0 Assigned ID: 2757 ----- Attempting Submission 1 (Thu Mar 17 19:29:52 GMT 2022) ----- HST Phase I Proposal 2757 successfully submitted. Receipt: # 2757-1 ----- Attempting Submission 2 (Thu Mar 17 19:33:03 GMT 2022) ----- HST Phase I Proposal 2757 successfully submitted. Receipt: # 2757-2 ----- Attempting Submission 3 (Thu Mar 17 22:15:13 GMT 2022) ----- WFC3 EXPOSURE TIME ADJUSTED WFC3 EXPOSURE TIME ADJUSTED WFC3 EXPOSURE TIME ADJUSTED WFC3 EXPOSURE TIME ADJUSTED In order to eliminate overruns I've decreased the exposure times for exposures 4 (orbit 1) and 5 (orbit 2) and eliminated one of the filters in orbit 3. 438474105 ----- Attempting Submission 1 (Sun Jun 26 13:25:09 GMT 2022) ----- HST Phase II Proposal 17193 successfully submitted. Receipt: # 17193-1 ----- Attempting Submission 2 (Mon Jun 27 14:12:35 GMT 2022) ----- ----- Attempting Submission 3 (Fri Apr 07 19:57:17 GMT 2023) ----- ----- Attempting Submission 4 (Thu Jun 20 20:16:24 GMT 2024) ----- (1) I've had corresponded with Christian who said I should go ahead and submit anyway; apparently thre's an APT problem causing the visit planner and target confirmation tools not to run. (2) The errors are bizzare, and I have email into Karla about this. For instance: "Brief Description: Exposure duration 0.7 was not an integer multiple of .1 seconds. It has been adjusted to 0.7000000000000001" The WO class of Wolf-Rayet (WR) stars represent the most evolved type of massive star: their last hurrah before they undergo core-collapse. Abundance determinations of WOs thus give us a glimpe of the nucleosynthsis of massive stars at the very end of their lives, providing an unprecedented test of stellar evolutionary theory. We have recently finished an analysis of two WOs in the Large Magellanic Cloud (LMC) in order to determine their physical properties, including their abundances. Our results imply that the nuclear reaction rate for 12C+4He-->16O (long known to be uncertain) must be significantly lower than what is used in modern evolutionary models. This has enormous implications: among other things, it would eliminate the conflict between the theoretical black hole upper mass gap and the large black hole masses revealed by various gravitational wave events. Yet, our result hinges on the analysis of only two stars. WO-type WRs are rare: there are only three in the LMC, and the handful known in the Milky Way and in other galaxies are too reddened or distant to obtain the high-quality UV spectra necessary for their analysis. Unfortunately, the third LMC WO star, LH41-1042, has a companion only 0.1" away. However, by carefully aligning one of the narrow STIS slits, we can obtain a nearly uncontaminated spectrum of this third WO with just seven orbits. These data will provide an important test of our conclusion that the 12C+4He-->16O nuclear reaction rate is too high. LH41-1042 is the only remaining WO star that can be observed in both the UV and optical; obtaining these data can only be done with HST. The WO-type Wolf-Rayet star LH41-1042 has a companion star located located 0.122" at a position angle of -10 degrees. We have previous observations of the star in the UV with COS and in the optical with Magellan, but these spectra are all contaminated by the companion; these data however, provided the means to estimate the S/N and exposure times and alleviate any safety concerns. Our goal in this program is to obtain a relatively uncontaminated spectra. We have an F225W WFC3 imge which shows that the companio is about 1.8 mag fainter than the WR star in the UV; we also know that the companion is bound to be cooler than the WR and hence more of a problem as we go to longer wavelengths. We also know it doesn't dominate at optical wavelengths as there is no hint of absorption lines in our high S/N ground-based data. Exposure times and safety could be readily determined thanks to our combined COS and optical fluxed spectra. Our primarily goal, then, is to obtain good S/N UV spectra in the FUV and NUV using the G140L and G230L gratings using STIS/MAMA (Visit 1) and in the optical using the G430L and G750L gratings (Visit 2). The MAMA observations will be done with the 0.2x0.06" slit (available but unsupported with G140L), and the optical with the 52x0.05". (The use of the echelle slit for the UV observations removes safety concerns given other bright UV stars in the region.) In both cases we will require an orient angle (145+/- 20 or 325+/- 20) to place the companion star off to the side of the slit. [See below] (The alternative, of observing both stars on the slit and attempting to deblend them, was considered but rejected given the sampling.) Our acquisition will be done using a well-isolated O7V star located about 10" away; we will perform the ACQ/PEAK on this offset star as well. Coordinates have been carefully measured from the WFC3 image, and converted to ICRS by comparison with Gaia DR3 values. (The position for our science target required PSF fitting to remove the influence of the companion.) Our secondary goal is to obtain good fluxes for the WR component, and for this we will use a series of very short WFC3 exposures at the end of Visit 2. The FUV/NUV observations are straightforward and will require four orbits to obtain the required S/N; we will using time-tag and obtaining 2100 sec (orbit 1) + 3000 sec (orbit 2) + 500 sec (orbit 3) in FUV/G140L. During orbit 3 we switch to NUV/G230L and obtain 500 sec(remainer of orbit 3) and 3000 sec (orbit 4). In visit 2 we acquire and peakup on the offset star as before (exposures 1 and 2), and begin with observing with the G430L grating (exposue 3). There is essentially no background in our exposures, and so to alleviate CTE effects