59 citations · 330 across the 19 of their papers we have counts for
20 papers
Stellar activity in a post-merger Giant star
Hans Moritz GGunther, Hans Moritz Günther, C. Melis +4
Binary stars are the progenitors of exotic objects, such as supernovae and gravitational wave sources. However, some systems merge earlier when the primary expands into a giant sta…
A superflare of BP Tau simultaneously caught by EP X-ray and TESS optical observations
Xingyu Zhou, Mingjun Liu, Gregory J. Herczeg +10
Multiwavelength observations of stellar flares trace the activity of different components of the stars' outer atmosphere, providing insight into their interactions. In the present…
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…
Stable Coronal X-Ray Emission Over Twenty Years of XZ Tau
Steven M. Silverberg, Hans Moritz Guenther, Pragati Pradhan +3
XZ Tau AB is a frequently observed binary YSO in the Taurus Molecular Cloud; XZ Tau B has been classified as an EXOr object. We present new Chandra/HETG-ACIS-S observations of XZ T…
PENELLOPE IV. A comparison between optical forbidden lines and UV lines in the Orion OB1b and -Ori associations
M. Gangi, B. Nisini, C. F. Manara +17
Observing the spatial distribution and excitation processes of atomic and molecular gas in the inner regions (< 20 au) of young (< 10 Myr) protoplanetary disks helps us to understa…
A spectacular jet from the bright 244-440 Orion proplyd: the MUSE NFM view
A. Kirwan, C. F. Manara, E. T. Whelan +8
In this work we present the highest spatial and spectral resolution integral field observations to date of the bipolar jet from the Orion proplyd 244-440 using MUSE NFM) observatio…
Coronal X-Ray Emission from Nearby, Low-Mass, Exoplanet Host Stars Observed by the MUSCLES and Mega-MUSCLES HST Treasury Survey Projects
Alexander Brown, P. Christian Schneider, Kevin France +8
The high energy X-ray and ultraviolet (UV) radiation fields of exoplanet host stars play a crucial role in controlling the atmospheric conditions and the potential habitability of…
A multi-wavelength view of the multiple activity cycles of ~Eridani
B. Fuhrmeister, M. Coffaro, B. Stelzer +3
Eridani is a highly active young K2 star with an activity cycle of about three years established using Ca II H & K line index measurements (S_MWO). This relatively short cycle…
Empirical Determination of the Lithium 6707.856 Å Wavelength in Young Stars
Justyn Campbell-White, Carlo F. Manara, Aurora Sicilia-Aguilar +20
Absorption features in stellar atmospheres are often used to calibrate photocentric velocities for kinematic analysis of further spectral lines. The Li feature at 6708 Å is…
Flares, Rotation, Activity Cycles and a Magnetic Star-Planet Interaction Hypothesis for the Far Ultraviolet Emission of GJ 436
R. O. Parke Loyd, P. C. Schneider, James A. G. Jackman +6
Variability in the far ultraviolet (FUV) emission produced by stellar activity affects photochemistry and heating in orbiting planetary atmospheres. We present a comprehensive anal…
Time-Variable Jet Ejections from RW Aur A, RY Tau and DG Tau
Michihiro Takami, Hans Moritz Guenther, P. Christian Schneider +17
We present Gemini-NIFS, VLT-SINFONI and Keck-OSIRIS observations of near-infrared [Fe II] emission associated with the well-studied jets from three active T Tauri stars; RW Aur A,…
The He I 10830 line as a probe of winds and accretion in young stars in Lupus and Upper Scorpius
J. Erkal, C. F. Manara, P. C. Schneider +6
The He I 1 micron line is a high excitation line which allows us to probe the innermost regions of protostellar disks, and to trace both accreting and outflowing material. We use X…
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-…
The stellar content of the ROSAT all-sky survey
S. Freund, S. Czesla, J. Robrade +2
We present and apply a method to identify the stellar content of the ROSAT all-sky survey (RASS). We performed a crossmatch between the RASS sources and stellar candidates selected…
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…
X-ray emission from candidate stellar merger remnant TYC 2597-735-1 and its Blue Ring Nebula
Hans Moritz Günther, Keri Hoadley, Maximilian N. Günther +3
Tight binary or multiple star systems can interact through mass transfer and follow vastly different evolutionary pathways than single stars. The star TYC 2597-735-1 is a candidate…
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…
H and He I absorption in HAT-P-32 b observed with CARMENES -- Detection of Roche lobe overflow and mass loss
S. Czesla, M. Lampón, J. Sanz-Forcada +22
We analyze two high-resolution spectral transit time series of the hot Jupiter HAT-P-32 b obtained with the CARMENES spectrograph. Our new XMM-Newton X-ray observations of the syst…
An X-ray activity cycle on the young solar-like star
M. Coffaro, B. Stelzer, S. Orlando +7
In 2015 we started the XMM-Newton monitoring of the young solar-like star Epsilon Eridani (440 Myr), one of the youngest solar-like stars with a known chromospheric CaII cycle. By…
High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood
M. Salz, P. C. Schneider, S. Czesla +1
Giant gas planets in close proximity to their host stars experience strong irradiation. In extreme cases photoevaporation causes a transonic, planetary wind and the persistent mass…