DOCSLIB.ORG

Discovery of Gliese 581C

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Discovery of Gliese 581C Ast 4 Lecture 23 Notes J. E. Ybarra - Sacramento State 1 Extra Solar Planets - Discovery of Gliese 581c Gliese 581c Source: ESO M dwarf stars M dwarfs are ideal stars to observe in order to find small planets • Low mass - M dwarfs are low mass stars thus it is easier to detect lower mass planets around them • Low luminosity - habital zones for M dwarfs are closer (∼ 0.1 A.U.) Gliese 581 Gliese 581 is a M dwarf star. • Low Activity: Gl 581 has low photospheric activity which means that there will be low radial velocity noise (= better detection) • Mass ≈ 0.31 M • Luminosity ≈ 0.013 L • Has a Neptune-mass planet Gl 581b Kepler’s 1st Law of Motion Doppler Method Gl 581c Using the radial-velocity doppler method detected a second planet around Gl 581 (Udry et al. 2007) • P = 12.931 days • Wobble due to second planet V? = 3.01 m/s 2 Gl 581c - Kepler’s 3rd Law revisited Remember Modified Kepler’s 3rd Law 3 2 apl Ppl = Mtotal where P is in years and a is in A.U. Gl 581c - Kepler’s 3rd Law revisited 1 year P = 12.931 days = 0.0354 yr pl 365 days then a3 (0.0354)2 = 0.31 3.89 × 10−4 = a3 0.073 = a Using Kepler’s 3rd law we can estimate the distance from GL 581c to its parent star to be a = 0.073 A.U. Gl 581c Using the period and the semi-major axis of the orbit we can estimate the planets velocity. If we assume a circular orbit, then 2πa v = pl P 1.5 × 1011 m a = 0.073 A.U. = 1.1 × 1010 m 1 A.U. 3.15 × 107 s P = 0.0354 yr = 1.12 × 106 s 1 yr Gl 581c 2π(1.1 × 1010 m) v = = 6.1 × 104 m/s pl 1.12 × 106 s 3 Gl 581c Kepler’s 1st law states that the star and the planet both orbit the center of mass. As a consequence, the relationship between the masses and velocities is M?V? = mplvpl then 4 (0.31M?)(3.01 m/s) = mpl(6.1 × 10 m/s) −5 and we estimate the mass of the planet to be mpl = 1.5 × 10 M = 5.0M⊕ Gl 581c From theoretical models of planet formation for planets with masses 1 to 10 M⊕ (Valencia et al. 2006) the relationship between radius and mass is 0.267−0.272 rpl ∝ mpl Using this model we can estimate that the radius of this planet is 1.5 R⊕ Gl 581c The acceleration due to gravity on the surface of Earth is GM⊕ 2 = g R⊕ Then for Gl 581c with rpl = 1.5R⊕ and mpl = 5M⊕ G(5M⊕) GM⊕ 2 = 2.2 2 = 2.2g (1.5R⊕) R⊕ At the surface of the planet the force of gravity is about twice that of Earth. References • Udry, S., et al. 2007, A&A preprint (http://obswww.unige.ch/∼udry/udry preprint.pdf) • Valencia, D., OConnell, R. J., & Sasselov, D. 2006, Icarus, 181, 545 4.
Load more

Recommended publications
  • Book Review1.Fm
    Meteoritics & Planetary Science 42, Nr 9, 1695–1696 (2007) http://meteoritics.org Book Review Protostars and planets V, edited by Reipurth B, Jewitt D., and Keil K. Tucson, Arizona: The University of Arizona Press, 2007, 1024 p., cloth (ISBN 978-0-8165-2654-3). Some thirty years ago, planetary science and the study of star formation were different scientific fields with different practitioners who rarely interacted with one another. Planetary scientists, mostly geochemists and geophysicists, resided in geology departments whereas star formation was the domain of astronomers. All this has changed starting with Tom Gehrels who organized the first Protostars and Planets conference in January 1978 in Tucson. In the book that followed this conference, which was edited by Gehrels, he expressed the hope “to develop the interface between studies of star formation and those of the origin of the solar system.” This hope has been fulfilled beyond expectations. The first volume has been followed by four more in intervals of about seven years. Each book was preceded by a conference. The Protostars and Planets V Conference took place at the Hilton Waikoloa Village on the Big Island of Hawai‘i on October 24–28, 2005. The subsequent book appeared early this year. As its forerunners, it is part of the University of Arizona The arrangement of the chapters roughly follows the Space Science Series, which is devoted to different aspects of inferred prehistory of our own solar system. In the dense core solar system science. of a molecular cloud, gravity overcomes thermal and The rapid growth of this new interdisciplinary field magnetic pressures, leading to the formation of a star, in most between astronomy and planetary science is demonstrated by case actually of a binary star system.
