0 Assigned ID: 3750 ----- Attempting Submission 1 (Fri Mar 25 23:52:15 GMT 2022) ----- HST Phase I Proposal 3750 successfully submitted. Receipt: # 3750-1 ----- Attempting Submission 2 (Fri Mar 25 23:53:14 GMT 2022) ----- HST Phase I Proposal 3750 successfully submitted. Receipt: # 3750-2 ----- Attempting Submission 3 (Fri Mar 25 23:57:26 GMT 2022) ----- ----- Attempting Submission 4 (Mon Mar 28 12:32:32 GMT 2022) ----- UNSCHEDULABLE PHASE SPECIAL REQUIREMENTS ORBITAL VISIBILITY OVERRUN First submission of Phase II, July 12, 2022. There are no errors or warnings. Second submission of Phase II, Oct 16 2023. Shortened exposures to avoid occultation. Third submission of Phase II, Nov 22 2023. Adjusted phase constraints to make visit 01 possible. -966090246 ----- Attempting Submission 1 (Tue Jul 12 18:19:17 GMT 2022) ----- ----- Attempting Submission 2 (Mon Oct 16 21:44:01 GMT 2023) ----- ----- Attempting Submission 4 (Wed Nov 22 16:24:56 GMT 2023) ----- Visit 02 'at quadrature' has already been completed, so I believe the errors and warnings are irrelevant. Visit 01 'in eclipse' was updated to change phase constraints to accomidate the plan window. About 20% of the B-type stars are rotating very rapidly. Among these are the classical Be stars, which eject material and build up gaseous circumstellar 'decretion' disks. Rotation plays a significant role in the structure and evolution of massive stars, yet in many aspects is poorly understood. One viable evolutionary pathway to acquire near-critical rotation is through binary interaction - namely mass and angular momentum transfer. The remaining core of the mass donor is now a hot stripped star. Some models suggest the binary channel is dominant in creating rapid rotators. Yet, only about 15 rapidly rotating Be + stripped star binaries are known, virtually all of which were detected and characterized with UV spectroscopy. This proposal aims to characterize a new Be + stripped star binary, HD 92406, using HST UV spectroscopy. HD 92406 is exceptionally valuable as there are two stellar eclipses and two disk occulations per binary orbit - this is the only known eclipsing binary that hosts a Be star. HD 92406 is the first putative late-type Be + stripped star binary, occupying a unique niche in the rapidly rotating binary population. UV spectroscopy taken at two specific orbital phases (one when the sdO is hidden behind the Be star) offers the unique opportunity to measure directly the spectrum of an sdO star for the first time. With that, the parameters of the stripped star in HD 92406 can be determined with sufficient precision to reveal its evolutionary tracks via comparison with binary evolution models. A full analysis promises to make this a benchmark system, with properties determined with far higher precision than what is typically possible. This is an EB, with the primary (brighter in the UV) being a small stripped star (about B0), and a main-sequence late-B type star (about B9). We are planning two visits - one during the primary (total) eclipse (so the observed flux will be that from the MS B9 star), and one near quadrature. Besides the eclipses, there is low-amplitude pulsation (at about the <1% level) in optical photometry. For both visits (each 1 orbit) we intend to use the same instrument configuration: STIS/FUV-MAMA, E140M, 0.2x0.2, central wavelength = 1425. 1 exposure of 1100 s. STIS/NUV-MAMA, E230M, 0.2x0.2, central wavelength = 2124. 1 exposure of 424 s, to immediately follow the above FUV exposure. Based on our analysis of optical data for the system, we have a two-stellar-component model spectrum that we are using to estimate the expected UV flux. This model, with the extinction that we have calculated [E(B-V) = 0.065] matches very well with archival IUE data that cover the FUV + NUV. We have used this spectral model in the ETC, where for the in-eclipse visit the input model spectrum is only from the MS B9 star, and in the at-quadrature visit the model spectrum includes both stars (and so is brighter). REDUCED GYRO MODE: This should not have a significant impact on our proposal. As far as we can tell, our target is still in a good place on the sky even in reduced-gyro mode, and the additional two minutes of overhead is not significant. If, however, reduced-gyro mode limits our ability to schedule the single in-eclipse visit, we can modify the observing strategy to be less constrained. Dr. Labadie-Bartz specializes in time-series analysis of massive stars, especially the rapidly-rotating Be stars and binaries. He is leading an observing campaign to acquire time-series echelle spectscopy for Be stars that are being observed from space with TESS, of which our proposed target is a part of. He is additionally experienced in pulsational analysis and disk variability, and has been active in developing the science goals, as they relate to rapid rotation in massive stars, for a proposed UV spectropolarimetric space mission. Dr. Alex C. Carciofi is a leading expert in classical Be stars, having co-authored the currently most up to date review on these systems. He is the author of the radiative transfer code HDUST, which has been used in over 30 publications so far. Dr. Saul Rappaport has a decade of experience with analyzing photometric time series from Kepler, K2, and TESS. He has expertise with Be star binaries, in general, but especially with Be-star X-ray binaries. He wrote one of the early (1982) papers on how Be stars are spun up by accretion from a binary companion, and has continued to publish works on evolutionary paths modified by binary interaction. Tajan Henrique de Amorimis a first year PhD student working with Prof. Carciofi. He has developed the ray-tracing routines that have allowed us to model the disk and stellar eclipses as seen in TESS photometry. He is additionally improving radiative transfer codes to include the complexities that are inherent in our proposed target. Stellar Physics and Stellar Types 6 false false true false false false false 0 0 0 0 0 false SUPPORTED STAR B6-B9.5 V-IV BE EMISSION LINE STAR SDB NO Coordinates and PM from Gaia DR3. V658-CAR J2000 J2000 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No E230M 2124 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No E230M 2124 1700670046303 /tmp/OPVisit4292113566541769412.xml The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17182 :visit-id "01" :proposal-version -1 :trans-version "20230626" :date "22-Nov-2023 17:20:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 174416 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17182 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17182 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17182 :visit-id "01" :obset-id "B1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17182 :visit-id "01" :orbit-number 1 :pcs-time 443 :si-vis-utilization 2935 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3378 :pcs-gap 0 ) true 1 0 1700670256007 /tmp/OPVisit12021026791530312398.xml The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1679222209000 21.473678760823788 (Tic-Visit :proposal-id 17182 :visit-id "02" :proposal-version -1 :trans-version "20230626" :date "22-Nov-2023 17:24:15.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 174416 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17182 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17182 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 17182 :visit-id "02" :obset-id "B2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17182 :visit-id "02" :orbit-number 1 :pcs-time 443 :si-vis-utilization 2995 :al-overhead-at-end 0 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3378 :pcs-gap 0 ) true 1 1