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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
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
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 …
A New Look At T Tauri Star Forbidden Lines: Mhd-Driven Winds From The Inner Disk, Min Fang, Ilaria Pascucci, Suzan Edwards, Uma Gorti, Andrea Banzatti, Mario Flock, Patrick Hartigan, Gregory J. Herczeg, Andrea K. Dupree
A New Look At T Tauri Star Forbidden Lines: Mhd-Driven Winds From The Inner Disk, Min Fang, Ilaria Pascucci, Suzan Edwards, Uma Gorti, Andrea Banzatti, Mario Flock, Patrick Hartigan, Gregory J. Herczeg, Andrea K. Dupree
Astronomy: Faculty Publications
Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. We report the first high-resolution (∆v ∼ 6 km s−1 ) analysis of [S II] λ4068, [O I] λ5577, and [O I] λ6300 lines from a sample of 48 T Tauri stars. Following Simon et al. (2016), we decompose them into three kinematic components: a high-velocity component (HVC) associated with jets, and a low-velocity narrow (LVC-NC) and broad (LVC-BC) components. We confirm previous findings that many LVCs are blueshifted by more than 1.5 km s−1 thus most likely trace a …
The Taurus Boundary Of Stellar/Substellar (Tboss) Survey. Ii. Disk Masses From Alma Continuum Observations, Kimberly Ward-Duong, J. Patience, J. Bulger, G. Van Der Plas, F. Ménard, C. Pinte, A. P. Jackson, G. Bryden, N. J. Turner, P. Harvey, A. Hales, R. J. De Rosa
The Taurus Boundary Of Stellar/Substellar (Tboss) Survey. Ii. Disk Masses From Alma Continuum Observations, Kimberly Ward-Duong, J. Patience, J. Bulger, G. Van Der Plas, F. Ménard, C. Pinte, A. P. Jackson, G. Bryden, N. J. Turner, P. Harvey, A. Hales, R. J. De Rosa
Astronomy: Faculty Publications
We report 885 μm ALMA continuum flux densities for 24 Taurus members spanning the stellar/substellar boundary with spectral types from M4 to M7.75. Of the 24 systems, 22 are detected at levels ranging from 1.0 to 55.7 mJy. The two nondetections are transition disks, though other transition disks in the sample are detected. Converting ALMA continuum measurements to masses using standard scaling laws and radiative transfer modeling yields dust mass estimates ranging from ∼0.3 to 20 M ⊕. The dust mass shows a declining trend with central object mass when combined with results from submillimeter surveys of more massive Taurus …
Tracing Slow Winds From T Tauri Stars Via Low-Velocity Forbidden Line Emission, M. N. Simon, I. Pascucci, Suzan Edwards, W. Feng, U. Gorti, D. Hollenbach, E. Rigliaco, J. T. Keane
Tracing Slow Winds From T Tauri Stars Via Low-Velocity Forbidden Line Emission, M. N. Simon, I. Pascucci, Suzan Edwards, W. Feng, U. Gorti, D. Hollenbach, E. Rigliaco, J. T. Keane
Astronomy: Faculty Publications
Using Keck/HIRES spectra (Δ v ∼ 7 km s−1) we analyze forbidden lines of [O I] 6300 Å, [O I] 5577 Å and [S II] 6731 Å from 33 T Tauri stars covering a range of disk evolutionary stages. After removing a high-velocity component (HVC) associated with microjets, we study the properties of the low-velocity component (LVC). The LVC can be attributed to slow disk winds that could be magnetically (magnetohydrodynamic) or thermally (photoevaporative) driven. Both of these winds play an important role in the evolution and dispersal of protoplanetary material. LVC emission is seen in all 30 stars with …
Interpreting Near Infrared Hydrogen Line Ratios In T Tauri Stars, Suzan Edwards
Interpreting Near Infrared Hydrogen Line Ratios In T Tauri Stars, Suzan Edwards
Astronomy: Faculty Publications
In accreting young stars, one of the prominent spectral features in the near-infrared is the Paschen and Brackett series in emission. We examine hydrogen line ratios for 16 classical T Tauri stars from SpeX spectra and assess the trends with veiling and accretion. The observed line ratios are compared with two theoretical models for line formation: (1) Baker & Menzel’s Case B for radiative ionization and recombination and (2) a set of local line excitation calculations designed to replicate the conditions in T Tauri winds and magnetic accretion columns (KF). While the comparison between Case B and observed line ratios …
