Status Report

NASA Hubble Space Telescope Daily Report #4780

By SpaceRef Editor
January 29, 2009
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Continuing to collect World Class Science

PERIOD COVERED: 5am January 28 – 5am January 29, 2009 (DOY 029/1000z-030/1000z)


WFPC2 11316

HST Cycle 16 & Pre-SM4 Optical Monitor

This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor, 11020. Please see that proposal for a more complete description of the observing strategy. The 6 visits comprising this proposal observe two single standard stars with WFPC2/PC in order to establish overall OTA focal length for the purposes of focus maintenance. The goal of this monitoring before SM4 is to establish a best estimate of the OTA focus entering SMOV.

WFPC2 11944

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint to observe using ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass – radius relation.

WFPC2 11962

A New Supernova in the Antennae; Narrowing in on the Hubble Constant and Dark Energy

A measurement of the Hubble constant to a precision of a few percent would be a powerful aid to the investigation of the nature of dark energy and a potent “end-to-end” test of the present cosmological model. In Cycle 15 we constructed a new, streamlined distance ladder utilizing high-quality type Ia supernova data and observations of Cepheids with HST in the near-IR to minimize the dominant sources of systematic uncertainty in past measurements of the Hubble constant and reduce its total uncertainty to a little under 5%. Here we propose to exploit this new route with a rare opportunity to begin reducing the remaining uncertainty. SN 2007sr in the Antennae (NGC 4038/9) is the rare SN Ia which is suitable for increasing the precision of small calibration sample of SNe Ia. Even rarer is that it is close enough that it’s Cepheids are within range of observing with WFPC2 (and NICMOS, should it return to life). But we need to act fast as the window of long visibility and fixed orient runs from mid-early December 2008 to early March 2009. We request 34 orbits with WFPC2 to find the Cepheids in the SN host. We also request 16 orbits to observe the Cepheids we find with Camera 2, F160W if NICMOS becomes available by April 2009 . (If NICMOS does not return we would forgo these observations and ask the TTRB to let us make them with our own WFC3-IR allocation, though we much prefer the smaller pixel size of NIC2).

WFPC2 11966

The Recent Star Formation History of SINGS Galaxies

The Spitzer Legacy project SINGS provided a unique view of the current state of star formation and dust in a sample of galaxies of all Hubble types. This multi-wavelength view allowed the team to create current star formation diagnostics that are independent of the dust content and increased our understanding of the dust in galaxies. Even so, using the SINGS data alone we can only make rough estimates of the recent star formation history of these galaxies. The lack of high resolution observations (especially U-band and H-alpha) means that it is impossible to estimate the ages of young clusters. In addition, the low resolution of the Spitzer and ground-based observations means that what appear to be individual Spitzer sources can actually be composed of many individual clusters with varying ages. We need to know the ages, star formation histories, and extinction of these individual clusters to understand how these clusters form and age and thus influence the evolution of the galaxy. In this proposal we address this missing area of SINGS by obtaining high-resolution WFPC2 UBVI & H-alpha observations to not only accurately locate and determine the ages of the young stellar clusters in the actively star forming SINGS galaxies but to also address a variety of other scientific issues. Over 500 HST orbits and 500 hours of Spitzter observing time have been dedicated to observations of the SINGS sample. But the HST observations have not been systematic. By adding a relatively small fraction of this time for these requested observations, we will greatly enhance the legacy value of the SINGS observations by creating a uniform high resolution multi-wavelength HST archive that matches the quality of the lower resolution SINGS archive.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)



                         SCHEDULED      SUCCESSFUL

FGS GSacq                03                  03
FGS REacq                08                  08
OBAD with Maneuver       24                  24


SpaceRef staff editor.