A5060979586- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Spectroscopy and Laser Applications
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- Spacecraft Design and Technology
- Advanced materials and composites
- Spectroscopy Techniques in Biomedical and Chemical Research
- Planetary Science and Exploration
- Scientific Measurement and Uncertainty Evaluation
- CCD and CMOS Imaging Sensors
- Cloud Computing and Resource Management
- Atomic and Molecular Physics
- Metal and Thin Film Mechanics
- Space Exploration and Technology
- Cold Atom Physics and Bose-Einstein Condensates
- Distributed and Parallel Computing Systems
Leibniz Institute for Astrophysics Potsdam
2015-2024
American Industrial Partners (United States)
2023
Plansee (Germany)
2013-2018
Institut für Sonnenphysik
2012
Zuse Institute Berlin
2007
University of Potsdam
2004
University of Vienna
2000-2002
PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric Spectroscopic Instrument for 2x8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 can cover entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3kx10.3k CCDs with 9-{\mu}m pixels peak quantum efficiencies 96 % record a total 92 echelle orders. We introduce new variant wave-guide image slicer 3, 5, 7 slices between %. A six...
Aims. We determine period-luminosity relations for Milky Way Cepheids in the optical and near-IR bands. These can be used directly as reference extra-galactic distance determination to Cepheid populations with solar metallicity, they form basis a direct comparison obtained exactly same manner stars Magellanic Clouds, presented an accompanying paper. In that paper we show metallicity effect is very small consistent null effect, particularly bands, combine here all 111 from Way, LMC SMC best relation.
We study the time variations of cycles 20 active stars based on decades-long photometric or spectroscopic observations. A method time-frequency analysis, as discussed in a companion paper, is applied to data. Fifteen definitely show multiple cycles; records rest are too short verify timescale for second cycle. The typically systematic changes. For three stars, we found two each them that not harmonics, and which vary parallel, indicating common physical mechanism arising from dynamo...
Abstract STELLA is a robotic observatory with two fully automatic telescopes (STELLA‐I and STELLA‐II) located at the Teide Observatory in Tenerife, Spain. Not only are but also entire observatory, no human presence needed for observing ‐ not even remote control. STELLA‐I supports high‐resolution, fiber‐fed benchmounted echelle spectrograph wide‐field CCD imaging photometer while STELLA‐II feeds similar wide‐band testbed prototype adaptive optics telescopes. The first telescope scheduled...
Abstract The bright supergiant, Betelgeuse (Alpha Orionis, HD 39801), underwent a historic optical dimming during 2020 January 27–February 13. Many imaging and spectroscopic observations across the electromagnetic spectrum were obtained prior to, during, subsequent to this event. These of reveal that substantial surface mass ejection (SME) occurred moved out through extended atmosphere supergiant. A photospheric shock in 2019 January–March, progressed star following 11 months led dust...
We have used two robotic telescopes to obtain time-series high-resolution spectroscopy and V I and/or by photometry for a sample of 60 active stars. Orbital solutions are presented 26 SB2 19 SB1 systems with unprecedented phase coverage accuracy. The total 6,609 R=55,000 echelle spectra also systematically determine effective temperatures, gravities, metallicities, rotational velocities, lithium abundances absolute H{\alpha}-core fluxes as function time. is infer unspotted brightness, - b y...
We observed the Saturn-mass and Jupiter-sized exoplanet HAT-P-19b to refine its transit parameters ephemeris as well shed first light on transmission spectrum. monitored host star over one year quantify flux variability correct spectrum for a slope caused by starspots. A of was spectroscopically with OSIRIS at Gran Telescopio Canarias in January 2012. The spectra target comparison covered wavelength range from 5600 7600 AA. One high-precision differential curve created integrating entire...
Multi-colour broad-band transit observations offer the opportunity to characterise atmosphere of an extrasolar planet with small- medium-sized telescopes. One most favourable targets is hot Jupiter HAT-P-32 b. We combined 21 new this 36 previously published light curves for a homogeneous analysis transmission spectrum from Sloan u' band z' band. Our results rule out cloud-free planetary models solar metallicity. Furthermore, discrepancy at reddest wavelengths makes recent tentative detection...
FK Comae is a rapidly rotating magnetically active star, the light curve of which modulated by cool spots on its surface. It was first star where "flip-flop" phenomenon discovered. Since then, flip-flops in spot activity have been reported many other stars. Therefore, it interest to perform more thorough study evolution Com. In this study, we analyse 15 years photometric observations with two different time series analysis methods, special emphasis detecting flip-flop type events from data....
The depth of a secondary eclipse contains information both the thermally emitted light component hot Jupiter and reflected component. If dayside atmosphere planet is assumed to be isothermal, it possible disentangle both. In this work, we analyze 11 curves HAT-P-32b obtained at 0.89 $\mu$m in z' band. We obtain null detection for with state-of-the-art precision, -0.01 +- 0.10 ppt. confirm previous studies showing that non-inverted model disagreement measured emission spectrum HAT-P-32b....