we will be using the E1 position. We will dither along the slit to 7 positions with the 52x0.05" slit. At each position we will do a CR=3 slit; thus the individual exposure times of these 2 1sub- exposures will be 33 seconds. Each of these will reach a continuum counts of about 2000 electrons/resolution element; i.e., these are low counts in the spectrum, only in the background. Using CR=3 not only helps eliminate CRs but also keeps the exposure times short enough to avoid saturation of the strong emission lines (the intensity of which are known from our ground-based data). This occupies most of orbit 1. Near the end of orbit 1 we switch to the G750L grating and begin a similar series of exposures (exposure 4). Again we will do a CR=3 and dither along the slit to 7 positions; each of the 21 exposure components will be 104 sec in length. Again, this will reach about 2000 e counts in the continuum per sub-exposure, and avoid saturating the strongest emission lines. At the end of the visibility period of orbit 2 we then take a fringe frame (exposure 5). We then switch to WFC3 and take 0.5 sec exposures in F275W, F336W, F438W, F555W, F625W, and F814W. We use a subarray to reduce CTE effects, and use the standard 4-point dither pattern for each exposure. Note about the orient angle. The companion is at a PA of -10 degrees relative to the WR companion. Thus to keep it off the slit, we want the slit to be at a PA of 80 degrees (-10+90). Our understanding from the documentation is thus that we want the orient angle to be PA + 45 or PA + 225. Thus we are requestion an orient angle near 125 or near 305. We allow +/- 20 deg slop around these optimal angles. Ms. Erin Aadland, Drs. Philip Massey, Kathryn Neugent, Nidia Morrell, John Hillier and Andreas Sander are all well-established researchers on Wolf-Rayet and other massive stars, and have studied them for most of their careers. Drs. Hiller and Sander are both experts on line-formation in WR atmospheres. Hillier wrote the CMFGEN code we have been using for modeling the stars described in this proposal, and Sander is a major contributer to PoWR, the Potsdam WR raditative transfer code. Ms. Erin Aadland is finishing her PhD thesis on the analysis of WC and WO stars, the basis for the present proposal. Drs. Massey, Neugent, and Morrell are primarily observers, and discovered the WO-type star described here. Recent relevant papers include: Aadland, Massey, Hillier, & Morrell (2022, ApJ, 924, 44) on the physical parameters of the WC stars used in this comparison with the WOs. Hillier, Aadland, Massey, & Morrell (2021, MNRAS, 503, 2726) on the discovery of nitrogen in an LMC WC-type WR. Sander, Hamann, Todt, et al. (2019, A&A, 621, 92) on the physical properties of Galactic WC and WO stars. Neugent, Massey, & Morrell (2018, ApJ, 863, 181) on the first complete census for WR stars in the LMC. Stellar Physics and Stellar Types 6 false false true false false false false false AVAILABLE EXT-STAR B0-B2 III-I NO J2000 J2000 B-V=-0.12, G=13.9 EXT-STAR WOLF RAYET - WC NO J2000 J2000 B-V=+0.07 STIS/CCD Imaging No No F28X50LP STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F438W WFC3/UVIS Imaging No No F555W WFC3/UVIS Imaging No No F625W WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.15 LINE false false 7 90.0 STIS-ALONG-SLIT 1 false POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false 1680890153480 The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. 1696114494000 286.97869402185347 (Tic-Visit :proposal-id 17193 :visit-id "01" :proposal-version -1 :trans-version "20220630" :date "07-Apr-2023 10:55:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1879152 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17193 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17193 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 3045 :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 3486 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17193 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 3028 :al-overhead-at-end 0 :internal-dur-at-end 334 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3486 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17193 :visit-id "01" :orbit-number 3 :pcs-time 392 :si-vis-utilization 3030 :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 3486 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17193 :visit-id "01" :orbit-number 4 :pcs-time 392 :si-vis-utilization 3028 :al-overhead-at-end 0 :internal-dur-at-end 630 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3486 :pcs-gap 0 ) true 4 0 1718820793265 /Users/massey/Dropbox/proposals/cycle30/LH411042/OP-cache/LH411042Rev-v02.xml The scheduling data was generated by CASM 31.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17193 :visit-id "02" :proposal-version -1 :trans-version "20240604" :date "19-Jun-2024 11:13:12.0" :trans-errors '(:WARNINGS 4 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1221920 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17193 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17193 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17193 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2753 :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 3151 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17193 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2754 :al-overhead-at-end 77 :internal-dur-at-end 720 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3151 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17193 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2385 :al-overhead-at-end 87 :internal-dur-at-end 426 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3151 :pcs-gap 0 ) true 3 0