This week on HST


HST Programs: October 1 - October 7, 2012

Cycle 20
Program Number Principal Investigator Program Title
12039 James C. Green, University of Colorado at Boulder COS-GTO: X-Ray Binaries
12116 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda and Triangulum Survey - Globular Cluster Sequence Calibrations
12281 Mark Clampin, NASA Goddard Space Flight Center STIS Coronagraphic Imaging of the Kuiper Belt Surrounding the HR 8799 Planetary System.
12448 Arlin Crotts, Columbia University in the City of New York Towards a Detailed Understanding of T Pyx, Its Outbursts and Shell
12458 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12492 Robert D. Mathieu, University of Wisconsin - Madison The Nature of the Binary Companions to the Blue Straggers in the Old Open Cluster NGC 188
12511 Travis Stuart Barman, Lowell Observatory Determining the Atmospheric Properties of Directly Imaged Planets
12550 Daniel Apai, University of Arizona Physics and Chemistry of Condensate Clouds across the L/T Transition - A SNAP Spectral Mapping Survey
12560 Roderick M. Johnstone, University of Cambridge COS spectra of a Filament in NGC1275 - Testing the Particle Heating Mechanism
12562 Geoffrey C. Clayton, Louisiana State University and A & M College The UV Interstellar Extinction Properties in the Super-Solar Metallicity Galaxy M31
12568 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
12573 Deborah Padgett, NASA Goddard Space Flight Center STIS Coronagraphy of New Debris Disks from the WISE All-Sky Survey
12582 Ariel Goobar, Stockholm University Probing the explosion environment and origin of Type Ia supernovae
12586 Kailash C. Sahu, Space Telescope Science Institute Detecting and Measuring the Masses of Isolated Black Holes and Neutron Stars through Astrometric Microlensing
12600 Reginald J. Dufour, Rice University Carbon and Nitrogen Enrichment Patterns in Planetary Nebulae
12685 Dean C. Hines, Space Telescope Science Institute Enabling Dark Energy Science for JWST and Beyond
12758 Thomas R. Ayres, University of Colorado at Boulder Alpha Cen: Climbing out of a Coronal Recession?
12813 Brian Schmidt, Australian National University Network of 13 high precision STIS spectrophotometric standards for ground based surveys
12879 Adam Riess, The Johns Hopkins University A 1% Measurement of the Distance Scale with Perpendicular Spatial Scanning
12915 Daniel J. Lennon, Space Telescope Science Institute - ESA PROPER MOTIONS OF ISOLATED MASSIVE STARS NEAR THE GALACTIC CENTER
12938 Sergio B. Dieterich, Georgia State University Research Foundation Probing Fundamental Stellar Parameters with HST/STIS Spectroscopy of M Dwarf Binaries
12940 Philip Massey, Lowell Observatory The Unevolved Massive Star Content of the Magellanic Clouds
12942 Eilat Glikman, Yale University Testing the Merger Hypothesis for Black Hole/Galaxy Co-Evolution at z~2
12947 Frederic E. Vincent, University of California - Davis determination of the line-spread function of the E140H grating with the 0.2 x 0.5 slit
12969 Peter Garnavich, University of Notre Dame Global Properties Are Not Enough: Probing the Local Environments of Type Ia Supernovae
12975 Simon J. Lilly, Eidgenossiche Technische Hochschule (ETH) Do winds transport magnetic fields out of high redshift galaxies?
12985 Kailash C. Sahu, Space Telescope Science Institute Determining the Mass of Proxima Centauri through Astrometric Microlensing
13021 Jacob L. Bean, University of Chicago Revealing the Diversity of Super-Earth Atmospheres
13050 Remco van den Bosch, Max-Planck-Institut fur Astronomie, Heidelberg The Most Massive Black Holes in Small Galaxies
13113 C. S. Kochanek, The Ohio State University ENERGY DEPENDENT X-RAY MICROLENSING AND THE STRUCTURE OF QUASARS

Selected highlights

GO 12281: STIS coronagraphic Imaging of the Kuiper Belt Surrounding the HR 8799 Planetary System


