LAUNCHED XTgrid Sandbox: Online spectral analyses with Tlusty or CMFGEN models!

Recent Projects

  • February 05, 2022 1/5

    Orbital and atmospheric parameters of two O-type subdwarf binaries: BD-11° 162 and Feige 80

    A&A, 2022, 658, A122, 22EZZ74T

    Using high-resolution spectra the orbital and atmospheric parameters of BD-11° 162 and Feige 80 have been solved. Masses of the companions and the sdOs were obtained, and the ...

  • February 09, 2023 2/5

    An 18.9-minute Blue Large-Amplitude Pulsator Crossing the "Hertzsprung Gap" of Hot Subdwarfs

    Nature, 2023, Volume 7, 223UMVVTX

    Blue large-amplitude pulsators (BLAPs) represent a new and rare class of hot pulsating stars with unusually large amplitudes and short periods. Up to now, only 24 confirmed BLAPs ...

  • August 23, 2023 3/5

    Unveiling the Evolutionary State of Three B Supergiant Stars: PU Gem, ϵ CMa, and η CMa

    Galaxies, 2023, Vol. 11, issue 5, p. 93.M1DE05

    We aim to combine asteroseismology, spectroscopy, and evolutionary models to establish a comprehensive picture of the evolution of Galactic blue supergiant stars (BSG). To start ...

  • February 09, 2024 4/5

    A seven-Earth-radius helium-burning star inside a 20.5-min detached binary

    Nature Astronomy, 2024, acceptedY75AKG

    Binary evolution theory predicts that the second common envelope (CE) ejection can produce low-mass (0.32 - 0.36 solar mass) subdwarf B (sdB) stars inside ...

  • February 29, 2024 5/5

    The double low-mass white dwarf eclipsing binary system J2102-4145 and its possible evolution

    A&A, 2024, acceptedXG61YQ

    Approximately 150 low-mass white dwarfs, with masses below 0.4 Msun, have been discovered. The majority of these low-mass WDs are observed in binary systems as they cannot be ...


Astroserver is a private, community supported non-profit organization with affordable solutions in research astronomy. The team offers expertise mainly in stellar astrophysics, spectroscopy, non-LTE model atmosphere calculations, assistance with publications and media content production, and help with service observations. These services are similar to the tasks of post-doctoral and graduate researchers. Therefore, our activity can be integrated into the programme of graduate schools and research institutes. To wrap-up: Astroserver is your "occasional post-doc".

The main goal of the Astroserver Team is to provide precise and reliable measurements of stellar atmospheric parameters in a consistent way across the Hertzsprung-Russell Diagram and make it accessible to everyone. The accuracy of these solutions depends on the choice of the model, the quality of input atomic data and observations. Therefore, our Team continuously improves the models and revise the atomic data input by analyzing high quality observations of standard objects. Beyond the main mission the Team is also keen on finding solutions to challenging problems on the frontiers of applied stellar spectroscopy.

Interested researchers: Please consider our services in the budget plan of your grant applications! Upon request we contribute to such proposals free of charge.

Feel free to contact us for more information!

Research Highlights
  • 2017

    Atomic diffusion in the atmosphere of Feige 86

    A re-analysis of the ultraviolet and optical spectra of Feige 86 found large abundances of xenon in its atmosphere. The star shows a rich, sharp-lined peculiar spectrum both in the ultraviolet and the optical, which marks active atomic diffusion processes.

  • 2016

    PB 3877: A new hypervelocity binary

    A team of astronomers at the Friedrich Alexander University, Erlangen-Nürnberg (FAU, Germany) in collaboration with researchers from the California Institute of Technology (Caltech, USA), has discovered a binary star (PB 3877) that is moving nearly at the escape velocity of our Galaxy.

  • 2024

    A seven-Earth-radius helium-burning star inside a 20.5-min detached binary

    Binary evolution theory predicts that the second common envelope (CE) ejection can produce low-mass (0.32 - 0.36 solar mass) subdwarf B (sdB) stars inside ultrashort-orbital-period binary systems. Their helium cores are ignited under nondegenerate conditions. With the orbital decay driven by gravitational-wave (GW) radiation, the minimum orbital periods of detached sdB binaries could be as short as 20 minutes. However, only four sdB binaries with orbital periods ...

  • 2017

    Composite hot subdwarf binaries from UVES

    Hot subdwarf-B (sdB) stars in long-period binaries are found to be on eccentric orbits, even though current binary-evolution theory predicts these objects to be circularised before the onset of Roche-lobe overflow (RLOF). To increase our understanding of binary interaction processes during the RLOF phase, we started a long term observing campain to study wide sdB binaries.


We are presently exploring methods to create a user-friendly, self-service tool for the comprehensive spectral analysis of composite spectra. There are compelling reasons to pursue this direction. Chief among them is the prevalence of stars existing in binary or multiple systems. Binaries, in particular, offer astronomers not only a surplus of information but, in some instances, crucial insights. Yet, acquiring this information comes with its own set of challenges. While analyzing single stars presents its own difficulties, the complexities of binaries and multiple systems make the process more than doubly intricate and laborious.

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