Understanding The Origin Of The [Oi] Low-Velocity Component From T Tauri Stars, Elisabetta Rigliaco, Ilaria Pascucci, Uma Gorti, Suzan Edwards, D. Hollenbach
Understanding The Origin Of The [Oi] Low-Velocity Component From T Tauri Stars, Elisabetta Rigliaco, Ilaria Pascucci, Uma Gorti, Suzan Edwards, D. Hollenbach
Astronomy: Faculty Publications
The formation time, masses, and location of planets are strongly impacted by the physical mechanisms that disperse protoplanetary disks and the timescale over which protoplanetary material is cleared out. Accretion of matter onto the central star, protostellar winds/jets, magnetic disk winds, and photoevaporative winds operate concurrently. Hence, disentangling their relative contribution to disk dispersal requires identifying diagnostics that trace different star–disk environments. Here, we analyze the low-velocity component (LVC) of the oxygen optical forbidden lines, which is found to be blueshifted by a few km s−1 with respect to the stellar velocity. We find that the [O i] LVC …
Hot Gas Lines In T Tauri Stars, David R. Ardila, Gregory J. Herczeg, Scott G. Gregory, Laura Ingleby, Kevin France, Alexander Brown, Suzan Edwards, Christopher Johns-Krull, Jeffrey L. Linsky, Hao Yang, Jeff A. Valenti, Hervé Abgrall, Richard D. Alexander, Edwin Bergin, Thomas Bethell, Joanna M. Brown, Nuria Calvet, Catherine Espaillat, Lynne A. Hillenbrand, Gaitee Hussain, Evelyne Roueff, Eric R. Schindhelm, Frederick M. Walter
Hot Gas Lines In T Tauri Stars, David R. Ardila, Gregory J. Herczeg, Scott G. Gregory, Laura Ingleby, Kevin France, Alexander Brown, Suzan Edwards, Christopher Johns-Krull, Jeffrey L. Linsky, Hao Yang, Jeff A. Valenti, Hervé Abgrall, Richard D. Alexander, Edwin Bergin, Thomas Bethell, Joanna M. Brown, Nuria Calvet, Catherine Espaillat, Lynne A. Hillenbrand, Gaitee Hussain, Evelyne Roueff, Eric R. Schindhelm, Frederick M. Walter
Astronomy: Faculty Publications
For Classical T Tauri Stars (CTTSs), the resonance doublets of N v, Si iv, and Civ, as well as the He ii 1640 Å line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 stars: 1 Herbig Ae star, 28 CTTSs, and 6 WTTSs. We find that the Civ, Si iv, and N v lines in CTTSs all have similar shapes. We decompose the Civ and He ii lines into broad …
Characterizing The Iyj Excess Continuum Emission In T Tauri Stars, William J. Fischer, Suzan Edwards, Lynne A. Hillenbrand, John Kwan
Characterizing The Iyj Excess Continuum Emission In T Tauri Stars, William J. Fischer, Suzan Edwards, Lynne A. Hillenbrand, John Kwan
Astronomy: Faculty Publications
We present the first characterization of the excess continuum emission of accreting T Tauri stars between optical and near-infrared wavelengths. With nearly simultaneous spectra from 0.48 to 2.4μm acquired with HIRES and NIRSPEC on Keck and SpeX on the Infrared Telescope Facility, we find significant excess continuum emission throughout this region, including the I, Y, and J bands, which are usually thought to diagnose primarily photospheric emission. The IYJ excess correlates with the excess in the V band, attributed to accretion shocks in the photosphere, and the excess in the K band, attributed to dust in the inner …
Helium Emission From Classical T Tauri Stars: Dual Origin In Magnetospheric Infall And Hot Wind, Georgina Beristain, Suzan Edwards, John Kwan
Helium Emission From Classical T Tauri Stars: Dual Origin In Magnetospheric Infall And Hot Wind, Georgina Beristain, Suzan Edwards, John Kwan
Astronomy: Faculty Publications
High-resolution emission-line profiles of He I and He II in 31 classical T Tauri stars are analyzed with the aim of probing the environs of the star-disk interface in accreting low-mass young stars. The diagnostic power of the helium lines lies in their high-excitation potentials, which restrict their formation to a region either of high temperature or close proximity to a source of ionizing radiation. The He I profiles are decomposed into kinematic components that support the paradigm of magnetically controlled accretion from the disk onto the stellar surface but also require a significant contribution from a hot wind. A …