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Full-Text Articles in Physical Sciences and Mathematics

Magnetospherically-Trapped Dust And A Possible Model For The Unusual Transits At Wd1145+017, J. Farihi, Ted Von Hippel, J. E. Pringle Aug 2019

Magnetospherically-Trapped Dust And A Possible Model For The Unusual Transits At Wd1145+017, J. Farihi, Ted Von Hippel, J. E. Pringle

Ted von Hippel

The rapidly evolving dust and gas extinction observed towardsWD1145+017 has opened a real-time window onto the mechanisms for destruction-accretion of planetary bodies onto white dwarf stars, and has served to underline the importance of considering the dynamics of dust particles around such objects. Here it is argued that the interaction between (charged) dust grains and the stellar magnetic field is an important ingredient in understanding the physical distribution of infrared emitting particles in the vicinity of such white dwarfs. These ideas are used to suggest a possible model for WD 1145+017 in which the unusual transit shapes are ...


Dust Production And Depletion In Evolved Planetary Systems, J. Farihi, Ted Von Hippel, Rik Van Lieshout, P.W. Cauley, Erik Dennihy, Et Al. Aug 2019

Dust Production And Depletion In Evolved Planetary Systems, J. Farihi, Ted Von Hippel, Rik Van Lieshout, P.W. Cauley, Erik Dennihy, Et Al.

Ted von Hippel

The infrared dust emission from the white dwarf GD 56 is found to rise and fall by 20 per cent peak-to-peak over 11.2 yr, and is consistent with ongoing dust production and depletion. It is hypothesized that the dust is produced via collisions associated with an evolving dust disc, temporarily increasing the emitting surface of warm debris, and is subsequently destroyed or assimilated within a few years. The variations are consistent with debris that does not change temperature, indicating that dust is produced and depleted within a fixed range of orbital radii. Gas produced in collisions may rapidly re-condense ...


A Tight Relation Between Spiral Arm Pitch Angle And Protplanetary Disk Mass, Si-Yue Yu, Luis C. Ho, Zhaohuan Zhu May 2019

A Tight Relation Between Spiral Arm Pitch Angle And Protplanetary Disk Mass, Si-Yue Yu, Luis C. Ho, Zhaohuan Zhu

Physics & Astronomy Faculty Publications

We use two-dimensional Fourier transformation to measure the pitch angle () of the dominant spiral Fourier mode of well-defined spiral arms in 13 protoplanetary disks, making use of near-infrared scattered-light images of AB Aur, SAO 206462, MWC 758, V1247 Ori, HD 142527, DZ Cha, LkHα 330, and HD 100453, and ALMA millimeter continuum images of Elias 2-27, IM Lup, AS 205, and HT Lup. We find that the measured pitch angle correlates strongly with disk mass (M D ), such that more massive protoplanetary disks have smaller pitch angles, following . Interestingly, four disks with a known companion (HD 142527, HD 100453, AS ...


Kinematic Links And The Coevolution Of Mhd Winds, Jets, And Inner Disks From A High-Resolution Optical [ [Oi] Survey, Andrea Banzatti, Ilaria Pascucci, Suzan Edwards, Min Fang, Uma Gorti, Mario Flock Jan 2019

Kinematic Links And The Coevolution Of Mhd Winds, Jets, And Inner Disks From A High-Resolution Optical [ [Oi] Survey, Andrea Banzatti, Ilaria Pascucci, Suzan Edwards, Min Fang, Uma Gorti, Mario Flock

Astronomy: Faculty Publications

We present a survey of optical [O I] emission at 6300 Å toward 65 T Tauri stars at the spectral resolution of ∼7 km s−1 . Past work identified a highly blueshifted velocity component (HVC) tracing microjets and a less blueshifted low-velocity component (LVC) attributed to winds. We focus here on the LVC kinematics to investigate links between winds, jets, accretion, and disk dispersal. We track the behavior of four types of LVC components: a broad and a narrow component (“BC” and “NC,” respectively) in LVCs that are decomposed into two Gaussians which typically have an HVC, and single-Gaussian LVC ...