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Limits from the Hubble Space Telescope on a Point Source in SN 1987A
Limits from the Hubble Space Telescope on a Point Source in SN 1987A The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Graves, Genevieve J. M., Peter M. Challis, Roger A. Chevalier, Arlin Crotts, Alexei V. Filippenko, Claes Fransson, Peter Garnavich, et al. 2005. “Limits from the Hubble Space Telescopeon a Point Source in SN 1987A.” The Astrophysical Journal 629 (2): 944–59. https:// doi.org/10.1086/431422. Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:41399924 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA The Astrophysical Journal, 629:944–959, 2005 August 20 # 2005. The American Astronomical Society. All rights reserved. Printed in U.S.A. LIMITS FROM THE HUBBLE SPACE TELESCOPE ON A POINT SOURCE IN SN 1987A Genevieve J. M. Graves,1, 2 Peter M. Challis,2 Roger A. Chevalier,3 Arlin Crotts,4 Alexei V. Filippenko,5 Claes Fransson,6 Peter Garnavich,7 Robert P. Kirshner,2 Weidong Li,5 Peter Lundqvist,6 Richard McCray,8 Nino Panagia,9 Mark M. Phillips,10 Chun J. S. Pun,11,12 Brian P. Schmidt,13 George Sonneborn,11 Nicholas B. Suntzeff,14 Lifan Wang,15 and J. Craig Wheeler16 Received 2005 January 27; accepted 2005 April 26 ABSTRACT We observed supernova 1987A (SN 1987A) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST ) in 1999 September and again with the Advanced Camera for Surveys (ACS) on the HST in 2003 November. -
A Dozen Colliding Wind X-Ray Binaries in the Star Cluster R 136 in the 30 Doradus Region
A dozen colliding wind X-ray binaries in the star cluster R 136 in the 30 Doradus region Simon F. Portegies Zwart?,DavidPooley,Walter,H.G.Lewin Massachusetts Institute of Technology, Cambridge, MA 02139, USA ? Hubble Fellow Subject headings: stars: early-type — tars: Wolf-Rayet — galaxies:) Magellanic Clouds — X-rays: stars — X-rays: binaries — globular clusters: individual (R136) –2– ABSTRACT We analyzed archival Chandra X-ray observations of the central portion of the 30 Doradus region in the Large Magellanic Cloud. The image contains 20 32 35 1 X-ray point sources with luminosities between 5 10 and 2 10 erg s− (0.2 × × — 3.5 keV). A dozen sources have bright WN Wolf-Rayet or spectral type O stars as optical counterparts. Nine of these are within 3:4 pc of R 136, the ∼ central star cluster of NGC 2070. We derive an empirical relation between the X-ray luminosity and the parameters for the stellar wind of the optical counterpart. The relation gives good agreement for known colliding wind binaries in the Milky Way Galaxy and for the identified X-ray sources in NGC 2070. We conclude that probably all identified X-ray sources in NGC 2070 are colliding wind binaries and that they are not associated with compact objects. This conclusion contradicts Wang (1995) who argued, using ROSAT data, that two earlier discovered X-ray sources are accreting black-hole binaries. Five early type stars in R 136 are not bright in X-rays, possibly indicating that they are either: single stars or have a low mass companion or a wide orbit. -
The Evolution of Star Habitable Zones
The Evolution of Star Habitable Zones Jeffrey J. Wolynski November 17, 2018 Rockledge, FL 32922 Abstract: It was discovered that planets are older, evolving stars. This means the Circumstellar Habitable Zone collapses and/or shrinks into the star itself, thus evolves as the star evolves. Explanation is provided. The habitable zone of a star is the area where liquid water exists or can exist. Since stars cool down and become water worlds as they evolve, combining their hydrogen with the leftover oxygen in large amounts, it is easy to see what happens. The star is too hot in the beginning to form water, or sustain it, but it can heat up other much colder stars allowing them to pool water on their surfaces from a distance. As the star cools and evolves, the distance it can do this diminishes considerably and its habitable zone shrinks. Blue giants have the largest habitable zones, but they quickly contract because they are so young and are evolving rapidly to cooler, less massive states. What this means is that the time variable for the habitable zones of these objects is quite small. The activity of more evolved stars around blue giants should be short-lived, but interesting to say the least. White stars have smaller habitable zones but are still very large. Orange dwarfs have even smaller habitable zones, as well show a noticeable thinning of the zone as opposed to earlier stages. Red dwarfs have very small external habitable zones and the smallest external habitable zone belongs to only the smallest brown dwarfs, which still have a small amount of heat to radiate the surface of another more evolved star. -
Water, Habitability, and Detectability Steve Desch
