0 Assigned ID: 5144 ----- Attempting Submission 1 (Mon Mar 25 02:28:48 GMT 2024) ----- HST Phase I Proposal 5144 successfully submitted. Receipt: # 5144-1 0 ----- Attempting Submission 1 (Mon Aug 12 12:16:41 GMT 2024) ----- Exploring the Origin of Gas in Debris Disks around A and B-type Stars Debris disks, which evolve from protoplanetary disks, were traditionally thought to be dust-poor and devoid of gas. However, recent ALMA surveys have revealed that at least 20 debris disks contain gas. Understanding the prevalence, origin, and evolution of this gas is crucial for studying the planetary systems' formation and evolution. The two leading origin theories propose that either the gas is primordial and therefore a remnant of the previous protoplanetary stage or second-generation and produced by the collisional cascade process. Thus far, the only detected molecule is CO, which quickly photodissociates if unshielded, producing neutral carbon (C I). In a primordial scenario, H2 shields CO against photodissociation, while in a secondary scenario, C I plays a pivotal role as a shielding agent. Our proposal aims to conduct a comprehensive survey of CO and C I gas in edge-on debris disks orbiting A and B-type stars, targeting seven disks not already observed by HST at sufficient sensitivity. Leveraging the sensitivity of HST/STIS far-UV absorption spectroscopy, we seek to detect cold gas co-located with dust disks at tens of AU. By detecting multiple transitions of CO and C I, we aim to accurately constrain their column densities and temperatures along the line of sight. We will then explore the systematic relationship between the C I/CO ratio and C I column density to determine whether C I is shielding CO in the high CO debris disk population, thereby confirming or refuting a secondary origin for the high CO mass disk population. Our goal is to carry out a UV spectroscopic line survey of the edge-on exocometary belts around bright (A and B-type), detecting several different transitions of C I and CO. We will target two sets of C I lines transitions at 1613 A and 1657 A with differing oscillator strengths, as well as a several CO bands containing tens of lines, including strong A-X bands and weaker intersystem bands. Covering these bands and lines with a variety of oscillator strengths at once will give us the best constraints on the C I and CO column density and temperature in these systems. We request the use of STIS due to its resolving power (R=114000). At the velocity resoutions of 2.6 km/s, we expect all transition lines to be unresolved unless heavily saturated, as the gas is expected to be cold ( tens of K). We request the use of STIS using the E140H grating (i 1562) with the narrow spectroscopic slit (0.2 x 0.09) recommended for the highest spectral resolution gratings and for minimizing airglow contamination. This will allow us to cover the main CO band A-X 0-0 (1544 A), 1-0 (1510 A) and 2-0 (1478 A) bands, as well as the weaker CO bands at (1464 A), (1470 A), (1480 A), (1486 A), (1493 A), (1503 A), (1517 A), (1526 A), (1535 A), (1551 A), (1526 A), (1535 A), (1551 A), (1577 A), (1588 A), (1605 A), and lines of C I (1613 A) and (1657 A). We note that the high resolution of STIS will also allow us to disentangle ISM lines if also present, although ISM components were not detected for CO and C I for the three systems already observed, so we don't anticipate this being an issu Aoife Brennan, Dr. Aki Roberge and Dr. Seth Redfield have extensive experience with HST UV spectroscopic observations. Together, they have led most past efforts to obtain gas abundances from UV spectroscopy of edge-on disks, as proposed for this project. Dr. Redfield is also an expert in the local interstellar medium, and his experience will be an asset for separating ISM absorption lines from circumstellar absorption lines in the spectra. Dr. Luca Matra, Dr. Sebastian Marino, Dr. Meredith Hughes, Dr. Quentin Kral and Dr. David Wilner are experts in debris disk observations and modelling, particularly at millimeter wavelengths. Dr. Matra and Dr. Hughes in particular are experts in observations of exocometary line emission and radiative transfer. Dr. Hales is an expert in observations of gas in disks (protoplanetary and debris) across the spectrum, but in particular optical spectroscopy where he led a major recent survey to look for atomic absorption in edge-on debris disks. Dr. Isabel Rebollido is an expert in detecting volatile gas around main-sequence stars and is PI for a JWST program which aims to observe NIR gas in debris disks. Dr. Karin Oberg and Dr. Wilner have extensive expertise related to gas in younger protoplanetary disks. Additionally, Dr. Oberg is also an expert in astrochemistry, which will aid us in interpreting the results from the perspective of the exocometary gas release. Both Dr. Daniela Iglesias and Dr. Julien Milli are experts in circumstellar disks and exoplanets. Kevin Smith is leading work observing H2 in edge-on disks in the near-infrared, which is crucial to investigating primordial gas. Exoplanets and Exoplanet Formation 6 false false false false false false SUPPORTED STAR A4-A9 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. Please see the proposal description for how stellar parameters were derived. For ETC calculations we used the predicted flux from the best fit model at 1562 A. HD14055 J2000 J2000 ohnson U=4.05+-0.01 mag. Model fits to Johnson U,B,V, Stromgren v,y, Tycho B, V, Gaia DR2, G, RP, 2MASS, J, H yields: Teff=9000(-800,+450) K, A_V=0.02(-0.02,+0.09), predicted flux at 1562 A = 7.79e-12 erg / s / cm^2 / A STAR A0-A3 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Model fits to Johnson B,V, Stromgren b,v, Tycho B, V, Gaia DR2 G, RP, BP, TESS, 2MASS, J, H, Ks, WISE W1, W2 yields: Teff = 9000(-300,+240)K, A_V = 0.01(-0.01,+0.1), predicted flux at 1562 A = 3.80e-12 erg / s / cm^2 / A STAR A0-A3 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Johnson U = 5.59+-0.01 mag. Model fits to Johnson B,U, V, Stromgren b,v,y, Tycho B, V, Gaia DR2 G, RP, BP, TESS, 2MASS, J, H, Ks, WISE W1, W2 yields: Teff= 9500 (-200, +20)K, A_V = 0.01(-0.01, +0.04), predicted