour of the Solar System 3 Physical properties of the Solar System What can they tell us about the Solar System's formation? 4 How was our star born? The nebula hypothesis of star formation Images courtesy of NASA T. M. Davison Constructing the Solar System Compton Lectures { Autumn 2012 2 Part 1: Introduction to the lecture series Image courtesy of NASA T. M. Davison Constructing the Solar System Compton Lectures { Autumn 2012 3 Constructing the Solar System ... How did the Sun, the planets and the asteroids form? What were their histories like? One process dominates throughout Solar System history: Collisions Growth of asteroids and planets Formation of the Moon Extinction of the dinosaurs After such a violent history, we now have a habitable planet Which you could call: ... A Smashing Success! Images Courtesy of NASA T. M. Davison Constructing the Solar System Compton Lectures { Autumn 2012 4 My day job: Making an impact Computer simulations of collisions between planetesimals Simulations by T. Davison T. M. Davison Constructing the Solar System Compton Lectures { Autumn 2012 5 Compton Lecture Series Schedule 1 10/06/12 A Star is Born 2 10/13/12* Making Planetesimals: the building blocks of planets 3 10/20/12* Guest Lecturer: Mac Cathles 4 10/27/12 Asteroids, Comets and Meteorites: 10/27/12 our eyes in the early Solar System 5 11/03/12 Building the Planets 6 11/10/12 When Asteroids Collide 7 11/17/12 Making Things Hot: The thermal effects of collisions 11/24/12 No lecture: Thanksgiving weekend 8 12/01/12 Constructing the Moon 12/08/12 No lecture: Physics with a Bang! 9 12/15/12 Impact Earth: Chicxulub and other terrestrial impacts T. -
Discovery of a Low-Mass Companion to a Metal-Rich F Star with the Marvels Pilot Project
The Astrophysical Journal, 718:1186–1199, 2010 August 1 doi:10.1088/0004-637X/718/2/1186 C 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. DISCOVERY OF A LOW-MASS COMPANION TO A METAL-RICH F STAR WITH THE MARVELS PILOT PROJECT Scott W. Fleming1,JianGe1, Suvrath Mahadevan1,2,3, Brian Lee1, Jason D. Eastman4, Robert J. Siverd4, B. Scott Gaudi4, Andrzej Niedzielski5, Thirupathi Sivarani6, Keivan G. Stassun7,8, Alex Wolszczan2,3, Rory Barnes9, Bruce Gary7, Duy Cuong Nguyen1, Robert C. Morehead1, Xiaoke Wan1, Bo Zhao1, Jian Liu1, Pengcheng Guo1, Stephen R. Kane1,10, Julian C. van Eyken1,10, Nathan M. De Lee1, Justin R. Crepp1,11, Alaina C. Shelden1,12, Chris Laws9, John P. Wisniewski9, Donald P. Schneider2,3, Joshua Pepper7, Stephanie A. Snedden12, Kaike Pan12, Dmitry Bizyaev12, Howard Brewington12, Olena Malanushenko12, Viktor Malanushenko12, Daniel Oravetz12, Audrey Simmons12, and Shannon Watters12,13 1 Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 326711-2055, USA; scfl[email protected]fl.edu 2 Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802, USA 3 Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802, USA 4 Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA 5 Torun´ Center for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, 87-100, Torun,´ Poland 6 Indian Institute of Astrophysics, Bangalore 560034, India 7 Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA 8 Department of Physics, Fisk University, 1000 17th Ave. -
Mixing of the Asteroid Belt Due to the Formation of the Giant Planets
Accretion: Building New Worlds (2017) 2027.pdf MIXING OF THE ASTEROID BELT DUE TO THE FORMATION OF THE GIANT PLANETS. K. A. Kretke1, W. F. Bottke2,3, H. F. Levison2,3, and D. A. Kring4,5, 1SSERVI NPP Fellow ([email protected]), 2Southwest Research Institute, 1050 Walnut St, Suite 300, Boulder, CO 80302, USA, 3ISET, NASA-SSERVI, 4LPI, 3600 Bay Area Blvd, Houston, TX 77058, USA 5CLSE, NASA-SSERVI. Introduction: The asteroid belt is observed to be a evolution of a solar system forming under these condi- mixture of objects with different compositions, with tions. LIPAD is based upon the N-Body integrator volatile-poor asteroids (mostly S-complex) dominant in SWIFT [10] but uses novel algorithms to statistically the inner asteroid belt while volatile-rich (mostly C- follow bodies that are too small and numerous to be han- complex) asteroids dominate the outer asteroid belt. dled in a traditional N-body integrator. This allows us to While this general compositional stratification was orig- model how our system may have evolved starting from inally thought to be an indicator of the primordial tem- pebbles and planetesimals all the way to a mature plan- perature gradient in the protoplanetary disk, there is etary system. growing evidence that that meteorites believed to origi- To test the effect of giant planet formation in the as- nate from those different types of asteroids appear to teroid belt we placed a population planetesimals in outer come from very distinct reservoirs, with distinct iso- Solar System and allow them to accrete pebbles. To topic and elemental signatures [1,2,3]. -
Simon Porter , Will Grundy