    [Show full text]
  • ET First Extract
    May 2018 Evangelical TIMES 23 What is man (1): Are we alone in the universe? The first of three edited extracts from Edgar Andrews’ new book, What is Man? Adam, alien or ape? Prof Edgar Andrews It’s easy to confuse SETI with YETI because both relate to are more likely to swallow small bugs than little green men. the National Science Foundation, Ohio State University began creatures that probably don’t exist. The Yeti is a proverbial I should make it clear that the planet’s discoverers said constructing a radio observatory called ‘Big Ear’ — which beast that inhabits the Himalayas and walks upright like a nothing about bugs — that was an invention by the BBC. later undertook the world’s first continuous SETI program. human, but leaves huge footprints in the snow and strikes But their claim that Gliese 581c is a rocky planet like Earth On 15 August 1977, Jerry Ehman, a project volunteer at fear into the local populace. Related to America’s Bigfoot, it and has liquid water on its surface is itself based on a string the observatory, observed a strong signal and wrote ‘Wow!’ is sometimes called the Abominable Snowman (apparently of assumptions. on the recorded trace. Unsurprisingly known as the Wow! due to a mistranslation of its Nepalese name). An informed website respondent commented: ‘You must signal, some enthusiasts consider it the best candidate to date SETI, on the other hand, stands for ‘the search for extra- remember that neither the mass nor the radius of this planet for a cosmic radio signal from an artificial source.
    [Show full text]
  • Links to Education Standards • Introduction to Exoplanets • Glossary of Terms • Classroom Activities Table of Contents Photo © Michael Malyszko Photo © Michael
    an Educator’s Guid E INSIDE • Links to Education Standards • Introduction to Exoplanets • Glossary of Terms • Classroom Activities Table of Contents Photo © Michael Malyszko Photo © Michael For The TeaCher About This Guide .............................................................................................................................................. 4 Connections to Education Standards ................................................................................................... 5 Show Synopsis .................................................................................................................................................. 6 Meet the “Stars” of the Show .................................................................................................................... 8 Introduction to Exoplanets: The Basics .................................................................................................. 9 Delving Deeper: Teaching with the Show ................................................................................................13 Glossary of Terms ..........................................................................................................................................24 Online Learning Tools ..................................................................................................................................26 Exoplanets in the News ..............................................................................................................................27 During
    [Show full text]
  • Habitability of Super-Earths: Gliese 581C & 581D
    Exoplanets: Detection, Formation and Dynamics Proceedings IAU Symposium No. 249, 2007 c 2008 International Astronomical Union Y.-S. Sun, S. Ferraz-Mello and J.-L. Zhou, eds. doi:10.1017/S1743921308017031 Habitability of super-Earths: Gliese 581c & 581d W. von Bloh1, C. Bounama1,M.Cuntz2 and S. Franck1 1 Potsdam Institute for Climate Impact Research, P.O. Box 601203, Potsdam, Germany, email: [email protected], [email protected], [email protected] 2 University of Texas at Arlington, P.O. Box 19059, Arlington, TX 76019, USA email: [email protected] Abstract. The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses smaller than 10 Earth masses. Unlike the larger exoplanets previously found, these smaller planets are more likely to have similar chemical and mineralogical composition to the Earth. We present a thermal evolution model for super-Earth planets to identify the sources and sinks of atmospheric carbon dioxide. The photosynthesis-sustaining habitable zone (pHZ) is determined by the limits of biological productivity on the planetary surface. We apply our model to calculate the habitability of the two super-Earths in the Gliese 581 system. The super-Earth Gl 581c is clearly outside the pHZ, while Gl 581d is at the outer edge of the pHZ. Therefore, it could at least harbor some primitive forms of life. Keywords. Astrobiology, planetary systems, stars: individual (Gliese 581) 1. Introduction Very recently, Udry et al. (2007) announced the detection of two super-Earth planets in the Gliese 581 system; namely, Gl 581c with a mass of 5.06 M⊕ and a semi-major axis of 0.073 AU, and Gl 581d with 8.3 M⊕ and 0.25 AU.
