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JWST Proposal 1874 (Created: Wednesday, March 31, 2021 at 12:01:20 AM Eastern Standard Time) - Overview

1874 - JWST spectrophotometry of Cycle: 1, Proposal Category: GO

INVESTIGATORS Name Institution E-Mail Dr. Stuart Littlefair (PI) (ESA Member) University of Sheffield [email protected] Prof. Gregg Hallinan (CoI) (CoPI) (US Admin CoI California Institute of Technology [email protected] ) Dr. John Sebastian Pineda (CoI) (CoPI) University of Colorado at Boulder [email protected] Dr. Ben Burningham (CoI) (ESA Member) University of Hertfordshire [email protected] Dr. Jonathan David Nichols (CoI) (ESA Member) University of Leicester [email protected] Dr. Caroline Morley (CoI) University of Texas at Austin [email protected] Dr. Peter K. G. Williams (CoI) Harvard University [email protected] Dr. Paul Rimmer (CoI) (ESA Member) University of Cambridge [email protected] Dr. Melodie Kao (CoI) Arizona State University [email protected] Dr. Katelyn Allers (CoI) Bucknell University [email protected] Prof. John Evangelos Gizis (CoI) University of Delaware [email protected]

OBSERVATIONS Folder Observation Label Observing Template Science Target LSRJ1835+3259 NIRISS SOSS 1 NIRISS Full NIRISS Single-Object Slitless Spectroscopy (1) LSRJ1835+3259

ABSTRACT Our understanding of magnetic activity in low-mass and brown dwarfs was revolutionised by the discovery of brown dwarf "pulsars", with pulsed radio emission caused by massively scaled-up analogs of 's aurorae. These discoveries showed that the transition to -like occurs at the end of the stellar .

1 JWST Proposal 1874 (Created: Wednesday, March 31, 2021 at 12:01:20 AM Eastern Standard Time) - Overview The brown dwarf pulsars all show optical/NIR variability. It is claimed that this is causally linked to the radio emission and probably caused by the impact of auroral electrons on the brown dwarf . These auroral electrons may therefore have a profound impact on the atmosphere; altering the opacity, providing local heating, destroying dust clouds and triggering pre-biotic chemistry in the brown dwarfs. Since are expected on , similar effects may be in play.

The claim that the radio aurora cause the optical/NIR variability in brown dwarf pulsars is yet to be established. In particular, a model that claims elevayed H- opacity is the driver needs to be rigorously tested. Here we propose JWST spectrophotometry of a benchmark brown dwarf that we will use to understand the mechanism by which auroral electrons induce optical/NIR variability.

OBSERVING DESCRIPTION APT to obtain a time-series of spectra of LSR J1835+3259 with NIRISS/SOSS, with the aim of creating lightcurves for each spectral bin and measuring the of the surface feature causing the variabilty.

2 Proposal 1874-TargetsJWSTspectrophotometryofbrowndwarfpulsars Fixed Targets Extended=NO Description=[Brown dwarfs,Flarestars,Mdwarfs] Category= Comments: Highpropermotionsource.Position,andparallax fromGaiaDR2 (1) # LSRJ1835+3259 Name Equinox: J2000 Dec: +325953.31(32.99814d) RA: 183537.8804(278.9078350d) Target Coordinates 3 Epoch ofPosition:2000.0 : 0.1758244" Proper MotionDec:-754.841mas/yr Proper MotionRA:-72.840mas/yr Targ. Coord.Corrections Miscellaneous Proposal 1874-Observation1JWSTspectrophotometryofbrowndwarfpulsars Special Requirements Spectral Elements Template Acquisition Fixed Targets Diagnostics Observation No Parallel Time SeriesObservation Aperture PARange95to270Degrees (V394.43012982to269.43012982) 2 1 # SUBSTRIP256 Subarray 1 # Extended=NO Description=[Brown dwarfs,Flarestars,Mdwarfs] Category=Star Comments: Highpropermotionsource.Position,andparallax fromGaiaDR2 (1) # (Visit 1:1)Warning(Form):OverheadsareprovisionaluntiltheVisitPlanner hasbeenrun. (Exposure) Warning(Form):ExposureDurationexceedsthelimitof10000.0 seconds.AbovethislimititispossiblethataHighGainAntennamovemayoccurduringtheexposure. (NIRISS FullOrbit(Obs1))Warning(Form):ExposureDurationexceeds thelimitof10000.0seconds.AbovethisitispossiblethataHighGainAntennamovemayoccurduringexposure. Observing Template:NIRISSSingle-ObjectSlitlessSpectroscopy Diagnostic Status:Warning Proposal 1874,Observation1:NIRISSFullOrbit LSRJ1835+3259 Name SAME Target NISRAPID NISRAPID Readout Pattern SOSSFAINT Acquisition Mode Equinox: J2000 Dec: +325953.31(32.99814d) RA: 183537.8804(278.9078350d) Target Coordinates 4 4 Groups/Int F480M Filter Integrations/Exp 30 475 NISRAPID Readout Pattern 4 Epoch ofPosition:2000.0 Parallax: 0.1758244" Proper MotionDec:-754.841mas/yr Proper MotionRA:-72.840mas/yr Targ. Coord.Corrections Total Dithers true Include F277WExposure? 19 Groups/Int 1 1 1 Integrations/Exp Total Integrations 30 475 1 Total Integrations 824.714 13057.978 Total ExposureTime Miscellaneous 1.024 Time Total Exposure Wed Mar3105:01:20GMT2021 31944 31944 ETC Wkbk.CalcID 31944 ID ETC Wkbk.Calc