Water, Habitability, and Detectability Steve Desch PI, “Exoplanetary Ecosystems” NExSS team School of Earth and Space Exploration, Arizona State University with Ariel Anbar, Tessa Fisher, Steven Glaser, Hilairy Hartnett, Stephen Kane, Susanne Neuer, Cayman Unterborn, Sara Walker, Misha Zolotov Astrobiology Science Strategy NAS Committee, Beckmann Center, Irvine, CA (remotely), January 17, 2018 How to look for life on (Earth-like) exoplanets: find oxygen in their atmospheres How Earth-like must an exoplanet be for this to work? Seager et al. (2013) How to look for life on (Earth-like) exoplanets: find oxygen in their atmospheres Oxygen on Earth overwhelmingly produced by photosynthesizing life, which taps Sun’s energy and yields large disequilibrium signature. Caveats: Earth had life for billions of years without O2 in its atmosphere. First photosynthesis to evolve on Earth was anoxygenic. Many ‘false positives’ recognized because O2 has abiotic sources, esp. photolysis (Luger & Barnes 2014; Harman et al. 2015; Meadows 2017). These caveats seem like exceptions to the ‘rule’ that ‘oxygen = life’. How non-Earth-like can an exoplanet be (especially with respect to water content) before oxygen is no longer a biosignature? Part 1: How much water can terrestrial planets form with? Part 2: Are Aqua Planets or Water Worlds habitable? Can we detect life on them? Part 3: How should we look for life on exoplanets? Part 1: How much water can terrestrial planets form with? Theory says: up to hundreds of oceans’ worth of water Trappist-1 system suggests hundreds of oceans, especially around M stars Many (most?) planets may be Aqua Planets or Water Worlds How much water can terrestrial planets form with? Earth- “snow line” Standard Sun distance models of distance accretion suggest abundant water. -
The Multifaceted Planetesimal Formation Process
The Multifaceted Planetesimal Formation Process Anders Johansen Lund University Jurgen¨ Blum Technische Universitat¨ Braunschweig Hidekazu Tanaka Hokkaido University Chris Ormel University of California, Berkeley Martin Bizzarro Copenhagen University Hans Rickman Uppsala University Polish Academy of Sciences Space Research Center, Warsaw Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans-Neptunian objects and comets provide a unique record of the physical conditions in the solar nebula. Debris from planetesimal collisions around other stars signposts that the planetesimal formation process, and hence planet formation, is ubiquitous in the Galaxy. The planetesimal formation stage extends from micrometer-sized dust and ice to bodies which can undergo run-away accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking, fragmentation and radial drift. Two promising growth pathways are mass transfer, where small aggregates transfer up to 50% of their mass in high-speed collisions with much larger targets, and fluffy growth, where aggregate cross sections and sticking probabilities are enhanced by a low internal density. A wide range of particle sizes, from mm to 10 m, concentrate in the turbulent gas flow. Overdense filaments fragment gravitationally into bound particle clumps, with most mass entering planetesimals of contracted radii from 100 to 500 km, depending on local disc properties. -
2-6-NASA Exoplanet Archive
The NASA Exoplanet Archive Rachel Akeson NASA Exoplanet Science Ins5tute (NExScI) September 29, 2016 NASA Big Data Task Force Overview: Dat a NASA Exoplanet Archive supports both the exoplanet science community and NASA exoplanet missions (Kepler, K2, TESS, WFIRST) • Data • Confirmed exoplanets from the literature • Over 80,000 planetary and stellar parameter values for 3388 exoplanets • Updated weekly • Kepler stellar proper5es, planet candidate, data valida5on and occurrence rate products • MAST is archive for pixel and light curve data • Addi5onal space (CoRoT) and ground-based transit surveys (~20 million light curves) • Transit spectroscopy data • Auto-updated exoplanet plots and movies Big Data Task Force: Exoplanet Archive Overview: Tool s Example: Kepler 14 Time Series Viewer • Interac5ve tables and ploZng for data • Includes light curve normaliza5on • Periodogram calcula5ons • Searches for periodic signals in archive or user-supplied light curves • Transit predic5ons • Uses value from archive to predict future planet transits for observa5on and mission planning • URL-based queries Aliases • Calcula5on of observable proper5es Planet orbital period • Web-based service to collect follow-up observa5ons of planet candidates for Kepler, K2 and TESS (ExoFOP) Stellar ac5vity • Includes user-supplied data, file and notes Big Data Task Force: Exoplanet Archive Data Challenges and Technical Approach (1) • Challenges with Exoplanet Archive are not currently about data volume but about providing CPU resources and data complexity • CPU challenge -
