This week on HST

HST Programs: September 14 - September 20, 2009

Program Number Principal Investigator Program Title Links
11142 Lin Yan, California Institute of Technology Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3 Abstract
11213 Gerard T. van Belle, California Institute of Technology Distances to Eclipsing M Dwarf Binaries Abstract
11359 Robert W. O'Connell, The University of Virginia Panchromatic WFC3 survey of galaxies at intermediate z: Early Release Science program for Wide Field Camera 3. Abstract
11559 Imke de Pater, University of California - Berkeley Jovian Upheaval and its Impact on Vortices Abstract
11594 John M. O'Meara, Saint Michaels College A WFC3 Grism Survey for Lyman limit absorption at z=2 Abstract
11600 Benjamin Weiner, University of Arizona Star formation, extinction and metallicity at 0.7 Abstract
11650 William M. Grundy, Lowell Observatory Mutual Orbits, Colors, Masses, and Bulk Densities of 3 Cold Classical Transneptunian Binaries Abstract
11657 Letizia Stanghellini, National Optical Astronomy Observatories The population of compact planetary nebulae in the Galactic Disk Abstract
11670 Peter Garnavich, University of Notre Dame The Host Environments of Type Ia Supernovae in the SDSS Survey Abstract
11673 Alain Lecavelier des Etangs, CNRS, Institut d'Astrophysique de Paris Dynamics in the atmosphere of the evaporating planet HD189733b Abstract
11704 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale Abstract
11788 George Fritz Benedict, University of Texas at Austin The Architecture of Exoplanetary Systems Abstract
11789 George Fritz Benedict, University of Texas at Austin An Astrometric Calibration of Population II Distance Indicators Abstract
11998 Karen J. Meech, University of Hawaii Determining the Rotational Phase of Comet 9P/Tempel 1 in Support of the StardustNExT Mission Abstract

Selected highlights

GO 11213: Distances to Eclipsing M Dwarf Binaries

Artist's impression of a cool binary system Eclipsing binaries are stellar systems where the orbital plane lies in the line of sight, leading to the components undergoing mutual eclipses. These systems are extremely powerful probes of stellar properties, since (given the appropriate radial velocity measurements) they permit direct measurement of both stellar masses and radii. Accurate distances can also be derived from these systems. These results are particularly interesting for stars near the bottom of the main sequence, approaching the hydrogen buyrning limit. The present program aims to use the Fine Guidance Sensors on HST to determine sub-milliarcsecond trigonometric parallaxes for five M-dwarf binaries: YY Gem, GU Boo, CM Dra, NSVS0103 and TRES-HER0-R

GO 11359: Panchromatic WFC3 survey of galaxies at intermediate z: Early Release Science program for Wide Field Camera 3.

HST/ACS images of part of the GOODS field The Great Observatories Origins Deep Survey, is a large-scale program that is designed to probe galaxy formation and evolution at redshifts from z~1 to z~6. GOODS covers two ~150 sq. arcminute fields, one centred on the Hubble Deep Field and the second on the Chandra Deep Field South, and combines deep optical/far-red imaging (F435W, F606W, F775W and F850LP filters) using ACS on HST with deep IRAC (3.6 to 8 micron) and MIPS (25 micron) imaging with Spitzer. Chandra data are also available for the bulk of the field, and NICMOS data H-band (F160W) imaging, coupled with parallel ultraviolet observations using the ACS/SBC, were obtained for a subset of the area in a Cycle 16 contingency program. The present program will build on these observations by using Wide-Field Camera 3 to obtain ultraviolet and near-infrared imaging, and grism spectroscopy, covering ~30% of the GOODS (South) field. The goal is to probe star formation at intermediate redshifts (1 < z < 2).

GO 11673: Dynamics in the atmosphere of the evaporating planet HD189733b

Artist's conception of atmospheric ablation on a hot jupiter HD 189733 is an early K-type dwarf lying at a distance of ~19.3 parsecs in the constellation of Vulpecula. It has an M dwarf companion, HD 189733B, at a separation of ~220 AU, and also harbours a planetary system. Like ~3% of sun-like stars, it has a `hot Jupiter', HD 1897733b, orbiting orbiting the parent star at a distance of 0.031 AU in a period of 2.219 days. At these distances, the planetary atmosphere is heated to temperatures exceeding 1000K, and the expectation is that it will be subject to extensive evaporation. This is a transiting system, so the planetary mass is well determined as 1.13+/- 0.03 M, and both HST and SPitzer have been employed in probing the planetary atmosphere, either by searching for enhanced absorption during the primary eclipse (HD 189733b transits HD 189733), or by searching for reduced (mid-infrared) emission as HD 189733 eclipses the hot Jupiter. The present proposal aims to build on previous HST observations using the ACS/SBC prism. Those observations were sufficient to identify signatures of planetary evaporation, but of too low resolution to quantify the process. The present proposal will use COS to obtain higher resolution data, and examine the dynamics of the evaporation process.

GO 11998: Determining the Rotational Phase of Comet 9P/Tempel 1 in Support of the StardustNExT Mission

The expected view of Tempel 1 from Stardust in 2011; the red target marks the Deep Impact site NASA's Stardust mission was launched on February 7th 1999 with the prime aim of making a close fly-by of Comet Wild 2, collecting samples of cometary material, and returning them to Earth. Stardust duly performed the fly-by in january 20904, and then succeeded in returning the samples to Earth (albeit with a somewhat bumpy landing) in January 2006. And that seemed to concldue Stardust's mission. However, it was soon realised that there were other possibilities. Stardust has received a number of boosts from Eareth encounters over its career, and the current orbit is moderately elliptical, carrying it from a perihelion position inside Venus' orbit to beyond Mars. This puts Stardust in a positojn where it can follow up on another NASA Mission, Deep Impact. That mission targeted Comet Tempel 1 for a July 4th 2005 impact and fly-by; the aim was to use the impact to break open the comet and reveal its interior, and the parent Deep Impact probe duly acquired a series of spectacular images. Now Stardust, re-titled as Stardust-NExT, will have a much slower, and more extended, encounter with the comet in 2011. One of the crucial aspects of planning this mission is ensuring that the Deep Impact site will be visible during that encounter. Comets rotate, so this demands accurate measurement of Tempel I's rotation. Wide Field Camera 3 on HST is being used to monitor the comet photometrically; that monitoring will reveal small changes in brightness as different areas of the surface come into, and hence measure the rotation.

Past weeks:
page by Neill Reid, updated 23/9/2009