This week on HST


HST Programs: September 27, 2010 - October 3, 2010

Program Number Principal Investigator Program Title
11526 James C. Green, University of Colorado at Boulder COS-GTO: Sampling the Local ISM with hot white dwarfs
11535 James C. Green, University of Colorado at Boulder COS-GTO: Deep Search for an Oxygen Atmosphere on Callisto
11572 David Kent Sing, CNRS, Institut d'Astrophysique de Paris Charaterizing Atmospheric Sodium in the Transiting hot-Jupiter HD189733b
11575 Schuyler D. Van Dyk, Jet Propulsion Laboratory The Stellar Origins of Supernovae
11598 Jason Tumlinson, Space Telescope Science Institute How Galaxies Acquire their Gas: A Map of Multiphase Accretion and Feedback in Gaseous Galaxy Halos
11605 Travis Stuart Barman, Lowell Observatory Obtaining the Missing Links in the Test of Very Low Mass Evolutionary Models with HST
11635 Michael Shara, American Museum of Natural History In Search of SNIb/Ic Wolf-Rayet Progenitors and Comparison with Red Supergiants {SNII Progenitors} in the Giant ScI Spiral M101
11644 Michael E Brown, California Institute of Technology A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system
11664 Thomas M. Brown, Space Telescope Science Institute The WFC3 Galactic Bulge Treasury Program: Populations, Formation History, and Planets
11677 Harvey B. Richer, University of British Columbia Is 47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a Hubble Legacy
11691 Paul Goudfrooij, Space Telescope Science Institute Using Massive Star Clusters in Merger Remnants To Provide Reference Colors of Intermediate-Age Stellar Populations
11694 David R. Law, University of California - Los Angeles Mapping the Interaction between High-Redshift Galaxies and the Intergalactic Environment
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies
11729 Jon A. Holtzman, New Mexico State University Photometric Metallicity Calibration with WFC3 Specialty Filters
12015 Suvi Gezari, The Johns Hopkins University Rapid Follow-Up Observations of Tidal Disruption Events Discovered by Pan-STARRS1
12041 James C. Green, University of Colorado at Boulder COS-GTO: Io Atmosphere/STIS
12166 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12181 Drake Deming, NASA Goddard Space Flight Center The Atmospheric Structure of Giant Hot Exoplanets
12209 Adam S. Bolton, University of Utah A Strong Lensing Measurement of the Evolution of Mass Structure in Giant Elliptical Galaxies
12210 Adam S. Bolton, University of Utah SLACS for the Masses: Extending Strong Lensing to Lower Masses and Smaller Radii
12213 Roelof S. de Jong, Astrophysikalisches Institut Potsdam The Stellar Halo Profiles of Massive Disk Galaxies
12215 Nancy R. Evans, Smithsonian Institution Astrophysical Observatory Searching for the Missing Low-Mass Companions of Massive Stars
12229 Linda J. Smith, Space Telescope Science Institute HST U-band Survey of Star Clusters in Nearby Star-Forming Galaxies
12237 William M. Grundy, Lowell Observatory Orbits, Masses, Densities, and Colors of Two Transneptunian Binaries
12248 Jason Tumlinson, Space Telescope Science Institute How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and Galactic Winds Below L*
12265 Masami Ouchi, Carnegie Institution of Washington Determining the Physical Nature of a Unique Giant Lya Emitter at z=6.595
12307 Andrew J. Levan, The University of Warwick A public SNAPSHOT survey of gamma-ray burst host galaxies
12310 Goeran Oestlin, Stockholm University LARS - The Lyman Alpha Reference Sample
12381 Patrizia A. Caraveo, CNR, Istituto di Astrofisica Spaziale Imaging the Crab nebula while it is flaring in gamma-rays

Selected highlights

GO 11572: Characterizing Atmospheric Sodium in the Transiting hot-Jupiter HD189733b

