0 Assigned ID: 4240 ----- Attempting Submission 1 (Wed May 24 03:30:21 GMT 2023) ----- HST Phase I Proposal 4240 successfully submitted. Receipt: # 4240-1 ----- Attempting Submission 2 (Wed May 24 19:10:59 GMT 2023) ----- 0 ----- Attempting Submission 1 (Mon Sep 25 12:26:16 GMT 2023) ----- Evidence is emerging from different observations that the clouds in the local interstellar medium, which surround the Sun and the nearest stars, are young, low-density, and colliding with each other. Indeed, the Sun may be currently moving through the collision zone of the Local Interstellar Cloud and the G Cloud. Archival observations support the high column density that would result from this interaction, but the densest region of the interaction remains unobserved. We propose to obtain high resolution spectra of four nearby stars in this region to measure the kinematic and physical properties of the interaction zone. Coupling E230H and E140M spectra will enable a direct test of the mixing by modeling the absorption features in narrow and strong LISM features (i.e., MgII) while also leveraging the numerous ions that are likely to show LISM absorption (e.g., HI, DI, CII, NI, OI, SiII) to obtain gas abundances, depletion patterns, temperatures, and turbulent velocities. The kinematics and the fundamental physical properties in the collision zone can be compared to the average cloud properties already derived in the literature. The collision and mixing of LISM clouds have important implications for our understanding of the timing and magnitude that the heliosphere expands and contracts. This, in turn, impacts the severity of the modulation of energetic cosmic rays into the solar system and on to the tops of planetary atmospheres. The proposed observations will test a new model of LISM cloud collisions that could significantly change the view we have of our immediate Galactic neighborhood. Target Selection and Availability: We plan to observe four nearby stars that lie along the collision zone of the nearest LISM clouds, the LIC and G clouds. The most important factors in target selection were location along this narrow strip that defines the longest path length through the mixed region and proximity. Three of our targets are <15 pc and the fourth is <20 pc away. Desired Spectral Coverage and Resolution: The high spectral resolution capabilities of STIS are necessary to model the ISM absorption line profiles. Only by resolving the velocity components of the mixed LIC and G clouds, can accurate physical measurements of gas abundances, dust depletion, temperature, and turbulent velocity be made. We will use the high resolution E230H grating to observe MgII and FeII. These heavy ions are not significantly broadened thermally, and provide sharp line profiles to resolve the velocity structure of the ISM along the line of sight. These transitions will be key to our kinematic analysis of the mixed absorption profiles. Hydrogen has a broad absorption profile, and does not necessarily require high spectral resolution, and therefore, to maximize S/N, we plan to use the E140M setting. Due to the wide spectral range of STIS, we would obtain practically the entire far-UV band from 1150-1700 A and several more ISM absorption lines (e.g., DI, CII, NI, OI, SiII, SiIII, AlII) in addition to Lyman-alpha. The velocity structure of the absorption can be derived by absorption of FeII and MgII at high spectral resolution and used for all transitions detected at medium resolution. Desired Aperture Size and Geocoronal Emission: The narrow aperture sizes of STIS are critical in order to minimize the contamination by the geocoronal Lyman-alpha emission. Depending on the time of year, the Earth's motion can Doppler shift the geocoronal line into the region of astrospheric absorption and contaminate our measurement. Our targets will require a minimal timing constraint to ensure that the geocoronal line is in the core of the ISM absorption (still allowing >7 months to perform observations). Desired Signal-to-Noise and Exposure Times: Because cool stars (even late-A and early-F stars) are emission line sources in the far-UV, estimating expected S/N for our planned spectra requires first estimating Lyman-alpha and MgII fluxes, which we can do by extrapolating from previously observed stars. Chromospheric line fluxes (such as MgII and Lyman-alpha) are related to X-ray fluxes. Wood et al. (2005) provide Lyman-alpha spectra for many