This Echo is READ ONLY !   NO Un-Authorized Messages Please!
 ~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

7 Apr 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT       # 3335

PERIOD COVERED: DOYs 94-96

Part 3 of 4

STIS 9437

Quantitative Constraints for Massive Star Evolution Models with
Rotation 

Rotation is now recognized as an important physical component in
understanding massive stars. Theory suggests that rotation affects
the lifetimes, chemical yields, stellar evolution tracks, and the
supernova and compact remnant properties {Heger & Langer 2000,
Maeder & Meynet 2000}. In a Cycle 7 program, we proved that
rotational mixing occurs in massive main sequence stars {Venn et al.
2001}. In this proposal, we want to quantitatively test model
predictions and constrain the theory for a better understanding of
massive star evolution. We are requesting HST STIS observations of
the BIII 2066 Angstrom resonance line of seven massive stars in three
young clusters carefully selected from IUE analyses. These stars show
traces of boron depletion, but without nitrogen enrichment; rotation
is the only theory able to explain this abundance pattern. These new
abundances will allow us to test rotating model predictions: that
mixing strength increases with stellar age, mass, and rotation rate.
They will also help to quantitatively constrain the rotational mixing
efficiencies in massive stars. One very high S/N spectrum of a
moderately boron-depleted star is also requested. We wish to measure
its 11B/10B ratio, which is predicted to change as boron is depleted
in the rotating models. This ratio will further confirm rotational
effects and observationally constrain the 10B{p, Alpha} thermonuclear
reaction rate, which is presently highly uncertain. 

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

This is the default archival pure parallel program for STIS during
cycle 10. 

STIS 9620

STIS Sparse Field CTE test-internal {Cycle 11}

CTE measurements are made using the "internal sparse field test",
along the parallel axis. The new "POS=" optional parameter is used to
provide off-center MSM positionings of some slits. All exposures are
internals. 

STIS 9505

The Evolution of Molecular Clouds.

The combined STIS, FUSE and ground-based results will yield
information needed to understand the role of ablation in the
evolution of the central clouds. 
STIS/MA2 9465

The Cosmic Carbon Budget

Gaseous carbon drives the chemistry of, and is an important coolant
in interstellar clouds. In solid form, carbon is the second most
abundant element in interstellar dust, the key element contributing
to interstellar extinction, and the dominant heat source in some
interstellar clouds. Given the fundamental importance of this element
to interstellar cloud physics, it is surprising that only 8
measurements of gas- phase carbon abundances exist for neutral
clouds; 7 are in diffuse clouds where the least amount of chemistry
and dust incorporation are expected. The single measurement in a
translucent cloud suggests a C abundance that differs from the
diffuse clouds, but the measurement uncertainties make this
difference statistically insignificant. We, therefore, have no
information about carbon's behavior in translucent clouds, regions
dense enough for chemistry and dust growth to be important but low
enough extinction so that UV spectroscopy is possible {unlike for
molecular clouds}. We propose to measure total gas-phase C abundances
in 6 translucent clouds with our principal scientific goals being to
1} accurately determine the fraction of carbon in the gas and dust
phases in environments bridging the gap between diffuse and molecular
clouds 2} determine the relative depletions of C and O in neutral
clouds with known O-depletion enhancements and 3} explore how the
interstellar gas-phase C/H is related to extinction variations.

WF/PC-2 9102

A YSO-Like Pulsed Astrophysical Jet And Bipolar Nebula In A Dying
Star: WFPC2/STIS Study Of He2-90.

The WF/PC-2 was used to observe an extended, highly-collimated,
bipolar jet in He2-90, an object long classified as a planetary
nebula {PN}. Recently-discovered images show that the morphology of
He2-90 does not look like that of any known PN, but resembles that of
a classical young stellar object {YSO}. Observations will determine
the speed of the jet {only slightly inclined to the sky plane}
through proper motion observations of the knots in the jet: An
H-alpha image will be obtained for comparison with the Sep99
discovery image. It is crucial to observe the velocity field of the
flow at the highest spatial- resolution, as close as possible to the
origin of the jet in order to constrain theories for how the jet is
driven, and the nature of the central object. 

WFPC2 9710

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

WFPC2 9676

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure
Parallel program. The program will be used to take parallel images of
random areas of the sky, following the recommendations of the 2002
Parallels Working Group. 

WFPC2 9594

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt2/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels. 

FLIGHT OPERATIONS SUMMARY:

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

 - Continued -

@Message posted automagically by IMTHINGS POST 1.30
---