Formation of the Solar System (Chapter 8)
Formation of the Solar System (Chapter 8) Based on Chapter 8 • This material will be useful for understanding Chapters 9, 10, 11, 12, 13, and 14 on “Formation of the solar system”, “Planetary geology”, “Planetary atmospheres”, “Jovian planet systems”, “Remnants of ice and rock”, “Extrasolar planets” and “The Sun: Our Star” • Chapters 2, 3, 4, and 7 on “The orbits of the planets”, “Why does Earth go around the Sun?”, “Momentum, energy, and matter”, and “Our planetary system” will be useful for understanding this chapter Goals for Learning • Where did the solar system come from? • How did planetesimals form? • How did planets form? Patterns in the Solar System • Patterns of motion (orbits and rotations) • Two types of planets: Small, rocky inner planets and large, gas outer planets • Many small asteroids and comets whose orbits and compositions are similar • Exceptions to these patterns, such as Earth’s large moon and Uranus’s sideways tilt Help from Other Stars • Use observations of the formation of other stars to improve our theory for the formation of our solar system • Use this theory to make predictions about the formation of other planetary systems Nebular Theory of Solar System Formation • A cloud of gas, the “solar nebula”, collapses inwards under its own weight • Cloud heats up, spins faster, gets flatter (disk) as a central star forms • Gas cools and some materials condense as solid particles that collide, stick together, and grow larger Where does a cloud of gas come from? • Big Bang -> Hydrogen and Helium • First stars use this -
Composition and Accretion of the Terrestrial Planets
Lunar and Planetary Science XXXI 1546.pdf COMPOSITION AND ACCRETION OF THE TERRESTRIAL PLANETS. Edward R. D. Scott and G. Jeffrey Taylor, Hawai’i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, Univer- sity of Hawai’i at Manoa, Honolulu, Hawai’i 96822, USA; [email protected] Abstract: Compositional variations among the spread gravitational mixing of the embryos and their four terrestrial planets are generally attributed to giant 20 impacts [1] rather than to primordial chemical varia- Fig. 2 tions among planetesimals [e.g., 2]. This is largely be- Mars cause modeling suggests that each terrestrial planet ac- 15 creted material from the whole of the inner solar sys- tem [1], and because Mercury’s high density is attrib- 10 Venus Earth uted to mantle stripping in a giant impact [3] and not to its position as the innermost planet [4]. However, Mer- Mercury cury’s high concentration of metallic iron and low con- 5 centration of oxidized iron are comparable to those in recently discovered metal-rich chondrites [5-7]. Since E 0 chondrites are linked isotopically with the Earth, we 0 0.5 1 1.5 2 suggest that Mercury may have formed from metal-rich chondritic material. Venus and Earth have similar con- Semi-major Axis (AU) centrations of metallic and oxidized iron that are inter- fragments, which ensured that each terrestrial planet mediate between those of Mercury and Mars consistent formed from material originally located throughout the with wide, overlapping accretion zones [1]. However, inner solar system (0.5 to 2.5 AU). -
POSSIBLE STRUCTURE MODELS for the TRANSITING SUPER-EARTHS:KEPLER-10B and 11B
43rd Lunar and Planetary Science Conference (2012) 1290.pdf POSSIBLE STRUCTURE MODELS FOR THE TRANSITING SUPER-EARTHS:KEPLER-10b AND 11b. P. Futó1 1 Department of Physical Geography, University of West Hungary, Szombathely, Károlyi Gáspár tér, H- 9700, Hungary ([email protected]) Introduction:Up to january of 2012,10 super- The planet Kepler-11b has a large radius (1.97 R⊕) for Earths have been announced by Kepler-mission [1] its mass (4.3 M⊕),therefore this planet must have a that is designed to detect hundreds of transiting exo- spherical shell that is composed of low-density materi- planets.Kepler was launched on 6th March,2009 and the als.Considering the planet's average density,it must primary purpose of its scientific program is to search have a metallic core with different possible fractional for terrestrial-sized planets in the habitable zone of mass.Accordinghly,I have made a possible structure Solar-like stars.For the case of high number of discov- model for Kepler-11b in which the selected core mass eries we will be able to estimate the frequency of fraction is 32.59% (similarly to that of Earth) and the Earth-sized planets in our galaxy.Results of the Kepler- water ice layer has a relatively great fractional 's measurements show that the small-sized planets are volume.For case of the selected composition, the icy frequent in the spiral galaxies.A catalog of planetary surface sublimated to form a water vapor as the planet candidates,including objects with small-sized candidate moved inward the central star during its migration. -
