Search Publications
Detecting stellar activity cycles in p-mode travel times. Proof of concept using SOHO/VIRGO solar observations
Gizon, L.; Vasilyev, V.
Context. The 11 yr solar cycle is known to affect the global modes of solar acoustic oscillations. In particular, p mode frequencies increase with solar activity.
Aims: We propose a new method to detect the solar cycle from the p-mode autocorrelation function, and we validate this method using VIRGO/SPM photometric time series from solar cycl…
A variety of binary targets for small telescopes
Miroshnichenko, A. S.; Zharikov, S.; Danford, S. +10 more
Results are reviewed of a long-term program of binary systems observing since 2013 at the 0.81 m telescope of the Three College Observatory in North Carolina, USA, with an échelle spectrograph at a medium spectral resolution. The target list includes recognized and suspected binary systems with normal stars (no spectral lines in emission), classic…
The Gaia-ESO Survey: Calibrating the lithium-age relation with open clusters and associations. II. Expanded cluster sample and final membership selection
Prusti, T.; Gilmore, G.; Montes, D. +25 more
Context. The Li abundance observed in pre-main sequence and main sequence late-type stars is strongly age-dependent, but also shows a complex pattern depending on several parameters, such as rotation, chromospheric activity, and metallicity. The best way to calibrate these effects, and with the aim of studying Li as an age indicator for FGK stars,…
Searching for triple systems unbound by supernovae
Kochanek, Christopher S.; Barboza, Karina
A large fraction of massive stars are found in higher order systems where the presence of a tertiary may significantly modify the system's evolution. In particular, it can lead to increased numbers of compact object binaries and accelerate their mergers with important implications for gravitational wave observations. Using Gaia, we constrain the n…
Near-infrared Spectroscopy for Remote Sensing of Porosity, Density, and Cubicity of Crystalline and Amorphous H2O Ices in Astrophysical Environments
Tonauer, Christina M.; Köck, Eva-Maria; Henn, Raphael +8 more
We present laboratory spectra of pure amorphous and crystalline H2O ices in the near-infrared (NIR, 1–2.5 µm/10,000–4000 cm‑1) at 80–180 K. The aim of this study is to provide spectroscopic reference data that allow remotely accessing ice properties for icy objects such as icy moons, cometary ice, or Saturn rings. Speci…
The possible dual nature of the asteroid (12499) 1998 FR47
Borisov, G.; Kostov, A.; Todorović, N. +2 more
We present the R-band lightcurves of the Flora family asteroid (12499) 1998 FR47, obtained in 2022 at two different astronomical sites: Bulgarian National Astronomical Observatory Rozhen (MPC Code 071) and Astronomical Station Vidojevica (MPC Code C89). The quadramodal lightcurves reveal a rotation period of 6.172±0.003 h and an amplitude of about…
Directional discontinuities in the inner heliosphere from Parker Solar Probe and Solar Orbiter observations
Szabo, A.; Opitz, A.; Nemeth, Z. +5 more
Context. Directional discontinuities (DDs) are common structures in the solar wind plasma and are among the most important discontinuities besides shock waves. The Parker Solar Probe and Solar Orbiter spacecraft currently provide whole new insight into the inner heliosphere in spatial coverage and timescales. Aims. We search for DDs and classify t…
Hot subdwarf wind models with accurate abundances. II. Helium-dominated merger products CD-46 8926 and CD-51 11879
Krtička, J.; Vučković, M.; Janík, J. +3 more
Context. Helium-dominated subdwarfs are core helium burning stars stripped of their envelope. The nuclear evolution of these stars alters surface abundances. Modified abundances impact the strength of the stellar wind.
Aims: We aim to understand the influence of modified surface abundances on the strength of the stellar wind in the helium-dom…
Trials and Tribulations in the Reanalysis of KELT-24 b: A Case Study for the Importance of Stellar Modeling
Vanderburg, Andrew; Stassun, Keivan G.; Wittenmyer, Robert A. +21 more
We present a new analysis of the KELT-24 system, comprising a well-aligned hot Jupiter, KELT-24 b, and a bright (V = 8.3), nearby (d = 96.9 pc) F-type host star. KELT-24 b was independently discovered by two groups in 2019, with each reporting best-fit stellar parameters that were notably inconsistent. Here, we present three independent analyses o…
Improved Empirical Backgrounds for JWST NIRISS Image/Wide-field Slitless Spectroscopy Data Reduction
Momcheva, Ivelina G.; Hviding, Raphael E.; Clarke, Leonardo
The Near Infrared Imager and Slitless Spectrograph (NIRISS) on the James Webb Space Telescope (JWST) is a versatile instrument for collecting imaging and wide-field slitless spectroscopy (WFSS) data for surveys of galaxy clusters, emission-line galaxies, stellar populations, and more. Dispersed zodiacal light imprints distinct structures on space-…