Search Publications
Propagating brightenings in small loop-like structures in the quiet-Sun corona: Observations from Solar Orbiter/EUI
Teriaca, Luca; Solanki, Sami K.; Schühle, Udo +6 more
Brightenings observed in solar extreme-ultraviolet images are generally interpreted as signatures of micro- or nanoflares occurring in the transition region or at coronal temperatures. Recent observations with the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter have revealed the smallest of such brightenings (called campfires) in the quiet…
Asteroseismology of evolved stars to constrain the internal transport of angular momentum. IV. Internal rotation of Kepler-56 from an MCMC analysis of the rotational splittings
Buldgen, G.; Khan, S.; Eggenberger, P. +4 more
Context. The observations of global stellar oscillations of post-main-sequence stars by space-based photometry missions have allowed us to directly determine their internal rotation. These constraints have pointed towards the existence of angular momentum transport processes not accounted for in theoretical models. Constraining the properties of t…
Semi-regular red giants as distance indicators. I. The period-luminosity relations of semi-regular variables revisited
Mowlavi, N.; Lebzelter, T.; Trabucchi, M.
Context. Semi-regular variables (SRVs) are similar to Miras in brightness, and they also follow one or more period-luminosity relations (PLRs), though not necessarily the same one as Miras. As potential standard candles they are more challenging than Miras because of their smaller variability amplitudes and less regular light curves, but they are …
Milky Way archaeology using RR Lyrae and type II Cepheids. I. The Orphan stream in 7D using RR Lyrae stars
Lemasle, B.; Thévenin, F.; Altavilla, G. +19 more
We present a chemo-dynamical study of the Orphan stellar stream using a catalog of RR Lyrae pulsating variable stars for which photometric, astrometric, and spectroscopic data are available. Employing low-resolution spectra from the Sloan Digital Sky Survey (SDSS), we determined line-of-sight velocities for individual exposures and derived the sys…
TITANS metal-poor reference stars. I. Accurate effective temperatures and surface gravities for dwarfs and subgiants from 3D non-LTE Hα profiles and Gaia parallaxes
Smiljanic, R.; da Silva, A. R.; Giribaldi, R. E. +1 more
Context. Several large stellar spectroscopic surveys are producing enormous amounts of data that can be used to determine stellar atmospheric parameters and chemical abundances. Nonetheless, the accuracy achieved in the derived astrophysical parameters is still insufficient, mainly because of the paucity of adequate calibrators, particularly in th…
New mercury-manganese stars and candidates from LAMOST DR4
Paunzen, E.; Bernhard, K.; Hümmerich, S.
Aims: The present work presents our efforts at identifying new mercury-manganese (HgMn/CP3) stars using spectra obtained with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST).
Methods: Suitable candidates were searched for among pre-selected early-type spectra from LAMOST DR4 using a modified version of the MKCLASS …
Coherent radio emission from a population of RS Canum Venaticorum systems
Callingham, J. R.; Shimwell, T. W.; Vedantham, H. K. +5 more
Coherent radio emission from stars can be used to constrain fundamental coronal plasma parameters, such as plasma density and magnetic field strength. It is also a probe of chromospheric and magnetospheric acceleration mechanisms. Close stellar binaries, such as RS Canum Venaticorum (RS CVn) systems, are particularly interesting as their heightene…
A global view on star formation: the GLOSTAR Galactic plane survey. III. 6.7 GHz methanol maser survey in Cygnus X
Beuther, Henrik; Wyrowski, Friedrich; Gong, Yan +16 more
The Cygnus X complex is covered by the Global View of Star Formation in the Milky Way (GLOSTAR) survey, an unbiased radio-wavelength Galactic plane survey, in 4-8 GHz continuum radiation and several spectral lines. The GLOSTAR survey observed the 6.7 GHz transition of methanol (CH3OH), an exclusive tracer of high-mass young stellar obje…
ESPRESSO mass determination of TOI-263b: an extreme inhabitant of the brown dwarf desert
Mustill, A. J.; Zapatero Osorio, M. R.; Zechmeister, M. +8 more
The TESS mission has reported a wealth of new planetary systems around bright and nearby stars amenable for detailed characterizations of planet properties and atmospheres. However, not all interesting TESS planets orbit around bright host stars. TOI-263 b is a validated ultra-short-period substellar object in a 0.56-day orbit around a faint (V = …
Transition from coherent cores to surrounding cloud in L1688
Caselli, Paola; Rosolowsky, Erik; Kirk, Helen +8 more
Context. Stars form in cold dense cores showing subsonic velocity dispersions. The parental molecular clouds display higher temperatures and supersonic velocity dispersions. The transition from core to cloud has been observed in velocity dispersion, but temperature and abundance variations are unknown.
Aims: We aim to measure the temperature …