Polstar is a proposed NASA MIDEX mission that would feature a high resolution UV spectropolarimeter capable of measure all four Stokes parameters onboard a 60cm telescope. The mission would pioneer the field of time-domain UV spectropolarimetry. Time domain UV spectropolarimetry offers the best resource to determine the geometry and physical conditions of protoplanetary disks from the stellar surface to <5 AU. We detail two key objectives that a dedicated time domain UV spectropolarimetry survey, such as that enabled by Polstar, could achieve: 1) Test the hypothesis that magneto-accretion operating in young planet-forming disks around lower-mass stars transitions to boundary layer accretion in planet-forming disks around higher mass stars; and 2) Discriminate whether transient events in the innermost regions of planet-forming disks of intermediate mass stars are caused by inner disk mis-alignments or from stellar or disk emissions.
@article{arxiv.2111.06891,
title = {UV Spectropolarimetry with Polstar: Protoplanetary Disks},
author = {John P. Wisniewski and Andrei V. Berdyugin and Svetlana V. Berdyugina and William C. Danchi and Ruobing Dong and Rene D. Oudmaijer and Vladimir S. Airapetian and Sean D. Brittain and Ken Gayley and Richard Ignace and Maud Langlois and Kellen D. Lawson and Jamie R. Lomax and Motohide Tamura and Jorick S. Vink and Paul A. Scowen},
journal= {arXiv preprint arXiv:2111.06891},
year = {2022}
}