An artist's impression of the hot Jupiter circling a solar-type star HD 198733 is a 7th magnitude G5 dwarf that lies at a distance of ~20 parsecs from the Sun, in the direction of the constellation of Vulpecula. Like many other nearby solar-type stars, HD 189733 has an associated planetary system, including a hot Jupiter, a ~1.15 MJ gas giant with an orbital period of 2.12 days. Most significantly, that inner planet transits the central star, making HD 189733 the closest transiting system found so far. Transiting systems offer a potential gold-mine for extrasolar planetary studies, since not only is the orbital inclination well defined, but the diameter (and hence the average density) is directly measureable form the eclipse depth, while the atmospheric composition can be probed through line absorption or re-radiated thermal flux. The results from these measurments can be used to test, and improve, theoretical models of extrasolar planets. These observations are best done from space (indeed, the only successful atmospheric observations to date have been with HST and Spitzer). HD 189733 has already been studied extensively with HST using the grism on the Advanced Camera for Surveys and, at near-infrared wavelengths, NICMOS. However, it's discovery postdated the STIS electronic failure, so it has never been studied at even moderate spectral resolution. The present observations will use the G750M grating on STIS to monitor three transits, and the data will be analysed for the presence of enhanced sodium absorption, as previously detected in the original bright transiting planet, HD 209458b.

GO 11644: A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system

The architecture of the outer Solar System The Kuiper Belt lies beyond the orbit of Neptune, extending from ~30 AU to ~50 AU from the Sun, and includes at least 70,000 objects with diameters exceeding 100 km. Setting aside Pluto, the first trans-Neptunian objects were discovered in the early 1990s. Most are relatively modest in size, with diameters of a few hundred km and photometric properties that suggested an icy composition, similar to Pluto and its main satellite, Charon. Over the last three years, a handful of substantially larger bodies have been discovered, with diameters of more than 1000 km; one of the objects, 2003 UB313, is comparable in size to Pluto (2320 km.). At the same time, ground-based surveys, such as the Deep Ecliptic Survey, the Canada-France Ecliptic plane Survey and the Palomar Quest Survey, scanned the ecliptic for fainter, lower-mass objects, with the aim of using their properties to assess the likely chemical composition and dynamical history of the early Solar System. The present program will use Wide Field Camera 3 to push up to 2 magnitudes fainter than these ground-based studies, providing reliable estimates of compositions for a representative sample of KBOs.

GO 12181: The Atmospheric Structure of Giant Hot Exoplanets

Probing the atmosphere of a transiting exoplanet The first exoplanet, 51 Peg b, was discovered through radial velocity measurements in 1995. 51 Pegb was followed by a trickle, and then a flood of other discoveries, as astronomers realised that there were other solar systems radically different from our own, where "hot jupiters" led to short-period, high-amplitude velocity variations. Then, in 1999, came the inevitable discovery that one of those hot jupiters. HD 209458b, was in an orbit aligned with our line of sight to the star, resulting in transits. Since that date, the number of known transiting exoplanet systems has grown to more than 100, most detected through wide-field photometric surveys with the Kepler satellite providing the highest sensitivity dataset. These transiting systems are invaluable, since they not only provide unambiguous measurements of mass and diameter, but they also provide an opportunity to probe the atmospheric structure by differencing spectra taken during and between primary secondary transit. Such observations are best done from space: indeed, the only successful atmospheric observations to date have been with HST and Spitzer. The present program aims to set these measurements on a systematic basis by targeting 13 transiting exoplanets. The WFC3-IR G141 grism will be used to search for characteristic near-infrared spectral features in those systems.

GO 12381: Imaging the Crab nebula while it is flaring in gamma-rays

The Crab Nebula Messier 1, the Crab Nebula, presents one of astronomy's iconic images. The remnant of a bright supernova observed in 1054 by Arabian and Chinese astronomers, the Crab was first recorded in 1731 by the English astronomer, John Bevis, 37 years before Messier compiled his catalogue of non-comets. The energy source for the gaseous emission is the neutron star that lies in the centre of nebulosity, and was one of the first pulsars to be identified. The Crab is also a source of high energy emission, including gamma rays. Recently (September 19-21), the gamma ray flux was observed to double in strength by both the Fermi and Agile spacecrafts. Follow-up high-energy observations are being obtained with the Integral, Swift and Chandra observatories. The HST observations will be used to study the detailed structure of the complex knots and filaments, to search for further insight into the nature of this event.

Past weeks:
page by Neill Reid, updated 12/11/2010