0 Assigned ID: 7093 ----- Attempting Submission 1 (Tue Apr 14 21:32:29 GMT 2026) ----- For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS COS EXPOSURE TIME ROUNDED DOWN TO NEAREST 0.1 SECONDS We have already responded to the XMM team for the detailes of the simultaneous XMM observation. 860557617 ----- Attempting Submission 1 (Tue Aug 11 00:14:24 GMT 2026) ----- [exposure time warning] It looks all the exposures are set in increments of 0.1 seconds, but the error still appear. So I cannot find the reason. [Warning on the FP-POS position] FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. Stellar X-ray and extreme UV (XEUV) radiation from active M-dwarfs controls planetary atmospheric escape and photochemistry. The exoplanet community currently relies on archival flare templates like the 1985 Great Flare of AD Leo. However, these canonical datasets suffer from non-simultaneous coverage, NUV saturation, and lack of accompanying X-ray measurements. Because chromospheric and coronal energetics are tightly coupled, lacking simultaneous X-ray and UV data prevents self-consistent physical modeling, leaving the total XUV radiative output highly uncertain. We propose a strictly coordinated campaign targeting the highly active M-dwarf YZ CMi. While YZ CMi has a rich archival history with both observatories, our specific combination of HST/COS G130M/1222 and XMM-Newton X-ray+Optical Monitor modes has never been utilized simultaneously on this target. Capturing simultaneous, time-resolved X-ray, FUV, and NUV flare spectra will directly link impulsive chromospheric heating with gradual coronal evaporation. By combining these data with modern Radiative-Hydrodynamic (RHD) models, we will constrain the entire wavelength range between a few \AA~and 6000\AA. This is necessary for a comprehensive understanding of optically thin and thick flare-induced XEUV emissions, breaking theoretical degeneracies and accurately constraining the unobservable EUV flux. We will deliver these synchronized multi-wavelength templates as High-Level Science Products (HLSPs). This provides the highest-fidelity quantification of stellar flaring XUV radiation to date, establishing a crucial foundation for interpreting future exoplanet spectra in the Habitable Worlds Observatory (HWO) era. We request the corrdinated simultaneous HST - XMM observations of the highly active, nearby M4.5 dwarf YZ CMi (M4.5Ve, V=11.2, d = 5.99 pc). The high flare frequency of this star, which is well-quantified by previous optical (TESS), UV (Swift & HST), and X-ray (XMM) make it an ideal and highly reliable target for capturing a major stochastic flaring event within a limited coordinated observing window. We request 16 HST orbits (4 HST visits $\times$ 4 orbits to ease scheduling constraints), with which we can statistically expect to capture 5 flares. XMM time will be requested to simultaneously cover these HST orbits. With HST in a low-Earth orbit, 4 orbits (12 ks on target) corresponds to $\approx$20 ks of elapsed time of XMM (so 20ks x 4 visits = 80ks are approved for XMM). XMM's uninterrupted continuous viewing can help us to track the complete coronal evolution and bridge the unavoidable Earth-occultation gaps inherent to HST's orbit. (In stead of 4 orbits per each visit, having 3 orbits per each visit (but more visits so that the total orbits are still 16) would be an option if the scheduling is tough. But in that case, XMM scheduling needs to be splitted into also the same number of visits.) We require coordinated observations with XMM-Newton. On the basis of HST and XMM visibility information, there are periods of 5--6 weeks when simultaneous observations with XMM and HST are possible from early Oct. -- early Nov. 2026 and 2027. This is indicated using BETWEEN restrictions in the APT file to ensure proper scheduling. To maximize the scientific return, we request the XMM-Newton observations to be synchronized such that its continuous viewing begins prior to the first HST orbit's target acquisition, ensuring no flare onset or precursor emission is missed during the observatory setup. The HST FUV data analysis will proceed by making use of time-resolved spectral data of COS. So Time-Tag mode of COS is requested. We identify flaring times, and then separately analyze the time-evolution of the emission lines and continua, and compare them with model inputs. Our choice of the COS G130M/1222 configuratiom provides coverage from approximately 1060--1360 \AA with a detector gap from 1210--1225 \AA. Beyond avoiding the geocoronal Lyman-$\alpha$ emission to ensure detector safety during extreme flares, this setup provides access to crucial transition region and chromospheric diagnostics, including various N V, Si III, C II, C III lines. Furthermore, the TIME-TAG operating mode will allow us to extract spectra at custom temporal cadences retrospectively (e.g., 10s bins during the impulsive rise and 60s bins during the gradual decay), perfectly matching the dynamic timescales of the chromospheric heating. The proposed observations will not exceed the COS lifetime usage restrictions. We utilize data from PID 17428 which observed YZ CMi in the same COS/FUV G130M/1222 setting. The spectra with the highest (lf71z9hiq; COS.sp.2148236), which corresponds to the largest flare, and lowest (lf7109asq; COS.sp.2148308) fluxes bound the lifetime usage. COS ETC calculations give brightest pixel count rates of 0.014 (0.008 cps); multiplying by the total exposure time per visit ($\sim$12 ks) gives 168 (96) photons, which are well below the 2\% or 540 counts per visit limit. These previous data of YZ CMi with the same setup also ensure that the proposed program