scholarly journals Surveying the Solar Neighborhood for Brown Dwarf Companions with the ECLIPSE Discovery Mission

2003 ◽  
Vol 211 ◽  
pp. 523-524
Author(s):  
Karl Stapelfeldt
Keyword(s):  
Luminosity Function ◽  
Hubble Space Telescope ◽  
Scattered Light ◽  
Solar Neighborhood ◽  
Brown Dwarf ◽  
Space Telescope ◽  
Effective Temperatures

The proposed Eclipse Discovery mission is an optical space telescope designed to provide a thousandfold reduction in scattered light near bright stars in comparison to any Hubble Space Telescope instrument. A survey of 500 single stars within 15 pc can detect companions with absolute z magnitude of 22 at separations > 10 AU in most of the targets. Spectrophotometry of CH4 and H2O bands between 0.8-1.0 μm can be used to derive the effective temperatures of the objects. The ECLIPSE brown dwarf survey would directly measure the luminosity function of brown dwarf companions down to ~20 Jupiter masses, providing a crucial comparison with field objects.

scholarly journals The HST large programme on NGC 6752 – III. Detection of the peak of the white dwarf luminosity function

2019 ◽  
Vol 488 (3) ◽  
pp. 3857-3865
Author(s):  
L R Bedin ◽  
M Salaris ◽  
J Anderson ◽  
M Libralato ◽  
D Apai ◽  
...  
Keyword(s):  
Globular Cluster ◽  
White Dwarf ◽  
Luminosity Function ◽  
Main Sequence ◽  
Hubble Space Telescope ◽  
Horizontal Branch ◽  
Space Telescope

ABSTRACT We report on the white dwarf (WD) cooling sequence of the old globular cluster NGC 6752, which is chemically complex and hosts a blue horizontal branch. This is one of the last globular cluster WD cooling sequences accessible to imaging by the Hubble Space Telescope. Our photometry and completeness tests show that we have reached the peak of the luminosity function of the WD cooling sequence, at a magnitude mF606W  = 29.4 ± 0.1, which is consistent with a formal age of ∼14 Gyr. This age is also consistent with the age from fits to the main-sequence turn-off (13–14 Gyr), reinforcing our conclusion that we observe the expected accumulation of WDs along the cooling sequence.

scholarly journals Photometric Characteristics of Data from the Hubble Space Telescope Goddard-High Resolution Spectrograph

1988 ◽  
Vol 132 ◽  
pp. 35-38
Author(s):  
Dennis C. Ebbets ◽  
Sara R. Heap ◽  
Don J. Lindler
Keyword(s):  
Exposure Time ◽  
Hubble Space Telescope ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Signal To Noise ◽  
Space Telescope ◽  
Additional Noise ◽  
Reduction Strategies ◽  
Noise Ratio

The G-HRS is one of four axial scientific instruments which will fly aboard the Hubble Space Telescope (ref 1,2). It will produce spectroscopic observations in the 1050 A ≤ λ ≤ 3300 A region with greater spectral, spatial and temporal resolution than has been possible with previous space-based instruments. Five first order diffraction gratings and one Echelle provide three modes of spectroscopic operation with resolving powers of R = λ/ΔΔ = 2000, 20000 and 90000. Two magnetically focused, pulse-counting digicon detectors, which differ only in the nature of their photocathodes, produce data whose photometric quality is usually determined by statistical noise in the signal (ref 3). Under ideal circumstances the signal to noise ratio increases as the square root of the exposure time. For some observations detector dark count, instrumental scattered light or granularity in the pixel to pixel sensitivity will cause additional noise. The signal to noise ratio of the net spectrum will then depend on several parameters, and will increase more slowly with exposure time. We have analyzed data from the ground based calibration programs, and have developed a theoretical model of the HRS performance (ref 4). Our results allow observing and data reduction strategies to be optimized when factors other than photon statistics influence the photometric quality of the data.

scholarly journals Hubble Space Telescope Imaging of the Disks and Jets of Taurus Young Stellar Objects

1997 ◽  
Vol 182 ◽  
pp. 355-364 ◽  
Author(s):  
Karl Stapelfeldt ◽  
Christopher J. Burrows ◽  
John E. Krist ◽  
Keyword(s):  
High Spatial Resolution ◽  
Hubble Space Telescope ◽  
Scattered Light ◽  
Young Stellar Objects ◽  
Opening Angle ◽  
Stellar Objects ◽  
Space Telescope ◽  
Spread Function ◽  
Large Opening ◽  
T Tau

We report on Hubble Space Telescope imaging of eleven young stellar objects in the nearby Taurus molecular clouds. The high spatial resolution and stable point spread function of HST reveal important new details of the circumstellar nebulosity of these objects. Three sources (HH 30, FS Tau B, and DG Tau B) are resolved as compact bipolar nebulae without a directly visible star. In all three cases, jet widths near the sources are found to be 50 AU or less. Flattened disk structures are seen in absorption in HH 30 and FS Tau B, and in reflection about GM Aur. Extended envelope structures traced by scattered light are present in HL Tau, T Tau, DG Tau, and FS Tau. The jet in DG Tau exhibits a large opening angle and is already resolved into a bow-like structure less than 3″ from the star.

scholarly journals VERTICAL ATMOSPHERIC STRUCTURE IN A VARIABLE BROWN DWARF: PRESSURE-DEPENDENT PHASE SHIFTS IN SIMULTANEOUS HUBBLE SPACE TELESCOPE - SPITZER LIGHT CURVES

2012 ◽  
Vol 760 (2) ◽  
pp. L31 ◽  
Author(s):  
Esther Buenzli ◽  
Dániel Apai ◽  
Caroline V. Morley ◽  
Davin Flateau ◽  
Adam P. Showman ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Phase Shifts ◽  
Light Curves ◽  
Brown Dwarf ◽  
Space Telescope ◽  
Atmospheric Structure

scholarly journals The Y dwarf population with HST: unlocking the secrets of our coolest neighbours – I. Overview and first astrometric results

2020 ◽  
Vol 501 (1) ◽  
pp. 911-915
Author(s):  
C Fontanive ◽  
L R Bedin ◽  
D C Bardalez Gagliuffi
Keyword(s):  
Proper Motion ◽  
Hubble Space Telescope ◽  
Proper Motions ◽  
Brown Dwarf ◽  
Space Telescope ◽  
First Results

ABSTRACT In this paper, we present our project that aims at determining accurate distances and proper motions for the Y brown dwarf population using the Hubble Space Telescope. We validate the program with our first results, using a single new epoch of observations of the Y0pec dwarf WISE J163940.83−684738.6. These new data allowed us to refine its proper motion and improve the accuracy of its parallax by a factor of three compared to previous determinations, now constrained to ϖ = 211.11 ± 0.56 mas. This newly derived absolute parallax corresponds to a distance of 4.737 ± 0.013 pc, an exquisite and unprecedented precision for faint ultracool Y dwarfs.

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