    [Show full text]
  • Binary Asteroids and the Formation of Doublet Craters
    ICARUS 124, 372±391 (1996) ARTICLE NO. 0215 Binary Asteroids and the Formation of Doublet Craters WILLIAM F. BOTTKE,JR. Division of Geological and Planetary Sciences, California Institute of Technology, Mail Code 170-25, Pasadena, California 91125 E-mail: [email protected] AND H. JAY MELOSH Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721 Received April 29, 1996; revised August 14, 1996 found we could duplicate the observed fraction of doublet cra- At least 10% (3 out of 28) of the largest known impact craters ters found on Earth, Venus, and Mars. Our results suggest on Earth and a similar fraction of all impact structures on that any search for asteroid satellites should place emphasis Venus are doublets (i.e., have a companion crater nearby), on km-sized Earth-crossing asteroids with short-rotation formed by the nearly simultaneous impact of objects of compa- periods. 1996 Academic Press, Inc. rable size. Mars also has doublet craters, though the fraction found there is smaller (2%). These craters are too large and too far separated to have been formed by the tidal disruption 1. INTRODUCTION of an asteroid prior to impact, or from asteroid fragments dispersed by aerodynamic forces during entry. We propose that Two commonly held paradigms about asteroids and some fast rotating rubble-pile asteroids (e.g., 4769 Castalia), comets are that (a) they are composed of non-fragmented after experiencing a close approach with a planet, undergo tidal chunks of rock or rock/ice mixtures, and (b) they are soli- breakup and split into multiple co-orbiting fragments.
    [Show full text]
  • Habitable Planets Around the Star Gl 581? Franck Selsis, J
    Habitable planets around the star Gl 581? Franck Selsis, J. F. Kasting, B. Levrard, J. Paillet, I. Ribas, X. Delfosse To cite this version: Franck Selsis, J. F. Kasting, B. Levrard, J. Paillet, I. Ribas, et al.. Habitable planets around the star Gl 581?. Astronomy and Astrophysics - A&A, EDP Sciences, 2007, accepted for publication. hal-00182743v1 HAL Id: hal-00182743 https://hal.archives-ouvertes.fr/hal-00182743v1 Submitted on 27 Oct 2007 (v1), last revised 21 Nov 2007 (v3) HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Astronomy & Astrophysics manuscript no. Selsis˙Gl581.hyper26490 c ESO 2007 October 28, 2007 Habitable planets around the star Gl 581? F. Selsis1,2, J. F. Kasting3, B. Levrard4,1 J. Paillet5, I. Ribas6, and X. Delfosse7 1 CRAL: Centre de Recherche Astrophysique de Lyon (CNRS; Universit´ede Lyon; Ecole Normale Sup´erieure de Lyon), 46 all´ee d’Italie, F-69007, Lyon, France, e-mail: [email protected] 2 LAB: Laboratoire d’Astrophysique de Bordeaux (CNRS; Universit´eBordeaux I), BP 89, F-33270 Floirac, France 3 Dept. of Geosciences,
    [Show full text]
  • Humanity and Space
    10/17/2012!! !!!!!! Project Number: MH-1207 Humanity and Space An Interactive Qualifying Project Submitted to WORCESTER POLYTECHNIC INSTITUTE In partial fulfillment for the Degree of Bachelor of Science by: Matthew Beck Jillian Chalke Matthew Chase Julia Rugo Professor Mayer H. Humi, Project Advisor Abstract Our IQP investigates the possible functionality of another celestial body as an alternate home for mankind. This project explores the necessary technological advances for moving forward into the future of space travel and human development on the Moon and Mars. Mars is the optimal candidate for future human colonization and a stepping stone towards humanity’s expansion into outer space. Our group concluded space travel and interplanetary exploration is possible, however international political cooperation and stability is necessary for such accomplishments. 2 Executive Summary This report provides insight into extraterrestrial exploration and colonization with regards to technology and human biology. Multiple locations have been taken into consideration for potential development, with such qualifying specifications as resources, atmospheric conditions, hazards, and the environment. Methods of analysis include essential research through online media and library resources, an interview with NASA about the upcoming Curiosity mission to Mars, and the assessment of data through mathematical equations. Our findings concerning the human aspect of space exploration state that humanity is not yet ready politically and will not be able to biologically withstand the hazards of long-term space travel. Additionally, in the field of robotics, we have the necessary hardware to implement adequate operational systems yet humanity lacks the software to implement rudimentary Artificial Intelligence. Findings regarding the physics behind rocketry and space navigation have revealed that the science of spacecraft is well-established.
