0 Assigned ID: 718 ----- Attempting Submission 1 (Fri Apr 07 18:34:13 GMT 2017) ----- 2017-09-13: I now constrained the ORIENT to a single value which should maximize the separation between the spectrum of the primary and that of the companion, and allows enough flexibility for scheduling (about a month). 2017-09-12: I resubmit following the comments from the CS, and I changed ORIENT to allow for a better result and an earlier and larger scheduling window. I have chosen only one of the two possible orientations of the observations as this is the closest in time possible. If the program is not schedulable in the first observing window I would like to modify this parameter. Still applicable (2017-07-20) -1444075614 ----- Attempting Submission 1 (Thu Jul 20 12:11:45 GMT 2017) ----- ----- Attempting Submission 2 (Tue Sep 12 10:42:03 GMT 2017) ----- HST Phase II Proposal 15079 (cscha_comp_wfc3_phase2_RESUBM.pdf.apt) successfully submitted. Receipt: # 15079-2 ----- Attempting Submission 3 (Wed Sep 13 07:50:41 GMT 2017) ----- Direct high-contrast imaging has discovered a number of substellar companions to date. Most of them are located at large separations of 10s or 100s of au. The formation of such massive objects with several Jupiter masses at the large distances at which they reside is not well understood by planet formation models. The formation timescales of such planets is much larger than the typical disk dissipation time. Most of the detected substellar companions are located in old, typically >10Myr, systems where we can only study the remnants of the circumstellar disks in the form of debris belts. We detected for the first time a planet in a young (2 Myr) system right outside of a dust and gas rich circumbinary disk, which we also resolve in (polarized) scattered light using the extreme adaptive optics Imager SPHERE at the ESO Very Large Telescope. We already confirmed that the object is co-moving with the primary star and now ask for follow up spectroscopy with the sole instrument capable of it, HST/WFC3, to firmly derive its mass. The aim of the proposal is to obtain a spectrum with the WFC3/IR G141 grism of a newly discovered planetary mass object located outside the circumplanetary disk of the CS Cha system. Observing strategy: The companion is located at 1.32 arcsec from the central system, and at a position angle of 261.69 degrees. The central system is much brighter than the target (J=9 mag and J=19 mag, respectively) thus the observations are challenging. We cannot observe both targets simultaneously since the contrast of WFC3/IR is not enough, therefore we must put the central bright system outside the field of view, and position the companion in the cross-dispersion direction at the inner edge of the detector. We have thus given as coordinates for the target an offset position. Studies have shown that the width of the cross-dispersion profile ranges from about 1.3 to 1.6 pixel (FWHM) with the G141 grism. Even if the spectrum of the bright target will appear in the detector, we will anyway be able to separate the two spectra thanks to the high spatial resolution of WFC3. To position the object in the cross-dispersion direction we must have an orientation of ca. 40-60 degrees, or ca. 210-230 degrees. We specified only the latter as this is the inclination available at the next observation window. If not schedulable in October, we would like to specify 40-60 degrees, but then we have to change the pointing. Exposure time and orbit planning: The target is known to be a very low mass object, with spectral type later than M9.5, and with J=19 mag. We have performed ETC calculation using the G141 grism and we obtain a S/N=10 at 1.4micron, the minimum requirement, in 200s, while a more reliable S/N=30 with an exposure of 1330s. Furthermore, we must perform a direct image of the target, possibly at each dither position. We thus plan to perform a default two dither positions pattern with a sequence of one short (150s) image, and one spectrum exposed for 1350s at each dither position. Including overheads, this pattern will fit into one 60 minutes orbit, which is the estimated orbital visibility reported by the APT for this target. Planets and Planet Formation 6 false false false false false false SUPPORTED STAR PRE-MAIN SEQUENCE STAR T TAURI STAR This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/IR Spectroscopic No No G141 1505288948830 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 15079 :visit-id "01" :proposal-version -1 :trans-version "20170613" :date "13-Sep-2017 09:49:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 835616 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 15079 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 15079 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3198 :al-overhead-at-end 0 :internal-dur-at-end 595 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3579 :pcs-gap 0 ) false 1 0