0 Assigned ID: 1210 ----- Attempting Submission 1 (Tue Sep 29 21:05:11 GMT 2020) ----- HST Phase I Proposal 1210 successfully submitted. Receipt: # 1210-1 ----- Attempting Submission 2 (Wed Sep 30 10:29:07 GMT 2020) ----- HST Phase I Proposal 1210 successfully submitted. Receipt: # 1210-2 ----- Attempting Submission 3 (Wed Sep 30 15:47:32 GMT 2020) ----- HST Phase I Proposal 1210 successfully submitted. Receipt: # 1210-3 ----- Attempting Submission 4 (Wed Sep 30 16:59:05 GMT 2020) ----- HST Phase I Proposal 1210 successfully submitted. Receipt: # 1210-4 Due to a limitation of APT caused by the exoplanet's orbital period being less than 1 day, we have, in co-ordination with our Contact Scientist Peter McCullough, doubled the period of the target to avoid this warning. The phase constraints have been adjusted to compensate for this. 252609490 ----- Attempting Submission 1 (Sat Nov 28 11:11:20 GMT 2020) ----- HST Phase II Proposal 16457 successfully submitted. Receipt: # 16457-1 ----- Attempting Submission 2 (Mon Nov 30 18:35:58 GMT 2020) ----- ----- Attempting Submission 3 (Fri Dec 18 15:45:33 GMT 2020) ----- We propose to use the G102 (0.8 - 1.1 microns) and G141 (1.1 - 1.65 microns) grisms of Hubble's Wide Field Camera 3 (WFC3) to study an ultra-hot Neptune. Given its size and orbital period, it is an intriguing target for atmospheric characterisation as it is unclear how the planet has managed to maintain its H/He envelope. These Hubble observations will have the capability to unveil the composition of this atmosphere, constraining the metallicity and thus providing insights into its formation history, as well as being able provide initial measurements of the mass loss for this planet via the helium triplet at 1.083 microns. We will acquire two transits, one utilising the G102 grism while the other shall use G141. The observations will be made in slitless spectroscopic mode and use spatial scans. We will take both forward and reverse scans with 9 sets of scans per orbit. In orbits two, three and four of each visit, we will take an additional forward scan to maximise the duty cycle. In orbit one, a direct image will be taken for calibration purposes. For both visits, our spatial scans shall have a rate of 0.18 arcseconds/second. We will use the SPARS10 sequence with 15 samples per integration. We will read out a subarray with a size of 256 pixels. Individual exposure times will be 103.1 sec, resulting in a scan across 18.6 arcsecs which is equivalent to 143 pixels per exposure. Such an observational strategy leave plenty of additional pixels for estimating the background flux. The first orbit will be discarded, which is a standard procedure adopted by all HST transiting exoplanet observations, as the data shows greater systematics due to the thermal settling of the telescope. The remaining orbits will provide good phase coverage during transit, and allow for sufficient time (2 HST orbits - one before transit, one after transit) to establish the baseline stellar flux necessary to accurately measure the transit depth. Note that we used TWICE the orbital period as a work around to schedule the observations due to a limitation of APT caused by the exoplanet's orbital period being less than 1 day. The true orbital period of the planet is half of that listed in this proposal for scheduling purposes. We also adjust the phase of the first exposure accordingly (see comment to Visit 01). Dr. Billy Edwards has substantial experience in characterising exoplanetary atmospheres through transit spectroscopy with space-based telescopes. He is the project scientist of the Twinkle space telescope and is leading the scientific performance modelling for the mission. Additionally, he leads studies into the potential targets for the ESA M4 Ariel mission and works on ensuring the mission meets the science requirements and the scientific yield is maximised. He is proficient in analysing Hubble WFC3 data, the current state-of-the-art from space, to recover atmospheric signatures. Miss Lara Ainsman is a PhD student at University College London whose research focuses on the capabilities of infrared space-based telescopes to study the atmospheres of exoplanets. She has experience using Hubble data, leading a research study of the highly eccentric planet WASP-117 b. Additionally, she works on the potential of studying exoplanets with the next generation of facilites. Mr Quentin Changeat is prominent researcher in exoplanet atmospheric retrieval studies. He contributes to the ESA Ariel mission and performs retrieval simulations to investigate biases in analysing telescope data. He also has a strong experience in analyzing current exoplanet data from the HST WFC3 in both transit and eclipse spectroscopy. More recently he took part in the complete rebuild of the TauREx 3 retrieval suite and works in implementing the necessary features to analyse current and future exoplanet atmosphere data. Mr Kai Hou Yip has extensive knowledge of using data from Hubble WFC3 having developed a new methodology for analyzing transmission spectra by using the light curves in the atmopsheric fitting process. He has also pioneered a novel technique for finding exoplanets with Hubble data using machine learning and has led a study seeking to explore the compatibility between VLT and Hubble data. Prof. Giovanna Tinetti is the P.I. of the ESA-M4 mission, Ariel, and the European Research Council ExoLights project at UCL, focusing on observations and interpretation of exoplanet atmospheres. Her experience in exoplanet science and management of large teams is demonstrated by being the P.I. of two proposed ESA-M missions (M4, ARIEL, and M3, EChO) both dedicated to exoplanet spectroscopy. She has received Institute of Physics and NASA awards for pioneering work in IR spectroscopy of exoplanets. Exoplanets and Exoplanet Formation 0 false false false false true false false SUPPORTED STAR EXTRA-SOLAR PLANET This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 WFC3/IR Spectroscopic No No G102 WFC3/IR Spectroscopic No No G141 1619194304706 The scheduling data was generated by CASM 28.2. CASM was run in Phase II mode. /private/var/folders/58/m3km1yk15rgcq0hfq011tfk80002ks/T/OPVisit11959313611846508481.xml The orbital period of the exoplanet is less than 1 day, which cause a problem for HST scheduling software in APT. It claims in the Visit Planner, "Phase windows are not calculated when the gap between schedulable intervals is less than 1 days (sic), assuming no scheduling restrictions for constrain Phase 0.806 / 0.814" but if that's really what the HST scheduling software will do (as opposed to the APT simulation of that), then we need to work around this. The simplest work around is to double the period so THAT is longer than 1 day. But if we double the period we have to adjust the phase constraint accordingly - make it 2x closer to unity. So instead of Period = 0.7920638416243817 d and phase = 0.806/0.814 we use 1.58412748 d and 0.903/0.907. We do this for both visits. So as to not reduce the number of available scheduling windows, we have offset the zero phase of visit 2 from visit 1 by 0.7920638416243817 d days so that visit 1 utilises scheduling opportunities 1,3,5... and visit 2 options 2,4,6 etc. (Tic-Visit :proposal-id 16457 :visit-id "01" :proposal-version -1 :trans-version "20200619" :date "23-Apr-2021 12:11:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1309488 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16457 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16457 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2486 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2414 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2414 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2414 :al-overhead-at-end 0 :internal-dur-at-end 436 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) true 4 0 1608305373688 The scheduling data was generated by CASM 28.2. CASM was run in Phase II mode. See comment to Visit 01 ! It applies equally to Visit 02. (Tic-Visit :proposal-id 16457 :visit-id "02" :proposal-version -1 :trans-version "20200619" :date "18-Dec-2020 15:29:29.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1443920 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16457 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16457 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2628 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16457 :visit-id "02" :orbit-number 4 :pcs-time 392 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 457 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3145 :pcs-gap 0 ) false 4 0