    [Show full text]
  • Habitability of Super-Earths: Gliese 581C and 581D
    Exoplanets: Detection, Formation & Dynamics Proceedings IAU Symposium No. 249, 2008 c 2008 International Astronomical Union A.C. Editor, B.D. Editor & C.E. Editor, eds. DOI: 00.0000/X000000000000000X Habitability of super-Earths: Gliese 581c & 581d W. von Bloh1, C. Bounama1, M. Cuntz2 and S. Franck1 1 Potsdam Institute for Climate Impact Research, P.O. Box 601203, Potsdam, Germany, email: [email protected], [email protected], [email protected] 2 University of Texas at Arlington, P.O. Box 19059, Arlington, TX 76019, USA email: [email protected] Abstract. The unexpected diversity of exoplanets includes a growing number of super-Earth planets, i.e., exoplanets with masses smaller than 10 Earth masses. Unlike the larger exoplanets previously found, these smaller planets are more likely to have similar chemical and mineralogical composition to the Earth. We present a thermal evolution model for super-Earth planets to identify the sources and sinks of atmospheric carbon dioxide. The photosynthesis-sustaining habitable zone (pHZ) is determined by the limits of biological productivity on the planetary surface. We apply our model to calculate the habitability of the two super-Earths in the Gliese 581 system. The super-Earth Gl 581c is clearly outside the pHZ, while Gl 581d is at the outer edge of the pHZ. Therefore, it could at least harbor some primitive forms of life. Keywords. Astrobiology, planetary systems, stars: individual (Gliese 581) 1. Introduction Very recently, Udry et al. (2007) announced the detection of two super-Earth planets in the Gliese 581 system; namely, Gl 581c with a mass of 5.06 M⊕ and a semi-major axis of 0.073 AU, and Gl 581d with 8.3 M⊕ and 0.25 AU.
    [Show full text]
  • The Terrestrial Planet V Hypothesis As the Mechanism for the Origin of the Late Heavy Bombardment
    A&A 535, A41 (2011) Astronomy DOI: 10.1051/0004-6361/201117336 & c ESO 2011 Astrophysics The terrestrial Planet V hypothesis as the mechanism for the origin of the late heavy bombardment R. Brasser and A. Morbidelli Dep. Cassiopée, University of Nice–Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, 06304 Nice, France e-mail: [email protected] Received 24 May 2011 / Accepted 13 September 2011 ABSTRACT In this study we attempt to model, with numerical simulations, the scenario for the origin of the late heavy bombardment (LHB) proposed in Chambers (2007, Icarus, 189, 386). Chambers suggested that the orbit of a fictitious sub-Mars sized embryo outside Mars became unstable and crossed a part of the asteroid belt until it was removed through ejection or collision. Chambers demonstrated that this kind of evolution can occur at the LHB time, but he did not check whether enough material could be liberated from the belt to be consistent with the magnitude of the LHB. We do that here. In addition to the asteroid belt, we also consider putative belts of small objects located between the orbits of the Earth and Venus (EV belt) or between the Earth and Mars (EM belt). We find that delivering enough material to the Moon from the asteroid belt requires at least a 5 lunar mass embryo crossing the entire asteroid belt up to 3.3 AU for longer than 300 Myr on a low-inclination orbit. We do not witness this to occur in over a hundred simulations. An alternative approach, which relies only on decimating the inner belt (<2.5 AU), requires that the inner belt originally contained 4 to 13 times more mass than the original outer belt.