stars, which serve as the comparison stars for our purposes here. All of our targets have X-ray observations and therefore have well determined X-ray luminosities (L_X). After acquisition, peakup, and observational overhead are considered, we expect at least 28 minutes to be available in the first orbit for the E230H exposure. This provides time to attain high S/N of >25 at the half-maximum (that is, one half FWHM from the line center, because it is unlikely that the ISM absorption will be centered at the same velocity as the star) of the strong MgII lines. After acquisition and overheads are considered, we expect at least 41 minutes of exposure time to be available in the second orbit for the E140M exposure, and 48 minutes in subsequent orbits. To obtain a S/N >15, which is required to model the Lyman-alpha profile, requires 2-4 orbits. Brightness Limits: The coolest stars in our sample have UV spectra characterized by minimal continua, but strong emission lines. For this reason, they all fall far short of the global brightness limit. For example, in the E230H setting, our earliest spectral type target (HD73752; G3V) only results in 23,700 counts s^-1, 12% of the MAMA bright limit. The emission lines for all targets also fall far short of the local brightness limit. The two emission lines of interest in this proposal (Lyman-alpha and MgII) are also the brightest, and therefore, the procedure given above for estimating the S/N near their peaks is also utilized to test for brightness limit violations. Again, HD73752 is the strongest MgII emission line sources in our sample, and in the brightest pixel, only generates 0.7 counts s^-1. PI Redfield and co-I Linsky are leading experts on the local interstellar medium (LISM). Both have extensive experience with the spectrographs on HST in observations of the interstellar medium, stellar atmospheres, circumstellar disks, and exoplanets. They have published a series of papers, based on high resolution HST spectra of nearby stars, detailing the physical and morphological structure of the gas and dust in the immediate vicinity of the Sun and the nearest stars. Co-I Swaczyna is an expert in the outer heliosphere and the local interstellar medium. Based on new measurements of inflowing interstellar particles from Ulysses, IBEX, and STEREO, he developed a model of the mixing of the LIC and G clouds. Co-I Wood has extensive experience in the analysis of stellar UV spectra taken by HST, including the study of the Lyman-alpha profile that contains ISM absorption in HI and DI, along with astrospheric and heliospheric absorption. Co-I Nisak is a postdoctoral researcher working with PI Redfield, his expertise is in high resolution spectroscopy of young, nearby stars. He is currently leading the analysis of archival LISM absorption toward nearby stars. Stellar Populations and the Interstellar Medium 6 false false true false false false false false SUPPORTED STAR G V-IV NO No target star was identified by the BOT in the observed field. DSS images clearly indicate a bright isolated target star (brightest within 100 arcsec). Clearly the target star is the dominant object in the field of view. HR3430 HIP42430 J2000 J2000 TYPE=G3V, B-V=0.83, E(B-V)=0, F-LINE(2796)=2.56e-12, W-LINE(2796)=0.6, F-LINE(1215)=0.65e-12, W-LINE(1215)=0.7 STAR K V-IV NO IUE SPECTRUM: LWP24840 Target star was identified by the BOT in the observed field. DSS images clearly indicate a bright isolated target star (brightest within 100 arcsec). Clearly the target star is the dominant object in the field of view. GJ259 HIP33817 J2000 J2000 TYPE=K1V, B-V=0.89, E(B-V)=0, F-LINE(2796)=3.59e-12, W-LINE(2796)=0.6, F-LINE(1215)=2.04e-12, W-LINE(1215)=0.7 STAR K V-IV NO No target star was identified by the BOT in the observed field. DSS images clearly indicate a bright isolated target star (brightest within 100 arcsec). Clearly the target star is the dominant object in the field of view. GJ269.0 HIP35296 J2000 J2000 TYPE=K1V, B-V=0.977, E(B-V)=0, F-LINE(2796)=3.94e-12, W-LINE(2796)=0.6, F-LINE(1215)=2.24e-12, W-LINE(1215)=0.7 STAR K V-IV NO No target star was identified by the BOT in the observed field. DSS images clearly indicate a bright isolated target star (brightest within 100 arcsec). Clearly the target star is the dominant object in the field of view. GJ167 HIP19884 J2000 J2000 TYPE=K5V, B-V=1.125, E(B-V)=0, F-LINE(2796)=1.22e-12, W-LINE(2796)=0.6, F-LINE(1215)=2.06e-12, W-LINE(1215)=0.7 STIS/NUV-MAMA Spectroscopic No No E230H 2713 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No E230H 2713 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No E230H 2713 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No E230H 2713 STIS/FUV-MAMA Spectroscopic No No E140M 1425 1718132520544 /private/var/folders/bl/s7q0tqnn5gbcbyvcfnrhj2rh0004nc/T/OPVisit13724095908214703524.xml The scheduling data was generated by CASM 32.