is free from Bright Object Protection (BOP) violation. The exposure setups described in this APT also basically follow the same observation from PID 17428. Dr. Yuta Notsu (PI) is a research scientist studying stellar flares, and have closely worked together with the Co-Is for many stellar flare papers. Since his PhD days, he has worked on coordinating stellar flare observations using Kepler, TESS, HST, XMM-Newton, NICER, Swift, and various ground-based facilities. Dr. Rachel Osten is an expert in multi-wavelength properties of stellar flares, from the X-ray to the radio, including spectral modeling, energy partitions, and properties of accelerated particles. Dr. Adam Kowalski is an associate professor, currently supervising Y. Notsu. A. Kowalski is an expert of radiative hydrodynamic modeling studies of solar and stellar flares, and he can lead modeling work of this project. A. Kowalski and R. Osten will help Y. Notsu to organize the team activities, on the basis of their long-term research experience on solar and stellar flare observational studies including various multi-wavelength observation campaigns. Dr. Isaiah Tristan is an expert in multi-wavelength M-dwarf flare phenomena, with expertise in both observation planning, data analysis (VLA, HST, TESS, etc.), and flare simulations (RADYN, RH/FP, GYRORT). He has experience in flare detection routines and will assist PI Notsu with analysis. Stellar Physics and Stellar Types Exoplanets and Exoplanet Formation 6 false false false false false false false true PRIMARY 80 true SUPPORTED STAR M V-IV NO We obtained J2000 ICRS coordinates from SIMBAD, which are corrected from the Gaia DR3 coordinates by accounting for proper motion (corrections automatically by Simbad). We take the uncertainty in RA and Dec (from Gaia) to be 1/2 of the annual parallax = 83.5 mas. This is to ensure that it is less than 0.4 arcsec required by our target acquisition algorithm. (the standard errors in RA and Dec, from Gaia DR3 are 0.0302 mas and 0.0233 mas, respectively). J2000 J2000 COS/FUV Spectroscopic No No G130M 1222 1786407086379 /Users/ynotsu/local_data/spectro/HST_2024Aug_Treasury/HST_cycle34_2026/PhaseII_HST_cycle34/OP-cache/18382_PhaseII-v01.xml The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18382 :visit-id "01" :proposal-version -1 :trans-version "20260618" :date "10-Aug-2026 18:11:25.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 6262000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18382 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18382 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "01" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "01" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 642 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 4 0 This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. 1785784617513 /Users/ynotsu/local_data/spectro/HST_2024Aug_Treasury/HST_cycle34_2026/PhaseII_HST_cycle34/OP-cache/18382_PhaseII-v02.xml The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18382 :visit-id "02" :proposal-version -1 :trans-version "20260618" :date "03-Aug-2026 13:16:56.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 6262000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18382 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18382 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "02" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 642 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 4 0 This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. 1785784620647 /Users/ynotsu/local_data/spectro/HST_2024Aug_Treasury/HST_cycle34_2026/PhaseII_HST_cycle34/OP-cache/18382_PhaseII-v03.xml The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18382 :visit-id "03" :proposal-version -1 :trans-version "20260618" :date "03-Aug-2026 13:16:59.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 6262000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18382 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18382 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "03" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "03" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "03" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 642 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 4 0 This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. 1785784624043 /Users/ynotsu/local_data/spectro/HST_2024Aug_Treasury/HST_cycle34_2026/PhaseII_HST_cycle34/OP-cache/18382_PhaseII-v04.xml The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18382 :visit-id "04" :proposal-version -1 :trans-version "20260618" :date "03-Aug-2026 13:17:03.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 6262000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18382 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18382 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "04" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "04" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 2402 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18382 :visit-id "04" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2487 :al-overhead-at-end 0 :internal-dur-at-end 642 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 4 0 This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is the same setup from PID#17428 (Visit Z9), which observed the same star. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464. This is bascially the same setup from PID#17428 (Visit Z9), which observed the same star. FP-POS=2 is selected to cover the Si III 120.65 nm but still avoid the Ly-alpha line center emission. We choose a conservative buffer-time of 120 sec, based on our previous observation PID#17464.