0 Assigned ID: 3920 ----- Attempting Submission 1 (Thu May 11 20:38:34 GMT 2023) ----- FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser Resubmitting with the BEFORE date changed for Visit 1, due to the original date was missed because of HST safing. -1312479333 ----- Attempting Submission 1 (Fri Sep 08 20:39:57 GMT 2023) ----- HST Phase II Proposal 17531 successfully submitted. Receipt: # 17531-1 ----- Attempting Submission 2 (Mon Jan 29 15:58:46 GMT 2024) ----- We are FLASHing to about 45-50 e/pix, on advice of CoI Bellini, since the primary goal of the proposal is precise astrometry, for which we need to reduce CTE as much as possible. Planetary Nebulae in Star Clusters: Testing Membership with High-Precision Proper Motions Planetary nebulae (PNe) mark the rapid transition of low- to intermediate-mass stars from the AGB to the white-dwarf (WD) cooling sequence. PNe provide information on nucleosynthesis, mixing, mass loss, and the relation between a star's initial mass and that of its WD remnant. Even the very existence of a PN shows that its central star will not end life as a core-collapse supernova (CCSN). Unfortunately, for the vast majority of PNe, the masses and compositions of their progenitor stars are unknown. The only exception is in the case of a PN belonging to a star cluster. We propose to use precise astrometry, made possible by high-resolution HST imaging, to measure proper motions (PMs) of the central stars of three PNe that are candidate cluster members, and verify that the PMs agree with those of the clusters. Two of the PNe may belong to young open clusters, and one to an ancient globular cluster (GC). One of the open clusters, NGC 6067, is only 90 Myr old, implying an ususually high progenitor mass of 5.6 Msun (and a firm lower mass limit for CCSN progenitors). Another PN is a possible member of the GC Pal 6. Single-star evolution theory does not predict the existence of PNe in GCs, so that interacting-binary scenarios are needed--if the PN can be shown to be a cluster member. For two of our targets, there are archival first-epoch HST images available. In these cases, a one-orbit second-epoch observation will allow determinations of extremely precise PMs, and thus stringent tests of membership. For the PN candidate in NGC 6067, we propose first-epoch WFC3 images in Cycle 31, and a second epoch in Cycle 33, making it possible to confirm its unusually massive progenitor. We propose WFC3/UVIS imaging of the central stars of three PNe that are candidate members of three star clusters. Two of the clusters are open clusters, and one is a globular cluster. The aim is to measure precise proper motions (PMs) of the central stars, and of cluster members, in order to test whether the PNe are physical members of the clusters. 1. BMP J1613 in NGC 6067. There are no archival HST images of this target. We will obtain one orbit of imaging in Cycle 31, and a second one-orbit visit in Cycle 33. Bellini et al. (2014), Sahu et al. (2017, 2022), Libralato et al. (2019), and other authors, have demonstrated an astrometric precision of better than 0.02 pixel (+/-0.8 mas) per exposure can be achieved with WFC3/UVIS for well-exposed stellar images. WFC3 is increasingly affected by CTE. However, a correction algorithm, developed by Anderson (2021), can improve the precision to about 0.01 pixel if we place the target near the amplifier edge on the CCD. The uncertainty reduces to about +/-0.14 mas at a single epoch by combining 8 dithered exposures (possible during a one-orbit visit using subarrays). Thus the PM uncertainty over a 2-year interval would be +/-0.10 masyr . Hence it is readily possible with WFC3 astrometry to exceed the precision of the Gaia PM for this faint star by more than an order of magnitude (see the error bars in Fig. 2). This will provide an acid test of the PNN's cluster membership. We will use the F606W (wide V ) filter. This filter gives the best count rate for the central sta]. The F606W filter has an extremely well-characterised PSF for precision astrometry (e.g., Sahu et al. 2022 and references therein). (Note that our source is too faint, and the surrounding field too crowded, to use the technique of spatial-scanning astrometry developed by Riess et al. 2014.) For the central star of BMP J1613, the WFC3 Exposure Time Calculator indicates that a SNR=100 exposure takes 60 sec. We will use a dither-box pattern, and obtain 8 exposures of 60 sec each. The orbit will be filled out with a single 60-sec exposure in F814W, in order to measure the colour of the central star to help constrain its effective temperature and reddening (and increase the archival value of our data). All exposures will be pre-flashed, to further mitigate effects of CTE (e.g., Kuhn & Bajaj 2021). The surrounding field will provide the astrometric frame. Gaia DR3 indicates that, for example, there are about three dozen stars in a 81x81 arcsec field centred on the target, with magnitudes in the range 17 < G < 18. These bright stars will be well-exposed but not saturated in the WFC3 frames, providing a robust frame of stars with well-known PMs (including a handful of cluster members). This will allow us to determine the PM of the central star to high precision, and calibrated to the Gaia absolute frame. 2. PHR J1315 in AL 1 and JaFu 1 in Pal 3. For both of these targets, there are archival first-epoch HST frames. During Cycle 31, we will obtain the second-epoch frames for PM determination, one orbit each for the two targets. We will use WFC3/UVIS imaging essentially identical to that just described for BMPJ1613, but using the same filters as in the first-epoch frames. Total request: Three orbits in Cycle 31, one orbit in Cycle 33. PI HOWARD E. BOND (Adjunct Professor, Pennsylvania State University and Astronomer Emeritus, Space Telescope Science Institute) has extensive experience with HST observing. He specializes in stellar astronomy and has authored or coauthored over 250 refereed papers, with over 12,800 citations. CoI KAILASH SAHU (Astronomer, Space Telescope Science Institute) is an experienced user of HST and an authority on late stages of stellar evolution, astrophysical microlensing, and analysis of HST data. He has authored or coauthored over 160 refereed publications, with over 9,600 citations. CoI ANDREA BELLINI (Senior Staff Scientist, Space Telescope Science Institute) is an authority on astrometric and photometric analyses of HST images. He has authored or coauthored over 130 refereed publications, with over 6,000 citations. Stellar Physics and Stellar Types Stellar Populations and the Interstellar Medium 6 false false false false false false false false SUPPORTED STAR CIRCUMSTELLAR MATTER EJECTA PLANETARY NEBULA CENTRAL STAR This object was generated by the targetselector and retrieved from the SIMBAD database. Coords are from Gaia DR3. J2000 J2000 STAR CIRCUMSTELLAR MATTER EJECTA PLANETARY NEBULA CENTRAL STAR This object was generated by the targetselector and retrieved from the SIMBAD database. Coordinates updated from archival HST images. J2000 J2000 STAR CIRCUMSTELLAR MATTER EJECTA PLANETARY NEBULA CENTRAL STAR This object was generated by the targetselector and retrieved from the SIMBAD database. Coordinates updated from archival HST frames. J2000 J2000 WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F656N WFC3/UVIS Imaging No No F814W /Users/howardbond/data1/hstcycle31/PNe_in_clusters/OP-cache/17531-v01.xml The scheduling data was generated by CASM 32.0. CASM was run in Phase II mode. 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