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17425 :visit-id "01" :proposal-version -1 :trans-version "20240604" :date "11-Jun-2024 15:02:00.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 5 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 454000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17425 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17425 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2648 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3028 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2648 :al-overhead-at-end 194 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3028 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "01" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2648 :al-overhead-at-end 194 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3028 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "01" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2648 :al-overhead-at-end 194 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3028 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "01" :orbit-number 5 :pcs-time 380 :si-vis-utilization 2648 :al-overhead-at-end 194 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3028 :pcs-gap 0 ) true 5 0 SNR = 209.6709 Brightest Pixel = 18,286.41 e SNR = 137.5656 Brightest Pixel = 2,383.32 e Global Source Counts = 7,735,739.289 e SNR = 45.6222 Brightest Pixel = 1,152.72 e SNR = 9.9279 Brightest Pixel = 51.95 e SNR = 9.9279 Brightest Pixel = 51.95 e SNR = 9.9279 Brightest Pixel = 51.95 e SNR = 9.9279 Brightest Pixel = 51.95 e 1718132522597 /private/var/folders/bl/s7q0tqnn5gbcbyvcfnrhj2rh0004nc/T/OPVisit5711064565080232965.xml The scheduling data was generated by CASM 32.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17425 :visit-id "02" :proposal-version -1 :trans-version "20240604" :date "11-Jun-2024 15:02:02.0" :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 279984 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17425 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17425 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2652 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2652 :al-overhead-at-end 194 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2652 :al-overhead-at-end 194 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3032 :pcs-gap 0 ) true 3 0 SNR = 152.3254 Brightest Pixel = 9,499.47 e SNR = 58.8344 Brightest Pixel = 594.77 e Global Source Counts = 1,749,165.675 e SNR = 46.1826 Brightest Pixel = 805.47 e SNR = 17.6863 Brightest Pixel = 162.89 e SNR = 17.6863 Brightest Pixel = 162.89 e 1718132523966 /private/var/folders/bl/s7q0tqnn5gbcbyvcfnrhj2rh0004nc/T/OPVisit12526814472789127016.xml The scheduling data was generated by CASM 32.1. CASM was run in Phase II mode. 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CASM was run in Phase II mode. (Tic-Visit :proposal-id 17425 :visit-id "04" :proposal-version -1 :trans-version "20240604" :date "11-Jun-2024 15:02:05.0" :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 279984 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17425 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17425 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2698 :al-overhead-at-end 0 :internal-dur-at-end 113 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3078 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "04" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2698 :al-overhead-at-end 194 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3078 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17425 :visit-id "04" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2698 :al-overhead-at-end 194 :internal-dur-at-end 319 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3078 :pcs-gap 0 ) true 3 0 SNR = 154.2964 Brightest Pixel = 9,013.04 e SNR = 28.5556 Brightest Pixel = 276.62 e Global Source Counts = 615,814.596 e SNR = 27.3049 Brightest Pixel = 300.06 e SNR = 18.3482 Brightest Pixel = 175.31 e SNR = 18.3482 Brightest Pixel = 175.31 e