411 citations · 1.3k across the 64 of their papers we have counts for
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V659 Cen: System Parameters Updated
Nancy Remage Evans, Charles Proffitt, Pierre Kervella +8
V659 Cen is a classical Cepheid which is part of a multiple system. Previous observations have shown that a hot companion dominates an ultraviolet spectrum and a cooler main sequen…
The Components of Cepheid Systems: The FN Vel System
Nancy Remage Evans, Pierre Kervella, Joanna Kuraszkiewicz +8
Cepheid masses continue to be important tests of evolutionary tracks for intermediate mass stars as well as important predictors of their future fate. For systems where the seconda…
The Orbit and Mass of the Cepheid AW Per
Nancy Remage Evans, Alexandre Gallenne, Pierre Kervella +17
The Cepheid AW Per is a component in a multiple system with a long period orbit. The radial velocities of Griffin (2016) cover the 38 year orbit well. An extensive program of inter…
A Multi-wavelength, Multi-epoch Monitoring Campaign of Accretion Variability in T Tauri Stars from the ODYSSEUS Survey. I. HST FUV and NUV Spectra
John Wendeborn, Catherine C. Espaillat, Sophia Lopez +17
The Classical T Tauri Star (CTTS) stage is a critical phase of the star and planet formation process. In an effort to better understand the mass accretion process, which can dictat…
Twenty-Five Years of Accretion onto the Classical T Tauri Star TW Hya
Gregory J. Herczeg, Yuguang Chen, Jean-Francois Donati +39
Accretion plays a central role in the physics that governs the evolution and dispersal of protoplanetary disks. The primary goal of this paper is to analyze the stability over time…
Chandra Observations of Six Peter Pan Disks: Diversity of X-ray-driven Internal Photoevaporation Rates Doesn't Explain Their Rare Longevity
E. Laos, J. P. Wisniewski, M. J. Kuchner +6
We present Chandra X-ray observations of 6 previously-identified Peter Pan objects, rare 40 Myr systems with evidence of primordial disk retention. We observe X-ray luminosities (0…
Pre main sequence: Accretion & Outflows
P. Christian Schneider, H. Moritz Günther, Sabina Ustamujic
Low-mass pre-main sequence (PMS) stars are strong X-ray sources, because they possess hot corona like their older main-sequence counterparts. Unique to young stars, however, are X-…
X-rays in Cepheids: Identifying Low-Mass Companions of Intermediate-Mass Stars
Nancy Remage Evans, Scott Engle, Ignazio Pillitteri +12
X-ray observations have been made of a sample of 20 classical Cepheids, including two new observations (Polaris and {\it l} Car) reported here. The occurrence of X-ray flux around…
Coronal and chromospheric emission in A-type stars
Hans Moritz Günther, Carl Melis, J. Robrade +3
Cool stars on the main sequence generate X-rays from coronal activity, powered by a convective dynamo. With increasing temperature, the convective envelope becomes smaller and X-ra…
Monitoring inner regions in the RY Tau jet
Taichi Uyama, Michihiro Takami, Gabriele Cugno +18
We present multi-epoch observations of the RY~Tau jet for H and [\ion{Fe}{2}] 1.644 \micron~emission lines obtained with Subaru/SCExAO+VAMPIRES, Gemini/NIFS, and Keck/OSIRIS in…
RW Aur A : SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration and Destruction in an 3 Myr Old Excited CTTS System
C. M. Lisse, M. L. Sitko, S. J. Wolk +9
We present 2007 - 2020 SpeX VISNIR spectral monitoring of the highly variable RW Aur A CTTS. We find direct evidence for a highly excited, IR bright, asymmetric, and time variable…
What's Behind the Elephant's Trunk? Identifying Young Stellar Objects on the Outskirts of IC1396
Steven M. Silverberg, Hans Moritz Guenther, Jinyoung Serena Kim +2
Empirically, the estimated lifetime of a typical protoplanetary disk is Myr. However, the disk lifetimes required to produce a variety of observed exoplanetary systems may…
PENELLOPE: the ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES) I. Survey presentation and accretion properties of Orion OB1 and -Orionis
C. F. Manara, A. Frasca, L. Venuti +69
The evolution of young stars and disks is driven by the interplay of several processes, notably accretion and ejection of material. Critical to correctly describe the conditions of…
Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids: Final Results
Nancy Remage Evans, H. Moritz Guenther, Howard E. Bond +13
Cepheids in multiple systems provide information on the outcome of the formation of massive stars. They can also lead to exotic end-stage objects. This study concludes our survey o…
Spatially resolved velocity structure in jets of DF Tau and UY Aur A
Anastasiia V Uvarova, Hans Moritz Günther, David A. Principe +1
Young stars accrete mass and angular momentum from their circumstellar disks. Some of them also drive outflows, which can be distinguished in optical forbidden emission lines (FELs…
The fastest components in stellar jets
Hans Moritz Günther, Catherine Espaillat, Kevin France +8
Young stars accrete mass from a circumstellar disk, but at the same time disk and star eject outflows and jets. These outflows have an onion-like structure where the innermost and…
White paper for Chandra cool attitude targets (CAT): Stellar activity with TESS and Chandra
Hans Moritz Günther, David A. Principe, Carl Melis +9
All cool stars show magnetic activity, and X-ray emission is the hallmark of this activity. Gaining an understanding of activity aids us in answering fundamental questions about st…
Optical dimming of RW Aur associated with an iron rich corona and exceptionally high absorbing column density
Hans Moritz Günther, T. Birnstiel, D. P. Huenemoerder +7
RW Aur is a binary system composed of two young, low-mass stars. The primary, RW Aur A, has undergone visual dimming events (~mag) in 2011, 2014-16, and 2017-2018. Visual…
TYC 8241 2652 1 and the case of the disappearing disk: no smoking gun yet
Hans Moritz Günther, Stefan Kraus, Carl Melis +12
TYC 8241 2652 1 is a young star that showed a strong mid-infrared (mid-IR, 8-25 mu) excess in all observations before 2008 consistent with a dusty disk. Between 2008 and 2010 the m…
Chandra Characterization of X-ray Emission in the Young F-Star Binary System HD 113766
C. M. Lisse, D. J. Christian, S. J. Wolk +3
Using Chandra we have obtained imaging X-ray spectroscopy of the 10 to 16 Myr old F-star binary HD 113766. We individually resolve the binary components for the first time in the X…
X-raying circumstellar material around young stars
P. C. Schneider, H. M. Günther
Young stars are surrounded by copious amounts of circumstellar material. Its composition, in particular its gas-to-dust ratio, is an important parameter. However, measuring this ra…
The nature of the 2014-2015 dim state of RW Aur revealed by X-ray, optical, and NIR observations
P. C. Schneider, H. M. Günther, J. Robrade +7
The binary system RW Aur consists of two classical T~Tauri stars (CTTSs). The primary recently underwent its second observed major dimming event (mag). We present new,…
X-ray to NIR emission from AA Tauri during the dim state - Occultation of the inner disk and gas-to-dust ratio of the absorber
P. C. Schneider, K. France, H. M. Günther +5
AA Tau is a well-studied, nearby classical T Tauri star, which is viewed almost edge-on. A warp in its inner disk periodically eclipses the central star, causing a clear modulation…
YSOVAR: Mid-Infrared Variability in NGC 1333
L. M. Rebull, J. R. Stauffer, A. M. Cody +17
As part of the Young Stellar Object VARiability (YSOVAR) program, we monitored NGC 1333 for ~35 days at 3.6 and 4.5 um using the Spitzer Space Telescope. We report here on the mid-…