Post-Capture Evolution of Potentially Habitable Exomoons Simon Porter1,2, Will Grundy1 1Lowell Observatory, Flagstaff, Arizona 2School of Earth and Space Exploration, Arizona State University [email protected] and spin vector were initially pointed at random di- Table 1: Relative fraction of end states for fully Abstract !"# $%& " '(" !"# $%& # '(# rections on the sky. The exoplanets had a ran- evolved exomoon systems dom obliquity < 5 deg and was at a stellarcentric The satellites of extrasolar planets (exomoons) Star Planet Moon Survived Retrograde Separated Impacted distance such that the equilibrium temperature was have been recently proposed as astrobiological tar- Earth 43% 52% 21% 35% equal to Earth. The simulations were run until they Jupiter Mars 44% 45% 18% 37% gets. Triton has been proposed to have been cap- 5 either reached an eccentricity below 10 or the pe- Titan 42% 47% 21% 36% tured through a momentum-exchange reaction [1], − Sun Earth 52% 44% 17% 30% riapse went below the Roche limit (impact) or the and it is possible that a similar event could allow Neptune Mars 44% 45% 18% 36% apoapse exceeded the Hill radius. Stars used were Titan 45% 47% 19% 35% a giant planet to capture a formerly binary terres- Earth 65% 47% 3% 31% the Sun (G2), a main-sequence F0 (1.7 MSun), trial planet or planetesimal. We therefore attempt to Jupiter Mars 59% 46% 4% 35% and a main-sequence M0 (0.47 MSun). Exoplan- Titan 61% 48% 3% 34% model the dynamical evolution of a terrestrial planet !"# $%& " !"# $%& " ' F0 ets used had the mass of either Jupiter or Neptune, Earth 77% 44% 4% 18% captured into orbit around a giant planet in the hab- and exomoons with the mass of Earth, Mars, and Neptune Mars 67% 44% 4% 28% itable zone of a star. -
Arthur C. Clarke and Cs Lewis on Moral
Kaufmann, “Riddles in Space” LATCH, Vol. 6, 2013, pp. 55-74 RIDDLES IN SPACE: ARTHUR C. CLARKE AND C.S. LEWIS ON MORAL EXTRAPOLATION By U. Milo Kaufmann University of Illinois, Urbana-Champagne (emeritus) With many matters of prediction science fiction has proved to be prescient. When the genre has been too accurate, as with sundry technological innovations such as the submarine, the prophetic works have tended to lose their interest for the general reader. With another kind of prediction, however, in which utterly novel situations or agents are presented, it is common for perennial moral mysteries to be engaged and, with historic actualization delayed for whatever reasons, it is difficult to be certain just how plausible the projections are. It is not too early to provide some simple definitions and distinctions which will help us in discussing several moral riddles posed when SF masters such as C. S. Lewis and Arthur C. Clarke follow their imaginations into space. 55 Kaufmann, “Riddles in Space” LATCH, Vol. 6, 2013, pp. 55-74 Any one-time student of plane geometry or or statistical graphing will recall that extrapolation is projecting points beyond the line defined by given points. In logic, extrapolation has an analogue in the process of induction, or inducing a general truth from multiple examples. In a legal system we have what is simply described as case law or the resolution of the new challenge by way of precedents. In casuistry, or the disciplines of resolving moral questions, we have the innumerable old volumes common to Scholastic and other writers, dealing in cases of conscience. -
Explore Jupiter's Family Secrets: JUMP to JUPITER
~ LPI EDUCATION/PUBLIC ENGAGEMENT SCIENCE ACTIVITIES ~ Explore Jupiter’s Family Secrets: JUMP TO JUPITER OVERVIEW — Participants jump through a course from the grapefruit-sized “Sun,” past poppy-seed-sized “Earth,” and on to marble-sized “Jupiter” — and beyond! By counting the jumps needed to reach each object, children experience first-hand the vast scale of our solar system. WHAT’S THE POINT? The solar system is a family of eight planets, an asteroid belt, several dwarf planets, and numerous small bodies such as comets in orbit around the Sun. The four inner terrestrial planets are small compared to the four outer gas giants. The distance between planetary orbits is large compared to their sizes. Models can be used to answer questions about the solar system. MATERIALS — Facility needs: ☐ A large area, such as a long hallway, a sidewalk that extends for several blocks, or a football field (see Preparation section for setup options) ☐ A variety of memorable objects used to represent the Sun and planets, such as (use Jump to Jupiter: Planet Sizes and Distances to identify an appropriately-sized substitutes as needed): ☐ 1 (4 inch) grapefruit ☐ 2 (½ inch) marbles ☐ 2 peppercorns ☐ 2 poppy seeds ☐ 3 pepper flakes ☐ 1 pinch of fine sand or dust ☐ 1 set of solar system object markers created (preferably in color) from: • 1 set of Jump to Jupiter: Planet Information Sheets OR Credit: Enid Costley, Library of Virginia • Posters created by the participants OR • Optional: 1 set of Our Solar System lithographs (NASA educational product number LS-2013-07-003-HQ):