0 Assigned ID: 702 ----- Attempting Submission 1 (Fri Apr 08 19:07:32 GMT 2016) ----- HST Phase I Proposal 702 (cycle24phase1-GO.pdf.apt) successfully submitted. Receipt: # 702-1 ----- Attempting Submission 2 (Fri Apr 08 19:49:17 GMT 2016) ----- STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL STIS SCIENCE TOO FAR FROM WAVECAL 0 ----- Attempting Submission 1 (Thu Jul 21 16:58:51 GMT 2016) ----- ----- Attempting Submission 2 (Fri Jun 09 16:52:54 GMT 2017) ----- ----- Attempting Submission 3 (Tue Oct 24 16:32:21 GMT 2017) ----- Availability=AVAILABLE mode was enabled to increase the duty cycle of the STIS observations and prevent auto-wave calibration from disrupting the transit time sequence in each STIS visit. An explicit wavecal has been added to the end of each observing sequence. We were given permission to use this mode in past HST programs (e.g. 12473 and 11572). We propose to use HST and Spitzer to measure the transmission spectrum of the recently discovered, hot sub-Saturn mass exoplanet WASP-127b. Its low mass (0.19 Mj) and large radius (1.39 Rj) give it the lowest density of any exoplanet with a radial velocity measured mass. It has the largest predicted atmospheric scale height of any planet, and orbits a bright (V~10.2) star, making it an exceptional target for atmospheric characterisation via transmission spectroscopy. With HST and Spitzer, we will measure the full transmission spectrum from 0.3 to 5 microns, covering water, sodium, and potassium absorption features, and scattering by molecular hydrogen or haze. The Spitzer transit photometry at 3.6 and 4.5 microns will be used alongside the HST spectrum to break the low abundance/cloud degeneracy which prevents constraints being made on atmospheric metallicity. With a low mass of 0.19 Mj, this planet sits in an unexplored mass range at the very low-end of gas giant planets, making WASP-127b strategecally important for constraining the planetary mass-metallicity relationship, which is important for understanding planet formation mechanisms. Our HST observations will proide a transmission spectrum for the transiting exoplanet WASP-127b across the 0.3-1.7 micron wavelength range. An additional two transits with the Spitzer Space Telescope will provide photometry at 3.6 and 4.5 microns. WASP-127b is a sub-Saturn mass, highly inflated exoplanet, and is extremely amenable to atmospheric studies. The broad wavelength coverage will probe water, sodium and potassium absoption features, Rayleigh scattering, and will allow us to break the degeneracies between clouds and low abundances. **Observing strategy: To construct the transmission spectrum, we require three separate transits of WASP-127b to be observed with HST: one with STIS+G430L, one with STIS+G750L, and one with WFC3+G141. All observations will be made in spectroscopic mode. The STIS observations will be made with the 52x2 arcsec slit to avoid slit losses. At the start of each visit, a standard phase-constrained acquisition image will be taken. The subsequent observing strategy consists of taking repeated exposures for the duration of the transit, plus time before and after the transit to establish the out-of-transit baseline flux. For the STIS observations, we will use stare mode with individual exposure times of 206 and 143 sec for G430L and G750L respectively. We will read out a subarray size of 128 pixels to reduce overheads (SIZEAXIS2=128). As in our previous Programs 14099, 12473 and 11740, we will override the default wavelength calibrations at the end of each exposure (WAVECAL=NO). This is done to improve the duty cycle and to allow the thermal breathing trends to be removed, which is only possible with an un-interrupted photometric time series. During Earth occultation in the last orbit, after the transit data has been taken, the wavelength calibration (and flat fielding for G750L) exposures are performed, a strategy successfully used in the past HST programs (14110, 12473, 11572, 11117, 13006, 11740). A single wavecal (using the 52"x0.2" slit) at the end of the sequence is sufficient for calibrating the spectra for the whole visit, as we find from cross-correlation (GO 12473) of the stellar spectra (taken using the 52"x2" slit) that the shifts are repeatably no more than 0.015 to 0.02 pixels on average during a 5 orbit visit. In addition, we keep an identical setup for the entire visit and do not switch between any settings to further minimize instrument-induced systematic errors in the photometric time series observations. For the WFC3 observations, we will use the forward spatial scanning mode with a scan rate of 0.17 arcsec/sec, using SPARS=10 and NSAMP=15, giving individual exposure times of 103 sec (i.e. resulting in a scan across 17.5 arcsec = 144 pixels per exposure). This will leave plenty of room on the detector to estimate the background flux. We will read out a subarray size of 256 pixels to reduce overheads. Each transit of WASP-127b lasts for 4 hours 20 minutes. We therefore require 5 consecutive HST orbits per visit. The first orbit serves to allow the telescope to thermally relax into its new pointing position, which is a standard procedure adopted by all HST exoplanet observations. The remaining 4 orbits will provide good phase coverage during transit, and allow for sufficient time to establish the baseline stellar flux necessary to accurately measure the transit depth. Strict phasing constraints will ensure at least 5 eposures will be taken either side of the transit. **Signal-to-noise estimates: WASP-127b