T. A. Carroll
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View article: Scene Co-pilot: Procedural Text to Video Generation with Human in the Loop
Scene Co-pilot: Procedural Text to Video Generation with Human in the Loop Open
Video generation has achieved impressive quality, but it still suffers from artifacts such as temporal inconsistency and violation of physical laws. Leveraging 3D scenes can fundamentally resolve these issues by providing precise control o…
View article: The PEPSI Exoplanet Transit Survey (PETS) – V. New Na <scp>d</scp> transmission spectra indicate a quieter atmosphere on HD 189733b
The PEPSI Exoplanet Transit Survey (PETS) – V. New Na <span>d</span> transmission spectra indicate a quieter atmosphere on HD 189733b Open
Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-series of HD 189733b, acquired with the PEPSI instrument at the…
View article: The PEPSI Exoplanet Transit Survey (PETS). V: New Na D transmission spectra indicate a quieter atmosphere on HD 189733b
The PEPSI Exoplanet Transit Survey (PETS). V: New Na D transmission spectra indicate a quieter atmosphere on HD 189733b Open
Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-series of HD 189733b, acquired with the PEPSI instrument at the…
View article: Electromechanical capacitor for energy transfer
Electromechanical capacitor for energy transfer Open
Inductive energy transfer between two magnets can be achieved with almost 100% efficiency with a transfer capacitor. However, the bulk and cost will be high, and reliability low if conventional capacitors are used. A homopolar machine, use…
View article: Zeeman Doppler imaging of<i>ξ</i>Boo A and B
Zeeman Doppler imaging of<i>ξ</i>Boo A and B Open
Aims. We present a magnetic-field surface map for both stellar components of the young visual binary ξ Boo AB (A: G8V, B: K5V). Methods. We employed high-resolution Stokes- V spectra obtained with the Potsdam Echelle Polarimetric and Spect…
View article: Zeeman Doppler Imaging of ksi Boo A and B
Zeeman Doppler Imaging of ksi Boo A and B Open
We present a magnetic-field surface map for both stellar components of the young visual binary ksi Boo AB (A: G8V, B: K5V). Employed are high resolution Stokes-V spectra obtained with the Potsdam Echelle Polarimetric and Spectroscopic Inst…
View article: VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole
VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole Open
We embarked on a high-resolution optical spectroscopic survey of bright Transiting Exoplanet Survey Satellite (TESS) stars around the Northern Ecliptic Pole (NEP), dubbed the Vatican-Potsdam-NEP (VPNEP) survey. Our NEP coverage comprises 1…
View article: VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole
VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole Open
Context. We embarked on a high-resolution optical spectroscopic survey of bright Transiting Exoplanet Survey Satellite (TESS) stars around the Northern Ecliptic Pole (NEP), dubbed the Vatican-Potsdam-NEP (VPNEP) survey. Aims. Our NEP cover…
View article: The PEPSI exoplanet transit survey (PETS) I: investigating the presence of a silicate atmosphere on the super-earth 55 Cnc e
The PEPSI exoplanet transit survey (PETS) I: investigating the presence of a silicate atmosphere on the super-earth 55 Cnc e Open
The study of exoplanets and especially their atmospheres can reveal key insights on their evolution by identifying specific atmospheric species. For such atmospheric investigations, high-resolution transmission spectroscopy has shown great…
View article: A confined dynamo: Magnetic activity of the K-dwarf component in the pre-cataclysmic binary system V471 Tauri
A confined dynamo: Magnetic activity of the K-dwarf component in the pre-cataclysmic binary system V471 Tauri Open
Context. Late-type stars in close binary systems can exhibit strong magnetic activity owing to rapid rotation supported by tidal locking. On the other hand, tidal coupling may suppress the differential rotation which is a key ingredient of…
View article: Probing the atmosphere of HD189733b with the Na i and K i lines
Probing the atmosphere of HD189733b with the Na i and K i lines Open
High spectral resolution transmission spectroscopy is a powerful tool to characterize exoplanet atmospheres. Especially for hot Jupiters, this technique is highly relevant, due to their high-altitude absorption, e.g. from resonant sodium (…
View article: The potassium absorption on HD189733b and HD209458b
The potassium absorption on HD189733b and HD209458b Open
In this work, we investigate the potassium excess absorption around 7699 Å of the exoplanets HD189733b and HD209458b. For this purpose, we used high-spectral resolution transit observations acquired with the 2 × 8.4 m Large Binocular Teles…
View article: New evidence for weak magnetic fields in Herbig Ae/Be stars
New evidence for weak magnetic fields in Herbig Ae/Be stars Open
In recent years Herbig Ae/Be stars receive considerable attention as their disks are believed to be the sites of on-going planet formation. Confirming the presence of magnetic fields in these stars is critical for understanding the transpo…
View article: The two magnetic components in the Herbig Ae SB2 system HD 104237
The two magnetic components in the Herbig Ae SB2 system HD 104237 Open
We present longitudinal magnetic field measurements $\\langle B_z \\rangle$ for\nthe Herbig Ae primary and the T Tauri secondary in the SB2 system HD 104237.\nThese measurements were carried out using high spectral resolution observations\…
View article: Surface magnetic activity of the fast-rotating G5 giant IN Comae, central star of the faint planetary nebula LoTr 5
Surface magnetic activity of the fast-rotating G5 giant IN Comae, central star of the faint planetary nebula LoTr 5 Open
