Program Number | Principal Investigator | Program Title |
---|---|---|
13117 | Andrew J. Levan, The University of Warwick | A Chandra/HST survey of dark gamma-ray bursts and their hosts |
13288 | Amy Kathryn Furniss, Stanford University | PG 1424+240: Too Distant to be Seen? |
13297 | Giampaolo Piotto, Universita degli Studi di Padova | The HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation |
13305 | Carolin Villforth, University of St. Andrews | Do mergers matter? Testing AGN triggering mechanisms from Seyferts to Quasars |
13313 | Mederic Boquien, University of Cambridge | Determining attenuation laws down to the Lyman break in z~0.3 galaxies |
13315 | Marc W. Buie, Southwest Research Institute | Pluto Satellite Orbits in Support of New Horizons |
13319 | Alexandros Gianninas, The University of Oklahoma | COS Spectroscopy of Pulsating, Metal-Rich, Extremely Low Mass White Dwarfs |
13327 | Eileen T Meyer, Space Telescope Science Institute | Proper Motions at 500 Mpc: Measuring Superluminal motions in Optical Jets with HST |
13330 | Bradley M Peterson, The Ohio State University | Mapping the AGN Broad Line Region by Reverberation |
13335 | Adam Riess, The Johns Hopkins University | HST and Gaia, Light and Distance |
13352 | Matthew A. Malkan, University of California - Los Angeles | WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time |
13366 | Roelof S. de Jong, Leibniz-Institut fur Astrophysik Potsdam (AIP) | The vertical disk structure of spiral galaxies and the origin of their thick disks |
13383 | Mary E. Putman, Columbia University in the City of New York | Measuring the Properties of Dwarf Streams |
13393 | Dennis Zaritsky, University of Arizona | Galaxy Transformation in the Infall Regions of Clusters |
13410 | Cristina Pallanca, Universita di Bologna | COSMIC-LAB: a BSS orbiting a NS? The companion to the supermassive NS in NGC6440. |
13421 | Madelon C.P. Bours, The University of Warwick | CSS 41177: an eclipsing double white dwarf binary |
13429 | Margherita Giustini, European Space Agency - ESTEC | Unveiling the X-ray/UV Connection in AGN Winds: the PG 1126-041 Case Study |
13437 | Jane R. Rigby, NASA Goddard Space Flight Center | The Morphology and Star Formation Distribution in a Big Cool Spiral LIRG |
13452 | Matthew Hayes, Stockholm University | Coupling the emission of ionizing radiation and Lyman alpha |
13459 | Tommaso L. Treu, University of California - Santa Barbara | The Grism Lens-Amplified Survey from Space {GLASS} |
13473 | Timothy M. Heckman, The Johns Hopkins University | On the Nature of Highly Ionized Gas in the Halos of Normal Star-Forming Galaxies |
13482 | Britt Lundgren, University of Wisconsin - Madison | The Evolving Gas Content of Galaxy Halos: A Complete Census of MgII Absorption Line Host Galaxies at 0.7 < z < 2.5 |
13487 | Michael Salz, Universitat Hamburg, Hamburger Sternwarte | A pilot study to characterize the Lyman alpha emission of active exoplanet host stars |
13495 | Jennifer Lotz, Space Telescope Science Institute | HST Frontier Fields - Observations of Abell 2744 |
13613 | C. S. Kochanek, The Ohio State University | Dust to Dust: Monitoring the Evolution of the New Class of Self-Obscured Transients |
13629 | Yael Naze, Universite de Liege | Characterizing the high-energy properties of a highly magnetized star |
13632 | John T. Clarke, Boston University | Seasonal Dependence of the Escape of Martian Water |
GO 13297: The HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation
GO 13305: Do mergers matter? Testing AGN triggering mechanisms from Seyferts to Quasars
GO 13315: Pluto Satellite Orbits in Support of New Horizons
GO 13319: COS Spectroscopy of Pulsating, Metal-Rich, Extremely Low Mass White Dwarfs
The surface-temperature map on a pulsating white dwarf (Figure by Mike Montgomery U. Texas group) |
White dwarfs are compact, electron-degenerate remnants that represent the final evolutionary stage for stars less massive than ~7 Msun. White dwarfs emerge from planetary nebulae with extremely high surface temperatures, but with no central energy source, they simply cool like a brick. As they cool, the spectral energy distribution and the spectral characteristics evolve with time. Most white dwarfs have thin hydrogen envelopes, and are therefore have strong Balmer-series absorption lines in the optical at temperatures above ~8,000 degrees (DA white dwarfs), although a sizeable minority have helium envelopes and spectra dominated by helium lnes (DB white dwarfs). In most cases, the mass of the white dwarf scales with the mass of the progenitor, with typical masses around 0.6 MSun for 1-2 solar mass progenitors. A small number of white dwarfs, however, have much lower masases, closer to ~0.2 MSun. These extremely low-mass (ELM) white dwarfs are generally believed to have formed through binary evolution, with the envelope of the progenitor stripped through mass loss and companion accretion during the red giant phase, truncating evolution before the core could complete its growth. The present program aims to obtain COS UV spectra of two ELM white dwarfs, and has two goals in mind: first, some mdoels sugegst that these ELM white dwarfs are extremely metal-rich, and the COS observations will enable direct measurement of the atmospheric metallicity and determination whether these abundances are intrinsic or due to dust accretion; and, second, time-tag measurements with COS can be used to determine whether the degenerates are p-mode pulsators. |