Context . Betelgeuse, a red supergiant star of semi-regular variability, reached historical minimum brightness in February 2020, known as the Great Dimming. Even though has returned to values prior Dimming now, it continues exhibit highly unusual behavior. Aims Understanding long-term atmospheric motions Betelgeuse and its variability could be clue nature mass-loss process supergiants. Our goal is study dynamics photosphere, including during Methods We applied tomographic method, which...
We reconstruct a time series of 28 surface temperature maps (Doppler-images) the spotted single K2-dwarf LQ Hya from 35 consecutive stellar rotations in Nov.–Dec. 1996. Two more are obtained data late April and early May 2000. All show spot activity preferably at low latitudes between -20° +50°, with concentration band centered around +30°, only occasional evidence for higher-latitude extension. No trace polar is found any above epochs. Most this morphology can be reproduced by our flux-tube...
The Astrophysical Institute Potsdam (AIP) and the Instituto de Astrofísica Canarias (IAC) inaugurated robotic telescopes STELLA‐I STELLA‐II (STELLar Activity) on Tenerife May 18, 2006. observatory is located Izaña ridge at an elevation of 2400 m near German Vacuum Tower Telescope. STELLA consists two 1.2 alt‐az telescopes. One telescope fiber feeds a bench‐mounted high‐resolution echelle spectrograph while other wide‐field imaging photometer. Both scopes work autonomously by means artificial...
Context. The detection of trends or gradients in the transmission spectrum extrasolar planets is possible with observations at very low spectral resolution. Transit measurements sufficient accuracy using selected broad-band filters allow for an initial characterization atmosphere planet.
Context. Transit events of extrasolar planets offer the opportunity to study composition their atmospheres. Previous work on transmission spectroscopy close-in gas giant (TrES)-3 b revealed an increase in absorption towards blue wavelengths very large amplitude terms atmospheric pressure scale heights, too be explained by Rayleigh-scattering planetary atmosphere.
Brightness inhomogeneities in the stellar photosphere (dark spots or bright regions) affect measurements of planetary transmission spectrum. To investigate star M dwarf GJ 1214, we conducted a multicolor photometric monitoring from 2012 to 2016. The measured variability shows periodicity 125 +- 5 days, which interpret as signature rotation period. This value overrules previous suggestions significantly shorter A light curve inversion data yields an estimation flux dimming permanent spot...
Context. The properties, distribution, and evolution of inhomogeneities on the surface active stars, such as dark spots bright faculae, significantly influence determination parameters an orbiting exoplanet. chromatic effect they have transmission spectroscopy, for example, could affect analysis data from future space missions James Webb Space Telescope Ariel. Aims. To quantify mitigate effects those phenomena, we developed a modelling approach to derive distribution properties regions by...
Abstract We examine a century of radial velocity, visual magnitude, and astrometric observations the nearest red supergiant, Betelgeuse, in order to reexamine century-old assertion that Betelgeuse might be spectroscopic binary. These data reveal varying stochastically over years decades due its boiling, convective envelope, periodically with 5.78 yr long secondary period (LSP), quasiperiodically from pulsations periods several hundred days. show LSP is consistent between velocity sets, argue...
The STELLA project consists of two robotic 1.2m telescopes to simultaneously monitor stellar activity with a high resolution echelle spectrograph on one telescope, and photometric imaging instrument the other telescope. observatory is located at Observatorio del Teide Canary island Tenerife. Echelle (SES) has been operated in mode for years now, produced approximately 10,000 spectra entire optical range between 390 900 nm spectral 55,000 peak shutter-open time 93%. Although we do not use an...
Abstract The system AR Aur is a young late B-type double-lined eclipsing binary with primary star of HgMn peculiarity. We applied the Doppler imaging method to reconstruct distribution Fe and Y over surface using spectroscopic time series obtained in 2005 from 2008 October 2009 February. results show remarkable evolution element overabundances. Measurements magnetic field moment technique several elements reveal presence longitudinal order few hundred gauss both stellar components quadratic...
We present the status of PEPSI, bench-mounted fibre-fed and stabilized "Potsdam Echelle Polarimetric Spectroscopic Instrument" for 2×8.4m Large Binocular Telescope in southern Arizona. PEPSI is under construction at AIP scheduled first light 2009/10. Its ultra-high-resolution mode will deliver an unprecedented spectral resolution approximately R=310,000 high efficiency throughout entire optical/red wavelength range 390-1050nm without need adaptive optics. Besides its polarimetric Stokes IQUV...
Two independent investigations of the atmosphere hot Jupiter HAT-P-12b by two different groups resulted in discrepant solutions. Using broad-band photometry from ground, one study found a flat and featureless transmission spectrum which was interpreted as gray absorption dense cloud coverage. The second made use Hubble Space Telescope (HST) observations Rayleigh scattering at optical wavelengths caused haze. main purpose this work is to find source inconsistency provide feedback prevent...
Context. Eradicating the problems associated with Earth's day-night cycle is mandatory for long and continuous time-series photometry had been achieved either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility offered by a polar location astronomically-qualified site characteristics.