0 Assigned ID: 1203 ----- Attempting Submission 1 (Fri Jan 17 02:00:10 GMT 2020) ----- HST Phase I Proposal 1203 (w178_midcycle27_v6_midcycle2_APT.apt) successfully submitted. Receipt: # 1203-1 0 ----- Attempting Submission 1 (Wed Mar 18 19:29:39 GMT 2020) ----- Comparing Escaping Metals and Heat Deposition in Ultra-hot Jupiters Ultra-hot Jupiters (UHJs), Jovian exoplanets with equilibrium temperatures greater than 2250 K, have quickly become recognized as unique laboratories for understanding the effect of irradiation on planetary atmospheres. To properly understand atmospheric heating and escape on exoplanets, we must observe how exoplanets respond to the irradiation they receive by measuring atmospheric mass loss and by detecting the opacity sources that determine the atmosphere's energy balance. We propose to observe the entire near-ultraviolet and optical transmission spectrum of a new high signal-to-noise ultra-hot Jupiter, WASP-178b. This planet shares many characteristics with the well-studied WASP-121b, but orbits the second hottest know exoplanet host star, allowing us to test the effects of host star irradiation spectrum on the atmosphere. By observing a transit in the UV at high spectral resolution with STIS/E230M, we will search for escaping metals, including Fe II and Mg II, and constrain the Roche lobe filling factor of the atmosphere. We can directly compare these results with recent observations of WASP-121b, providing insight into atmospheric escape mechanisms. We will also observe the entire NUV and optical transit spectrum at low spectral resolution with WFC3/UVIS/G280, allowing us to infer the presence of species like Fe, TiO, and VO while contributing necessary context to interpret the high resolution observations. This program will be the first comparative study of escaping metals and heat deposition in UHJs, some of the highest signal-to-noise exoplanet targets. All observations (STIS, COS, WFC3) observe an exoplanet transit or eclipse event. The spirit of exoplanet transit/eclipse observations is to attempt to gather as many spectra as possible before, during, and after a transit event with each image as identical as possible. As a transit observation consists of measuring a differential drop in stellar flux during the event, identical exposures are resistant to uncertainties in flat-fielding and very high photometric precisions are achievable. The STIS/E230M and WFC3/G280 observations require 5 orbit visits, as the baseline stellar flux and instrument systematics need to be measured before and after the transit/eclipse event, with the transit/eclipse event taking about 2.5 orbits orbits and is phase constrained to occur mid-way through the visit. Dr. Joshua Lothringer is an expert in modeling planetary and stellar atmospheres, especially ultra-hot Jupiters, and has additional expertise in retrieval analyses of exoplanet atmosphere data, as well as the analysis and reduction of HST/STIS data. Prof. David Sing has significant experience and expertise in the setup and reduction of HST observations. Prof. Sing is also an expert in exoplanet transit observations, leading many HST observing programs targeting transiting planets over the last 10 cycles. He has published 43 refereed papers over the last 12 years on HST-collected transiting exoplanet data. Prof. Sing has additional expertise in retrieval analyses of exoplanet atmosphere data. Dr. Panayotis Lavvas is an expert in modeling the upper atmospheres of exoplanets and escape processes. Dr. Nikolay Nikolov is an expert in analyzing HST exoplanet observations with extensive experience with HST/STIS and HST/WFC3. Dr. Kevin Stevenson is an expert in the analysis and observational setup of exoplanet observations with HST. Planets and Planet Formation 6 false false true false false false false AVAILABLE STAR A0-A3 V-IV EXTRA-SOLAR PLANET EXTRA-SOLAR PLANETARY SYSTEM NO Position and Proper motion from GAIA DR2 WASP-178 J2000 J2000 WFC3/UVIS Spectroscopic No No G280 STIS/NUV-MAMA Spectroscopic No No E230M 2707 The scheduling data was generated by CASM 28.0. CASM was run in Phase II mode. It is essential that all 5 orbits be scheduled in a continuous block. We have chosen WAVECAL=NO to avoid autowavecals at non-optimal times in the orbit and have scheduled wavecals manually, at the beginning of the visit and at the end of each orbit. (Tic-Visit :proposal-id 16086 :visit-id "01" :proposal-version -1 :trans-version "20191203" :date "18-Mar-2020 15:22:51.