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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 ...


Mission

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
  • 2020

    TESS observations of the interesting pulsating subdwarf B star CD-28° 1974

    From TESS observations we have discovered CD-28° 1974 to be a pulsating subdwarf B star which has an unusual gravity(g)-mode asymptotic sequence indicating that CD-28° 1974’s structure is somewhat different from typical sdBV stars.

  • 2023

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

    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 such an investigation, we selected three BSG candidates for our analysis: HD 42087 (PU Gem), HD 52089 (ϵ CMa), and HD 58350 (η CMa). These stars show pulsations and were suspected to be in an evolutionary stage either preceding or succeding the red supergiant (RSG) stage.

  • 2017

    A FEROS survey of hot subdwarf stars

    We have initiated a small survey of twenty hot subdwarfs using the Fiber-fed Extended Range Optical Spectrograph (FEROS) and the 2.2-m telescope at La Silla. The sample includes apparently single objects as well as hot subdwarfs paired with a bright, unresolved companion extracted from our GALEX catalogue of hot subdwarf stars (Vennes et al., 2011; Nemeth et al., 2012). As expected (Kawka et al., 2015; Kupfer et al., 2015), the fraction of radial velocity variables ...

  • 2022

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

    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 photospheric chemical abundances of the main-sequence stars for elements with available lines in the optical range have been derived.

Milestones

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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