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ANCIENT PLANETARY SYSTEMS ARE ORBITING A LARGE FRACTION OF WHITE DWARF STARS
Infrared studies have revealed debris likely related to planet formation in orbit around ~30% of youthful, intermediate mass, main-sequence stars. We present evidence, based on atmospheric pollutionExpand
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CHEMICAL ABUNDANCES IN THE EXTERNALLY POLLUTED WHITE DWARF GD 40: EVIDENCE OF A ROCKY EXTRASOLAR MINOR PLANET
We present Keck/High Resolution Echelle Spectrometer data with model atmosphere analysis of the helium-dominated polluted white dwarf GD 40, in which we measure atmospheric abundances relative toExpand
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Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity
The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populationsExpand
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AN ALUMINUM/CALCIUM-RICH, IRON-POOR, WHITE DWARF STAR: EVIDENCE FOR AN EXTRASOLAR PLANETARY LITHOSPHERE?
The presence of elements heavier than helium in white dwarf atmospheres is often a signpost for the existence of rocky objects that currently or previously orbited these stars. We have measured theExpand
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ROCKY EXTRASOLAR PLANETARY COMPOSITIONS DERIVED FROM EXTERNALLY POLLUTED WHITE DWARFS
We report Keck High Resolution Echelle Spectrometer data and model atmosphere analysis of two helium-dominated white dwarfs, PG1225?079 and HS2253+8023, whose heavy pollutions most likely derive fromExpand
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A giant planet candidate transiting a white dwarf.
Astronomers have discovered thousands of planets outside the Solar System1, most of which orbit stars that will eventually evolve into red giants and then into white dwarfs. During the red giantExpand
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Two Beyond-primitive Extrasolar Planetesimals
Using the Cosmic Origins Spectrograph on board the Hubble Space Telescope, we have obtained high-resolution ultraviolet observations of GD 362 and PG 1225-079, two helium-dominated, externallyExpand
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The inclusion of environmental education in science teacher education
Preface Alec M. Bodzin, Beth Shiner Klein, and Starlin Weaver PART I. INTRODUCTION TO ENVIRONMENTAL EDUCATION Chapter 1. The History and Philosophy of Environmental Education Robert L. Carter andExpand
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Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets
Peering inside extrasolar rocky bodies The oxygen fugacity of a rock, fO2, is a measure of how oxidizing or reducing its surroundings were when the rock formed. Different minerals form at differentExpand
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The Hyades Cluster: Identification of a Planetary System and Escaping White Dwarfs
Recently, some hot DA-type white dwarfs have been proposed to plausibly be escaping members of the Hyades. We used hydrogen Balmer lines to measure the radial velocities of seven such stars andExpand
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