0 Assigned ID: 5646 ----- Attempting Submission 1 (Tue Mar 26 20:59:23 GMT 2024) ----- FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser As mentioned in the email, we have added roll angles from our phase I submission. Update on Sep 18, 2024: Roll Angles updated update on Dec 18, 2024: timing constraint added -168826525 ----- Attempting Submission 1 (Fri Aug 16 17:48:00 GMT 2024) ----- HST Phase II Proposal 17768 successfully submitted. Receipt: # 17768-1 ----- Attempting Submission 2 (Wed Sep 18 15:39:04 GMT 2024) ----- ----- Attempting Submission 3 (Wed Dec 18 18:32:44 GMT 2024) ----- We chose to ignore this based on prior observations of the system. As described in GO-17427 (on the same target): Based on previous WFC3 data collected in GO-15830 observations, we estimate the background levels to be 300 to 400 electrons near planets b and c. Detecting the UV Accretion Signatures from PDS-70b Accretion is an essential step in gas giant planet-building and measuring the accretion rate illuminates the nature of planet-disk interactions as well as the timescale for and the process of planet formation. While there are numerous models for how planets may accrete material from the circumstellar disk in which they form, there is little consensus about the specifics given the lack of direct observational evidence. PDS-70b (a ~5 Myr-old giant planet) has had its accretion luminosity measured at H-alpha and in the continuum at 335 nm. However, the accretion rates derived from these measurements range over 2 orders of magnitude. For stars, the most accurate accretion indicators are shortward of 300 nm, as these more directly probe the accretion shock where infalling material impacts the surface. Similar observations of accreting planets are needed to better test whether an analogous process occurs in planet formation. We propose to observe PDS-70b between 120 nm and 300 nm at low resolution to search for accretion signatures in the UV to better constrain the accretion process on PDS 70b and measure a reliable accretion rate. We will observe PDS-70b at H-alpha both before and after each UV observation so we can calibrate the relationship between accretion signatures at H-alpha versus the UV, as is done for stars. We will also observe PDS-70b at medium resolution from 276 to 285 nm to measure the accretion line profile and constrain the planet's mass, a key quantity needed to reliably measure the accretion rate. These observations will provide some of the first UV observational data of planet accretion and will result in new and important insights into planet formation. This program aims to detect the UV flux from PDS 70b. The program is broken down into two visits. In one visit (5 orbits), we will acquire low-resolution spectra in order determine the flux from various UV lines and compare that to the planet's H-alpha flux, which we will also measure during that visit. In the other visit (3 orbits), we will acquire medium resolution spectra in order to resolve the line profile. We can capture both the star's and the planet's UV spectra by aligning the slit from STIS/MAMA at the planet's position angle using the 52 arcsec X0.2 arcsec slit. PDS-70b's apparent separation from its host star is large enough at the moment that the star's and the planet's signals will be spatially separated with STIS/MAMA spectroscopy, as shown in the original proposal. For the H-alpha observations, we will employ a four point dither pattern, as has been shown to work for previous observations of this system with WFC3/UVIS. We will use the same observation strategy as that of GO-17427, which observed this same system. The warning on FLASH level has been ignored based on prior observations of the system (GO-15830). For the low-resolution visit, after acquisition, we will start with the STIS/MAMA G2230L NUV observations for a partial orbit. We will then move to the STIS/MAMA G140L FUV observations for the remainder of the first orbit plus three full orbits. We finish with the WFC3 observations of H-alpha for an orbit. For the medium-resolution visit, after acquisition, we will spend the remainder of that orbit plus two full orbits observing the system with STIS/MAMA G230M (central wavelength 2800) NUV. PI Flagg has significant experience reducing, extracting, and analyzing UV spectral data (Flagg et al. 2021, ApJ, 921, 86; Flagg et al., 2022, ApJ, 934, 8). She has also analyzed line profiles from UV spectral data (Flagg et al., 2022, ApJ, 934, 8). CoI Johns-Krull has several decades of experience studying magnetospheric accretion signatures (e.g. Johns-Krull & Hatzes, 1997, ApJ, 487, 896; Johns-Krull et al. 2013, ApJ, 765, 11); he has also has created models to estimate the temperature of the accretion shocks (Ardila & Johns-Krull 2009, AIPC, 1094, 309). CoI Isella is an expert on circumplanetary disks and has been involved in detecting and characterizing the disks for PDS-70b and c (Isella et al. 2019, ApjL, 879, L25; Benisty et al. 2021, ApJL, 916, L2). CoI Weinberger is an expert on imaging both circumstellar disks and young, close companions (e.g. Weinberger et al. 1999, ApJL, 525, L53; Close et al. 2014, ApJL, 781, L30); she also has instituitonal access to MagAOX to acquire simultaneous H-alpha ground-based observations. CoI Jayawardhana is an expert on accretion signatures from young, planetary mass companions (e.g. Jayawardhana et al. 2006, ApJ, 642, 1206). CoIs Thanathibodee and Muzerolle have created and developed models that model shape of the accretion line profile from the magnetospheric flow, which depends on mass and radius (e.g. Muzerolle et al. 2001, ApJ, 550, 944; Muzerolle et al. 2005, ApJ, 625, 906; Thanathibodee et al. 2019, ApJ, 885, 94) CoI Zhou is an expert on direct imaging, particularly of young, substellar objects and has measured the H-alpha flux from PDS-70b previously (Zhou et al. 2021, AJ, 161, 244). CoI Turner is an expert on exoplanets and their magnetic fields (e.g. Turner et al. 2021, A&A, 645, A59). Exoplanets and Exoplanet Formation 6 false false true false false false false false SUPPORTED STAR EXTRA-SOLAR PLANETARY SYSTEM K V-IV T TAURI STAR NO RA, Dec are from Simbad (referenced to Gaia DR2). RA, Dec errors, Proper Motion, Radial Velocity are from Gaia DR2. V mag and uncertainty are from range given in Simbad. CD-408434 GSC07811-01917 J2000 J2000 B=13.42 (Simbad); Swift uvw2 (1599-2256 A.) = 1.5e-13 ergs/cm^2/s; uvwI (2253-2946 A.) = 2.7e-13 ergs/cm^2/s (ref. Joyce et al. 2020) STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/NUV-MAMA Spectroscopic No No G230M 2800 WFC3/UVIS Imaging No No F656N POS-TARG DITHER 0.02 LINE 0.02 false false 90 4 0 BOX 1 false The scheduling data was generated by CASM 32.1.3. CASM was run in Phase II mode. 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CASM was run in Phase II mode. (Tic-Visit :proposal-id 17768 :visit-id "02" :proposal-version -1 :trans-version "20240604" :date "18-Sep-2024 11:26:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 887552 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17768 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17768 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2668 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3049 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17768 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2669 :al-overhead-at-end 0 :internal-dur-at-end 315 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3049 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17768 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2669 :al-overhead-at-end 0 :internal-dur-at-end 577 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3049 :pcs-gap 0 ) true 3 0