UV Exo-Aurorae: Multi-Wavelength Observations of a Radio Emitting T-dwarf to confirm Auroral Activity in the Ultraviolet.

0 Assigned ID: 6706 ----- Attempting Submission 1 (Thu Apr 10 21:09:20 GMT 2025) ----- HST Phase I Proposal 6706 successfully submitted. Receipt: # 6706-1 ----- Attempting Submission 2 (Thu Apr 10 21:21:19 GMT 2025) ----- HST Phase I Proposal 6706 successfully submitted. Receipt: # 6706-2 ----- Attempting Submission 3 (Thu Apr 10 21:34:18 GMT 2025) ----- Aug 8 2025 - Submission 1: Initial phase II submission. Submitting on behalf of PI due to APT connection issues. - PC Wilson Skipper. Feb 9th: Updated the proper motion of 2M1047+21 1581749572 ----- Attempting Submission 1 (Fri Aug 08 16:37:18 GMT 2025) ----- ----- Attempting Submission 2 (Mon Feb 09 13:06:30 GMT 2026) ----- Will discuss investigator mismatch with PI UV Exo-Aurorae: Multi-Wavelength Observations of a Radio Emitting T-dwarf to confirm Auroral Activity in the Ultraviolet. We propose simultaneous UV and radio observations with HST/STIS and the VLA of 2M1047+21, a cool, radio-emitting brown dwarf, to measure the first UV auroral emission from an extrasolar world. Over the last two decades, brown dwarfs have been discovered to emit powerful radio signatures indicative of aurorae. However, a conclusive detection of auroral UV emission on a brown dwarf has remained elusive. This program will constrain electron precipitation energies, resolve the magnetosphere structure and verify if auroral processes in brown dwarfs follow similar scaling relations to planetary aurorae. Detecting auroral emission in the UV would bridge the gap between the stellar and planetary regimes and complete picture of extrasolar auroral emission. We will observe the first ultraviolet aurora outside the solar system by stacking observations of 6 consecutive orbits with HST STIS G140L. Whiile previous attempts to observe UV exo-aurorae have been tentative o far, this will provide the longest observations yet of a brown dwarf in the UV. We aim to obtain a S/N >5 by stacking these observations over the 6 orbits between 1400-1600 Angstroms. This along with simultaneous VLA observations will allow us to confirm that the UV detection is auroral in nature. PI Cian O'Toole is a PhD student in Prof. Johanna Vos' group researching auroral varibility in brown dwarfs. Co-I Prof. Johanna Vos is an expert in brown dwarf variability and has substantial experience with HST, with two previous succesful programs, PIDs 16718 and 15924. Co-I Dr. Melodie Kao is a world expert in brown dwarf aurora studies and has prior experience with the VLA and radio aurora. Co-I Dr. Sebastian Pineda is a world expert in brown dwarf auroral studies and and is a leader in modelling auroral features. Co-I Dr. Yifan Zhou is an expert in variability monitoring of brown dwarfs with extensive experience in variability studies using the Hubble Space Telescope. Co-I Dr. Evert Nasedkin is an expert in modelling extra-solar atmospheres and using retrieval methods to model them. Co-I Dr. Allison McCarthy is an expert in variability monitoring and analysing auroral heating effects in the upper atmospheres of brown dwarfs. Co-I Anna Zuckerman is a PhD student in Dr. Sebastian Pineda's group, and her research is focused on determining the electron beam energy levels in auroral currents. Co-I Dr. Michael Fitzgerald is a world expert on brown dwarf aurora in the near infrared. Co-I Mr. Aidan Gibbs is a a PhD student in Dr. Michael Fitzgerald's group, and his research also focuses on brown dwarf aurorae. Co-I Dr. Robert Kavanagh is an expert on the magnetic fields of brown dwarfs and utilieses radio observations to observe brown dwarf aurora. Stellar Physics and Stellar Types 6 false true false false false false false true PRIMARY 4.3 true SUPPORTED STAR BROWN DWARF NO J2000 J2000 Spectral Type: T6.5; 2MASS J :15.819 [0.059], 2MASS H: 15.797 [0.120] , 2MASS K: 16.20 [0.03] (Flux values in order of: filter-name: flux-value [error]; reference: SIMBAD) STIS/FUV-MAMA Spectroscopic No No G140L 1425 1770642356589 Timing link suitability includes constraints ([02 After 01 by 1.1 to 1.2 days]) The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18113 :visit-id "01" :proposal-version -1 :trans-version "20250929" :date "09-Feb-2026 13:05:56.0" :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 609216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18113 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18113 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2599 :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 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18113 :visit-id "01" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2599 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18113 :visit-id "01" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2599 :al-overhead-at-end 0 :internal-dur-at-end 625 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 3 0 I used the T2 Phoenix 1200K model for the target acquisition. This is approx 300K hotter than this object, however, I normalised it to realistic T6.5 dwarf values. An exposiure time of 200 seconds should be ok, and is greater than the exposure time for the previous UV auroral observation of 2M1237 by HST PID 15870 (150 seconds). This should be ok. 1770642359882 Timing link suitability includes constraints ([02 After 01 by 1.1 to 1.2 days]) The scheduling data was generated by CASM 34.0. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18113 :visit-id "02" :proposal-version -1 :trans-version "20250929" :date "09-Feb-2026 13:05:59.0" :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 539632 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18113 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18113 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2599 :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 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18113 :visit-id "02" :orbit-number 2 :pcs-time 380 :si-vis-utilization 2599 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) (Tic-Orbit :proposal-id 18113 :visit-id "02" :orbit-number 3 :pcs-time 380 :si-vis-utilization 2599 :al-overhead-at-end 0 :internal-dur-at-end 625 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 3 0 I used the T2 Phoenix 1200K model for the target acquisition. This is approx 300K hotter than this object, however, I normalised it to realistic T6.5 dwarf values. An exposiure time of 200 seconds should be ok, and is greater than the exposure time for the previous UV auroral observation of 2M1237 by HST PID 15870 (150 seconds). This should be ok.