The Subsurface Habitability of Small, Icy Exomoons J
A&A 636, A50 (2020) Astronomy https://doi.org/10.1051/0004-6361/201937035 & © ESO 2020 Astrophysics The subsurface habitability of small, icy exomoons J. N. K. Y. Tjoa1,?, M. Mueller1,2,3, and F. F. S. van der Tak1,2 1 Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands e-mail: [email protected] 2 SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands 3 Leiden Observatory, Leiden University, Niels Bohrweg 2, 2300 RA Leiden, The Netherlands Received 1 November 2019 / Accepted 8 March 2020 ABSTRACT Context. Assuming our Solar System as typical, exomoons may outnumber exoplanets. If their habitability fraction is similar, they would thus constitute the largest portion of habitable real estate in the Universe. Icy moons in our Solar System, such as Europa and Enceladus, have already been shown to possess liquid water, a prerequisite for life on Earth. Aims. We intend to investigate under what thermal and orbital circumstances small, icy moons may sustain subsurface oceans and thus be “subsurface habitable”. We pay specific attention to tidal heating, which may keep a moon liquid far beyond the conservative habitable zone. Methods. We made use of a phenomenological approach to tidal heating. We computed the orbit averaged flux from both stellar and planetary (both thermal and reflected stellar) illumination. We then calculated subsurface temperatures depending on illumination and thermal conduction to the surface through the ice shell and an insulating layer of regolith. We adopted a conduction only model, ignoring volcanism and ice shell convection as an outlet for internal heat. -
Planetary Science
Scientific Research National Aeronautics and Space Administration Planetary Science MSFC planetary scientists are active in Peering into the history The centerpiece of the Marshall efforts is research at Marshall, building on a long history of the solar system the Marshall Noble Gas Research Laboratory of scientific support to NASA’s human explo- (MNGRL), a unique facility within NASA. Noble- ration program planning, whether focused Marshall planetary scientists use multiple anal- gas isotopes are a well-established technique on the Moon, asteroids, or Mars. Research ysis techniques to understand the formation, for providing detailed temperature-time histories areas of expertise include planetary sample modification, and age of planetary materials of rocks and meteorites. The MNGRL lab uses analysis, planetary interior modeling, and to learn about their parent planets. Sample Ar-Ar and I-Xe radioactive dating to find the planetary atmosphere observations. Scientists analysis of this type is well-aligned with the formation age of rocks and meteorites, and at Marshall are involved in several ongoing priorities for scientific research and analysis Ar/Kr/Ne cosmic-ray exposure ages to under- planetary science missions, including the Mars in NASA’s Planetary Science Division. Multiple stand when the meteorites were launched from Exploration Rovers, the Cassini mission to future missions are poised to provide new their parent planets. Saturn, and the Gravity Recovery and Interior sample-analysis opportunities. Laboratory (GRAIL) mission to the Moon. Marshall is the center for program manage- ment for the Agency’s Discovery and New Frontiers programs, providing programmatic oversight into a variety of missions to various planetary science destinations throughout the solar system, from MESSENGER’s investiga- tions of Mercury to New Frontiers’ forthcoming examination of the Pluto system. -
The Evolving Universe and the Origin of Life
Pekka Teerikorpi · Mauri Valtonen · Kirsi Lehto · Harry Lehto · Gene Byrd · Arthur Chernin The Evolving Universe and the Origin of Life The Search for Our Cosmic Roots Second Edition The Evolving Universe and the Origin of Life Pekka Teerikorpi • Mauri Valtonen • Kirsi Lehto • Harry Lehto • Gene Byrd • Arthur Chernin The Evolving Universe and the Origin of Life The Search for Our Cosmic Roots Second Edition 123 Pekka Teerikorpi Mauri Valtonen Department of Physics and Astronomy Department of Physics and Astronomy University of Turku University of Turku Turku, Finland Turku, Finland Kirsi Lehto Harry Lehto Department of Biology Department of Physics and Astronomy University of Turku University of Turku Turku, Finland Turku, Finland Gene Byrd Arthur Chernin Department of Physics and Astronomy Sternberg Astronomical Institute The University of Alabama Moscow University Tuscaloosa, AL, USA Moscow, Russia ISBN 978-3-030-17920-5 ISBN 978-3-030-17921-2 (eBook) https://doi.org/10.1007/978-3-030-17921-2 1st edition: © 2009 Springer Science+Business Media, LLC 2nd edition: © Springer Nature Switzerland AG 2019 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.