Context. On the asymptotic giant branch, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Dynamic interaction between the planetary nebula and its central progenitor is poorly understood. The inter…
View article: Warm and cool starspots with opposite polarities. A high-resolution Zeeman-Doppler-Imaging study of II Pegasi with PEPSI
Warm and cool starspots with opposite polarities. A high-resolution Zeeman-Doppler-Imaging study of II Pegasi with PEPSI Open
We present a temperature and a magnetic-field surface map of the K2 subgiant of the active binary II Peg. Employed are high resolution Stokes IV spectra obtained with the new Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI…
View article: Warm and cool starspots with opposite polarities
Warm and cool starspots with opposite polarities Open
Aims. We present a temperature and a magnetic-field surface map of the K2 subgiant of the active binary II Peg. Employed are high resolution Stokes IV spectra obtained with the new Potsdam Echelle Polarimetric and Spectroscopic Instrument …
View article: Mapping EK Draconis with PEPSI
Mapping EK Draconis with PEPSI Open
Aims. We present the first temperature surface map of EK Dra from very-high-resolution spectra obtained with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope. Methods. Changes in spectr…
View article: Mapping EK Draconis with PEPSI - Possible evidence for starspot penumbrae
Mapping EK Draconis with PEPSI - Possible evidence for starspot penumbrae Open
We present the first temperature surface map of EK Dra from very-high-resolution spectra obtained with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope. Changes in spectral line profile…
View article: Observations of magnetic fields in Herbig Ae/Be stars
Observations of magnetic fields in Herbig Ae/Be stars Open
Models of magnetically driven accretion reproduce many observational properties of T Tauri stars. For the more massive Herbig Ae/Be stars, the corresponding picture has been questioned lately, in part driven by the fact that their magnetic…
View article: Mapping EK Draconis with PEPSI
Mapping EK Draconis with PEPSI Open
Aims. We present the first temperature surface map of EK Dra from very-high-resolution spectra obtained with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope. Methods. Changes in spectr…
View article: The B fields in OB stars (BOB) survey
The B fields in OB stars (BOB) survey Open
The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fie…
View article: Weak Magnetic Fields in Two Herbig Ae Systems: The SB2 AK Sco and the Presumed Binary HD 95881
Weak Magnetic Fields in Two Herbig Ae Systems: The SB2 AK Sco and the Presumed Binary HD 95881 Open
We report the detection of weak mean longitudinal magnetic fields in the Herbig Ae double-lined spectroscopic binary AK Sco and in the presumed spectroscopic Herbig Ae binary HD 95881 using observations with the High Accuracy Radial veloci…
View article: Antisolar differential rotation with surface lithium enrichment on the single K-giant V1192 Orionis
Antisolar differential rotation with surface lithium enrichment on the single K-giant V1192 Orionis Open
\n Context. Stars with about 1−2 solar masses at the red giant branch (RGB) represent an intriguing period of stellar evolution, i.e. when the convective envelope interacts with the fast-rotating core. During these mixing episodes freshly …
View article: Surface magnetism of cool stars
Surface magnetism of cool stars Open
Magnetic fields are essential ingredients of many physical processes in the interiors and envelopes of cool stars. Yet their direct detection and characterization is notoriously difficult, requiring high‐quality observations and advanced a…
View article: B fields in OB stars (BOB): The magnetic triple stellar system HD 164492C in the Trifid nebula.
B fields in OB stars (BOB): The magnetic triple stellar system HD 164492C in the Trifid nebula. Open
HD 164492C is a spectroscopic triple stellar system that has been recently detected to possess a strong magnetic field. We have obtained high-resolution spectroscopic and spectropolarimetric observations over a time span of two years and d…
View article: B field in OB stars (BOB): The outstandingly strong magnetic field in the evolved He-strong star CPD −62° 2124
B field in OB stars (BOB): The outstandingly strong magnetic field in the evolved He-strong star CPD −62° 2124 Open
The origin and evolution of magnetism in OB stars is far from being well\nunderstood. With approximately 70 magnetic OB stars known, any new object with\nunusual characteristics may turn out to be a key piece of the puzzle. We report\nthe …
View article: <i>B</i>fields in OB stars (BOB): Concluding the FORS 2 observing campaign
<i>B</i>fields in OB stars (BOB): Concluding the FORS 2 observing campaign Open
Aims. The B fields in OB stars (BOB) Collaboration is based on an ESO Large Programme to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. Methods. In the framework of this program, we ca…
View article: Time-series Doppler images and surface differential rotation of the effectively single, rapidly rotating K-giant KU Pegasi
Time-series Doppler images and surface differential rotation of the effectively single, rapidly rotating K-giant KU Pegasi Open
According to most stellar dynamo theories, differential rotation (DR) plays a\ncrucial role for the generation of toroidal magnetic fields. Numerical models\npredict surface differential rotation to be anti-solar for rapidly-rotating\ngian…
View article: Time-series Doppler imaging of the red giant HD 208472
Time-series Doppler imaging of the red giant HD 208472 Open
HD 208472 is among the most active RS~CVn binaries with cool starspots.\nDecade-long photometry has shown that the spots seem to change their\nlongitudinal appearance with a period of about six years, coherent with\nbrightness variations. …