HST-NICMOS imaging of the three outer planets in the HR 8799 system
HR 8799 is bright A-type star, lying ~39 parsecs from the Sun within the constellation Pegasus. It is one of the youngest stars in the Solar Neighbourhood, with an age of roughly 30 million years, and is likely a member of the loose group known as the Columba Association. The star itself is a member of the Lambda Bootis class, a type of star that exhibits unusually weak metallic features, suggesting that the surface atmospheric layers are depleted in abundance. Possible explanations include accretion of metal-poor gas from a surrounding circumstellar disk. HR 8799's main claim to fame is as the first star to have direct imaging observations of an associated planetary system. In 2008, a Canadian team led by Christian Marois announced the discovery of three giant planet companions, denoted HR 8799b, c and d, at orbital separations from 24 to 68 AU. The discoveries were based on near-infrared adaptive-optics assisted observations with the Gemini North and Keck telescopes. The planets likely have masses between 5 and 10 times that of Jupiter. Subsequent observations revealed a fourth planet, HR8799e, lying at a projected distance of ~14.5 AU from the parent star. Moreover, an examination of data within the HST archives showed that the outer three planets were detected on NICMOS observations taken in 1998, and careful re-analysis of those data, together with subsequent observations, by a team led by Remi Soummer has resulted in strong constraints on the orbital parameters. Mid-infrared observations with Spitzer have revealed complex debris disk structure. Program GO 12281 aims to detect scattered light from the planetary disk structure through observations with the STIS coronagraph.

GO 12582: Probing the explosion environment and origin of Type Ia supernovae


Supernova in M101
Supernovae have long attracted the attention of both amateur and professional astronomers as a means of studying the violent eruption and death of massive stars and degenerates. However, in the last decade they have also acquired considerable importance as distance indicators, tracing the expansion of the universe to redshifts well beyond the reach of more conventional yardsticks, such as cepheids, and providing a key underpinning for the hypothesised existcen of dark energy. Understanding the supernovae themselves, and, in particular, their progenitors, is key to accurately interpreting their luminosities and distances. The present program aims to tackle that aspect of the problem by using WFC3-UVIS and STIS to obtain deep UV-imaging and spectroscopy of Type Ia SNe occuring within the (relatively - z<0.05) local universe. The supernovae will eb chosen to span a range of dust obscuration/reddening, offering the prospect of detecting and characterising the 2175-Angstrom absorption feature in a range of systems. The UV data will also provide a means of investigating the stellar populations within the immediate vicinity of the SNe, and hence potentially provide some constraints on the progenitor. The present observations have beent riggered to observe SN2012CG in NGC 4424.

GO 12915: Proper motions of isolated massive stars near the Galactic Center


NICMOS images of the Arches and Qunituple clusters near the Galactic Centre
The Galactic Centre lies in the heart of the constellation of Sagittarius, and at a distance of ~8 kiloparsecs from the Sun. Galactic nuclei are the likely end-point for mass accretion, and are generally the site of highly energetic activity; the Galactic Centre is no exception. Ground-based adaptive optics near-infrared imaging has resolved a number of stars within the core, close to the compact radio source Sagittarius A*. Monitoring of those sources over the last decade has shown that they are in rapid orbital motion around a very massive central object, now clearly identified as a ~3 million solar-mass black hole. Moving beyond the core, to distances of tens of parsecs from centre, observations have revealed molecular gas, several young, massive star forming regions and ~40 massive Wolf-Rayet stars dispersed through the region, beyond the clusters. The aim of the present proposal is to use the WFC3-IR camera to survey the central ~150 square arminutes at multiple epochs, allowing measurement of the proper motions of those isolated stars, and, potentially, determination of the place(s) of origin.

GO 13021: Revealing the Diversity of Super-Earth Atmospheres


Artist's impression of a planet in the GJ 1214 system
GJ 1214 is a 14th magnitude M4.5 dwarf that lies at a distance of ~13 parsecs from the Sun in the constellation of Ophiuchus. It's main claim to fame is that it has a confirmed planetary companion in an orbit with a period of 1.58 days and a mass of 6.55+/-0.98 earth masses. This super-Earth transits the parent star, allowing an accurate determination of its diameter as 2.64 times that of Earth. Transiting systems offer a potential gold-mine for extrasolar planetary studies, since not only is the diameter (and hence the average density) directly measureable form the eclipse depth, but 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. The present program will use the WFC3/IR grisms to map the near-IR spectral energy distribution through several trasnits, searching for characteristic features due to water and (perhaps) methane.

Past weeks:
page by Neill Reid, updated 8/10/2012
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