    [Show full text]
  • SIG #1:Towards a Much Needed Consensus in the Exoplanet Community
    SIG #1:Towards A much Needed Consensus in the Exoplanet Community 1.0 Sun M0 M1 • O M2 M / 10 M 5 M 10 M M3 E at K = 3 m/s E at K = 10 m/s E at K = 3 m/s M5 0.1 0.1 1.0 10.0 Distance (AU) Figure 1 The Habitable Zone around main sequence stars, and the velocity semi-amplitude of the Doppler wobble induced by 5 and 10 Earth-mass planets on the star. Venus, Earth and Mars are shown as colored dots. wobble caused by a terrestrial-mass planet. RV studies have uncovered planetary systems around 20 M dwarfs to date, including the low mass planetary system around GJ581,3 and KOI-961.4 These observations⇠ suggest that, while hot Jupiters may be rare in M star systems,5 lower mass planets do exist around M stars and may be rather common. Theoretical work based on core-accretion models and simulations also predicts that short period Neptune mass planets should be common around M stars.6 Climate simulations of planets in the HZ around M stars7 show that tidal locking does not necessarily lead to atmospheric collapse The habitability of terrestrial planets around M stars has also been explored by many groups8 As seen in Figure 1, a 10 Earth-mass planets in the HZ are already detectable at more than 3σ with a velocity precision of 3m/s, and an instrument capable of 1-3m/s precision will have the sensitivity to discover terrestrial mass planets around the majority of mid-late M dwarfs.
    [Show full text]
  • Mathematics for Input Space Probes in the Atmosphere of Gliese 581D
    Parana Journal of Science and Education, v.2, n.5, (6-13) July 14, 2016 PJSE, ISSN 2447-6153, c 2015-2016 https://sites.google.com/site/pjsciencea/ Mathematics for input space probes in the atmosphere of Gliese 581d R. Gobato1, A. Gobato2 and D. F. G. Fedrigo3 Abstract The work is a mathematical approach to the entry of an aerospace vehicle, as a probe or capsule in the atmosphere of the planet Gliese 581d, using data collected from the results of atmospheric models of the planet. GJ581d was the first planet candidate of a few Earth masses reported in the circum-stellar habitable zone of another star. It is located in the Gliese 581 star system, is a star red dwarf about 20 light years away from Earth in the constellation Libra. Its estimated mass is about a third of that of the Sun. It has been suggested that the recently discovered exoplanet GJ581d might be able to support liquid water due to its relatively low mass and orbital distance. However, GJ581d receives 35% less stellar energy than the planet Mars and is probably locked in tidal resonance, with extremely low insolation at the poles and possibly a permanent night side. The climate that demonstrate GJ581d will have a stable atmosphere and surface liquid water for a wide range of plausible cases, making it the first confirmed super-Earth (2-10 Earth masses) in the habitable zone. According to the general principle of relativity, “All systems of reference are equivalent with respect to the formulation of the fundamental laws of physics.” In this case all the equations studied apply to the exoplanet Gliese 581d.
    [Show full text]
  • Art on Mars: a Foundation for Exoart
    THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF CANBERRA AUSTRALIA by TREVOR JOHN RODWELL Bachelor of Design (Hons), University of South Australia Graduate Diploma (Business Enterprise), The University of Adelaide ART ON MARS: A FOUNDATION FOR EXOART May 2011 ABSTRACT ART ON MARS: A FOUNDATION FOR EXOART It could be claimed that human space exploration started when the former Soviet Union (USSR) launched cosmonaut Yuri Gagarin into Earth orbit on 12 April 1961. Since that time there have been numerous human space missions taking American astronauts to the Moon and international crews to orbiting space stations. Several space agencies are now working towards the next major space objective which is to send astronauts to Mars. This will undoubtedly be the most complex and far-reaching human space mission ever undertaken. Because of its large scale and potentially high cost it is inevitable that such a mission will be an international collaborative venture with a profile that will be world- wide. Although science, technology and engineering have made considerable contributions to human space missions and will be very much involved with a human Mars mission, there has been scant regard for artistic and cultural involvement in these missions. Space agencies have, however, realised the influence of public perception on space funding outcomes and for some time have strived to engage the public in these space missions. This has provided an opportunity for an art and cultural involvement, but there is a problem for art engaging with space missions as currently there is no artform specific to understanding and tackling the issues of art beyond our planet.
    [Show full text]