flux at 1562 A = 2.64e-11 erg / s / cm^2 / A STAR A4-A9 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Johnson B = 8.07+-0.015 mag. Model fits to Johnson B, V, Tycho B, V, Gaia DR2 G, RP, BP, TESS, 2MASS, J, H, Ks, WISE W1, W2 yields: Teff = 8000(-100, +70)K, A_V = 0.007(-0.007,+0.05), predicted flux at 1562 A = 1.4e-13 erg / s / cm^2 / A STAR A4-A9 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Johnson U = 5.74+-0.08 mag. Model fits to Johnson U, B,V, Stromgren b,v,y, Tycho B, V, Gaia DR2 G, RP, TESS, 2MASS, H, Ks, WISE W1, W2 yields: Teff=7400K(-80, +150)K, A_V=0.01(-0.07,+0.01), predicted flux at 1562 A = 1.27e-13 erg / s / cm^2 / A STAR A4-A9 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Johnson B = 8.27+-0.01 mag. Model fits to Johnson B,V, Stromgren b,v,y, Tycho B, V, Gaia DR2 G, RP, BP, TESS, 2MASS, J, H, Ks, WISE W1, W2 yields: Teff=7850(-210,+140)K, A_V = 0.01 (+0.1,-0.01), predicted flux at 1562 A = 1.40e-13 erg / s / cm^2 / A STAR A4-A9 V-IV CIRCUMSTELLAR MATTER DISK NO This object was generated by the targetselector and retrieved from the SIMBAD database. For ETC calculations we used the predicted flux from the best fit model at 1562 A. J2000 J2000 Johnson B = 8.36+-0.02 mag. Model fits to Johnson B,V, Tycho B, V, Gaia DR2 G, RP, TESS, 2MASS, J, H, Ks, WISE W1, W2 yields: Teff=7700(-180,+270)K, A_V=0.014(0.014,+0.067), predicted flux at 1562 A = 2.74e-14 erg / s / cm^2 / A STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 STIS/FUV-MAMA Spectroscopic No No E140H 1562 The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. 1759829365000 219.90722980914506 (Tic-Visit :proposal-id 17752 :visit-id "01" :proposal-version -1 :trans-version "20240604" :date "12-Aug-2024 08:15:08.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 1914032 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17752 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17752 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2654 :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 3034 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2654 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3034 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 32.1.1. 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CASM was run in Phase II mode. 1745510238000 253.0790772630271 (Tic-Visit :proposal-id 17752 :visit-id "04" :proposal-version -1 :trans-version "20240604" :date "12-Aug-2024 08:14:41.0" :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 783232 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17752 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17752 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2625 :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 3005 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "04" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2625 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3005 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "04" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2625 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3005 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "04" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2625 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3005 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "04" :orbit-number 5 :pcs-time 380 :si-vis-utilization 2625 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3005 :pcs-gap 0 ) true 5 0 The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. 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CASM was run in Phase II mode. 1758291721000 267.150857881597 (Tic-Visit :proposal-id 17752 :visit-id "06" :proposal-version -1 :trans-version "20240604" :date "12-Aug-2024 08:13:35.0" :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 783232 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17752 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17752 :visit-id "06" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2630 :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 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "06" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "06" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "06" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "06" :orbit-number 5 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) true 5 0 The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. 1758625423000 268.1992432003263 (Tic-Visit :proposal-id 17752 :visit-id "07" :proposal-version -1 :trans-version "20240604" :date "12-Aug-2024 08:13:39.0" :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 783232 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17752 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17752 :visit-id "07" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2630 :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 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "07" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "07" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "07" :orbit-number 4 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "07" :orbit-number 5 :pcs-time 380 :si-vis-utilization 2630 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3010 :pcs-gap 0 ) true 5 0 The scheduling data was generated by CASM 32.1.1. CASM was run in Phase II mode. (Tic-Visit :proposal-id 17752 :visit-id "08" :proposal-version -1 :trans-version "20240604" :date "12-Aug-2024 08:13:43.0" :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 470144 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17752 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17752 :visit-id "08" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2739 :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 3119 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "08" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2739 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3119 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17752 :visit-id "08" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2739 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3119 :pcs-gap 0 ) true 3 0