is a bright target in the conventional sense (V=10.2mag, J=9.1mag). The challenge with exoplanet transmission spectroscopy is to measure subtle changes in the system brightness across different wavelength channels, via variations in the transit depth. We used the HST Exposure Time Calculator with the observational setup described above to calculate the following SNRs per resolution element per exposure: 530 for G430L, 579 for G750L, and 1901 for G141. Note that the G141 flux will be spread over ~73 pixel columns due to the spatial scan (see above), so there is no risk of saturation. --------- Additional Comments ---------- Availability=AVAILABLE mode was enabled to increase the duty cycle of the STIS observations and prevent auto-wave calibration from disrupting the transit time sequence in each STIS visit. An explicit wavecal has been added to the end of each observing sequence. We were given permission to use this mode in past HST programs (e.g. 12473 and 11572). Extrasolar Planets and Planet Formation 6 false false false false false true AVAILABLE STAR EXTRA-SOLAR PLANET G V-IV This object was generated by the targetselector and retrieved from the SIMBAD database. BD-03-2978 J2000 J2000 WFC3/IR Spectroscopic No No G141 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 1516636289377 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /private/var/folders/z3/xy_g1v_s5fz9yrhzb8thz4cr0001qc/T/OPVisit4623105400217761037.xml WASP-127. G430L. Each of the 5 HST orbits contain a non-interruptible sequence. It is essential that the 5 HST orbits be scheduled in a continuous block. (Tic-Visit :proposal-id 14619 :visit-id "01" :proposal-version -1 :trans-version "20171009" :date "22-Jan-2018 10:51:25.0" :trans-errors '(:WARNINGS 46 :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 152896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14619 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14619 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 1962 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2752 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2752 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2752 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "01" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2752 :al-overhead-at-end 123 :internal-dur-at-end 354 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2978 :pcs-gap 0 ) true 5 0 Short exposure to minimize instrument systematic of first exposure in each orbit. Short exposure to minimize instrument systematic of first exposure in each orbit. Short exposure to minimize instrument systematic of first exposure in each orbit. Short exposure to minimize instrument systematic of first exposure in each orbit. Explicit WAVECAL, auto-waves disabled 1516636303598 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /private/var/folders/z3/xy_g1v_s5fz9yrhzb8thz4cr0001qc/T/OPVisit2352539486835645221.xml WASP-127. G750L. Each of the 5 HST orbits contain a non-interruptible sequence. It is essential that the 5 HST orbits be scheduled in a continuous block. (Tic-Visit :proposal-id 14619 :visit-id "02" :proposal-version -1 :trans-version "20171009" :date "22-Jan-2018 10:51:38.0" :trans-errors '(:WARNINGS 64 :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 251056 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14619 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14619 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 1994 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2748 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2748 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "02" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2748 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "02" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2748 :al-overhead-at-end 120 :internal-dur-at-end 1806 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2978 :pcs-gap 0 ) true 5 0 Explicit WAVECAL, auto-waves disabled 1516636326167 The scheduling data was generated by CASM 25.2. CASM was run in Phase II mode. /private/var/folders/z3/xy_g1v_s5fz9yrhzb8thz4cr0001qc/T/OPVisit6816108440472836336.xml WFC3 IR transit of WASP-127. It is essential that the five orbits be scheduled in a coninuous block, free of the SAA. We will use the spatial scanning mode to lengthen the spectrum along the slit during the exposures, to avoid saturation on relatively long exposures. This mode greatly increases the efficiency. (Tic-Visit :proposal-id 14619 :visit-id "04" :proposal-version -1 :trans-version "20171009" :date "22-Jan-2018 10:52:03.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 1341920 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14619 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14619 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 1733 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2685 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "04" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2685 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "04" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2685 :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 2978 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14619 :visit-id "04" :orbit-number 5 :pcs-time 222 :si-vis-utilization 2685 :al-overhead-at-end 0 :internal-dur-at-end 434 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2978 :pcs-gap 0 ) true 5 0 Direct image for wavelegnth calibration. Phase constrained so transit occurs between 2nd and 3rd contact.