0 Assigned ID: 656 ----- Attempting Submission 1 (Fri Apr 05 19:20:18 GMT 2019) ----- FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser Added dithers to the observations, removed the CR-SPLIT. 2051171239 ----- Attempting Submission 1 (Tue Jul 23 19:30:44 GMT 2019) ----- ----- Attempting Submission 2 (Sat Oct 12 04:44:35 GMT 2019) ----- We aren't sure if we will need post-flash because the background levels may be quite high. Luminous blue variables (LBVs) are evolved massive stars that undergo dramatic mass loss and irregular variability. Whether LBVs originate from a single massive progenitor or through binary interaction is still debated. They statistically prefer isolated locations in star forming galaxies, far away from O-type stars, which indicates a likely binary origin. Located in a young stellar cluster, the newly discovered LBV outburst MCA1-B in M33 affords us the rare opportunity to independently age-date an LBV based on the ages of the other cluster members. By determining the cluster turn off mass we can ascertain if the LBV is overluminous compared to the rest of the cluster, and therefore determine decisively if it has been rejuvenated through binary evolution. If it does appear to be younger than the surrounding population, we can determine quantitatively how much mass it has gained or what the likely masses of the merger components were. Only now while the LBV is in a fainter, quiescent phase and only with the UV sensitivity and spatial resolution of WFC3 can we get the UV-to-optical imaging needed to create accurate color-magnitude diagrams of the LBV's host cluster in order to age-date MCA1-B. The LBV eruption of MCA-1B was also unusually hot at peak, which may be linked to its low-metallicity environment in the outskirts of M33; this may provide critical clues about the physical LBV instability. The observations are all set up in one visit of two orbits, but these orbits can be separated as need be. The object(s) of interest are bright enough to likely not need post-flash, but please advise if this should be added. There are no special orients needed, although we would prefer both orbits taken at the same orient if they need to separated into separate visits. We are using full frame instead of sub-array because we need the whole nearby stellar population. Both J. Andrews and N. Smith are experts in massive stars and their post-MS evolution. J. Andrews has a background in stellar populations, particularly with HST in the UV. N. Smith has written dozens of papers on LBVs and SN imposters, with particular emphasis on the ellusive LBV Eta Car. He has also pioneered the work on the isolation of LBVs and their likely blue-straggler status. Both investigators have extensive experience in the reduction and analysis of HST data. Stellar Physics Stellar Populations 6 false false false false false false false SUPPORTED STELLAR CLUSTER OB ASSOCIATION OPEN CLUSTER YOUNG ASSOCIATION NO J2000 J2000 WFC3/UVIS Imaging No No F225W WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.145 LINE false false 2 46.84 WFC3-UVIS-DITHER-LINE 1 false 1570855340551 /private/var/folders/fk/5q2b4ncs2n5404rs9p1t23g00000gn/T/OPVisit9856190543366621617.xml The scheduling data was generated by CASM 27.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15855 :visit-id "01" :proposal-version -1 :trans-version "20190514" :date "11-Oct-2019 21:42:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2887456 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15855 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15855 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2847 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) (Tic-Orbit :proposal-id 15855 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2877 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3180 :pcs-gap 0 ) true 2 0