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 3375328 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16086 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16086 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2586 :al-overhead-at-end 81 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "01" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2926 :al-overhead-at-end 81 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "01" :orbit-number 3 :pcs-time 302 :si-vis-utilization 2926 :al-overhead-at-end 81 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "01" :orbit-number 4 :pcs-time 302 :si-vis-utilization 2926 :al-overhead-at-end 81 :internal-dur-at-end 132 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "01" :orbit-number 5 :pcs-time 302 :si-vis-utilization 2926 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) false 5 0 ETC gives saturation in 0.6 seconds. 0.3 seconds gives SNR 386. Auto-wavecal=NO, but we manually request wavecals at the beginning of the visit and then at the end of each orbit. Exposure time calculated to get 10 frames per orbit (except the first orbit because of target acq) to obtain enough time fidelity to model the systemics and transit time series'. This results in an SNR of ~15 per frame at 2707 angstrom. The scheduling data was generated by CASM 28.0. CASM was run in Phase II mode. The optional parameters SIZEAXIS1=2250 and SIZEAXIS2=590 are used for all exposures to minimize the data volume and hence time lost to buffer dumps. This is fine for the data that needs to be obtained because the spectum of WASP-178 will occupy only a narrow swath of pixel rows within the field. This also requires the use of optional parameters CENTERAXIS1 and CENTERAXIS2 in order to "steer" the location of the subarray readout so that it is centered on the target spectrum. If we were positioning on chip 1 we could set CENTERAXIS2=TARGET. However, for the field center (nominal "UVIS" aperture) location on chip 2, we cannot center the subarray on the target because this would cause the subarray to extend into the chip gap, so we hardwire CENTERAXIS1=2136 and CENTERAXIS2=1216, which is intended to put the vertical center of the subarray on the zeroth order of the target spectrum. Chip 2 biases are taken at the end of the visit because the grism exposures use custom subarrays, which will not have matching biases from the WFC3 bias calibration program. For each visit we have phase constraints around the event of the planetary transit, both the orbital period of the planet and the phasing needed are placed on the target acq exposure. To avoid any contamination by several dim, nearby stars, we have placed Orient Ranges for the observations to reach our science goals. This results in ~15 transit opportunities for the UVIS observations in the coming months. (Tic-Visit :proposal-id 16086 :visit-id "02" :proposal-version -1 :trans-version "20191203" :date "18-Mar-2020 15:22:57.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2754080 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16086 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16086 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2799 :al-overhead-at-end 66 :internal-dur-at-end 614 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "02" :orbit-number 2 :pcs-time 302 :si-vis-utilization 2928 :al-overhead-at-end 66 :internal-dur-at-end 638 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "02" :orbit-number 3 :pcs-time 302 :si-vis-utilization 2928 :al-overhead-at-end 66 :internal-dur-at-end 638 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "02" :orbit-number 4 :pcs-time 302 :si-vis-utilization 2928 :al-overhead-at-end 66 :internal-dur-at-end 638 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16086 :visit-id "02" :orbit-number 5 :pcs-time 302 :si-vis-utilization 2928 :al-overhead-at-end 66 :internal-dur-at-end 762 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3238 :pcs-gap 0 ) false 5 0 For target acq, saturation in 0.99 seconds. 0.5 seconds gives SNR of 391. Nominal "UVIS" aperture is ~10" above the chip gap on chip 1; a Y-postarg of about -50" places the target near the center of subarray on chip 2. SIZEAXIS1=2250 and SIZEAXIS2=590 are used to minimize data volume, while CENTERAXIS1 and CENTERAXIS2 are used to center the subarray readout on the zeroth order of G280 spectrum. These parameters are based upon similar observations obtained successfully in GOs 13574 & 15288 but have been adjusted to better center the zeroth order spectrum on the sub-array. We use FLASH=12 to meet the nominal count level. These parameters are based upon similar observations obtained successfully in GOs 13574 & 15288. With exposure time of 40 seconds, a few pixels will be slightly saturated in order to improve the duty cycle (since overhead > exposure time). The -1 order will contain complementary, non-saturated information for any region saturated. Additionally, for the few saturated pixels this spectra can be recovered in the +1 order by summation over pixels that have been bled into as a result of over-saturation (ISR WFC3 2010-10). We also add a FLASH of 9, which when combined with the natural background of about 4 e- per exposure will result in >12 e- and better CTE.