0
Assigned ID: 1202
----- Attempting Submission 1 (Fri Apr 07 23:57:23 GMT 2017) -----
Updated timing windows to account for the HST down time in 2018.
-1113343222
----- Attempting Submission 1 (Mon Jul 17 03:58:30 GMT 2017) -----
----- Attempting Submission 2 (Thu Aug 09 19:55:08 GMT 2018) -----
----- Attempting Submission 3 (Thu Nov 08 01:14:38 GMT 2018) -----
The Coolest Sample of Brown Dwarf Dynamical Masses
We propose a 3-year orbit monitoring program to measure the first dynamical masses for brown dwarfs below 1100 K. With projected separations of only 1-2 AU, our targets are among the tightest substellar visual binaries ever found and are amenable to orbit determinations within only a few years. When combined with our parallax determinations, these data will yield dynamical masses with <10% uncertainties. Our targets have been discovered at the limits of existing facilities and thus promise to be the only viable objects in this temperature regime (350-1000 K) for direct mass measurements during the JWST era.
The goal of our observations is to obtain precise relative astrometry (~3-5 mas) for six brown dwarf binaries. Our data spanning 3 cycles will allow us to determine their orbits and thereby measure their dynamical masses. ACS/WFC enables a finer pixel scale than WFC3/IR and better sensitivity than WFC3/UVIS, both of which (high SNR, and better deblending of our tight 0.07"-0.11" binaries) are key to achieving our science goals.
We use a standard 3-position dither sequence to guard against cosmic rays and to sample different parts of the detector in case our target lands on a bad pixel in a single pointing. We set the exposure times to fill the time available in each visit, which will yield SNR of ~30 for our faintest target (WISE0146, J=20.7) and will still be far from saturating any other of our sources in F850LP (the brightest is J=16.4).
Stellar Physics
Planets and Planet Formation
6
false
false
false
false
false
false
false
SUPPORTED
STAR
BROWN DWARF
T
J2000
J2000
J=20.7 mag
STAR
BROWN DWARF
T
J2000
J2000
J=18.2 mag
STAR
BROWN DWARF
T
J2000
J2000
J=17.1 mag
STAR
BROWN DWARF
T
J2000
J2000
z'(AB)=23.6 mag, J=19.7 mag
STAR
BROWN DWARF
T
J2000
J2000
J=16.4 mag
STAR
BROWN DWARF
T
J2000
J2000
J=16.9 mag
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
ACS/WFC
Imaging
No
No
F850LP
POS-TARG
DITHER
3.011
LINE
false
false
3
85.28
ACS-WFC-DITHER-LINE
1
false
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