Skip to content
DraconiticResearch
Search Sources API
197,768 studies31 sourcesUpdated 53 min ago
PreprintCC BY 4.0arXiv

The study of AF And. I. Hydrogen abundance constraints and dynamically-consistent wind model of the hot state

  • E. O. Dedov
  • A. E. Kostenkov
  • A. S. Vinokurov
  • A. N. Sarkisyan
Open at sourcePDFDOICite

Abstract

This paper starts a series of works devoted to an in-depth study of luminous blue variable AF And in the M31 galaxy. Here we present the results of non-LTE modelling of the star in a hot state with CMFGEN code. In addition to the β-velocity law, widely used in the analysis of stellar atmospheres, we used a velocity distribution obtained from the balance of radial forces in the wind, including centrifugal forces for several models. Such a dynamically consistent approach reduces the parameter space during modelling and, in addition, allows us to estimate the current stellar mass whose inner hydrostatic layers are obscured by a dense wind that contaminates the absorption profiles. Based on our modelling we estimate the parameters of AF And as follows: luminosity L ≈ 6.5×105 L⊙, mass loss rate Ṁ ≈ 3×10−5 M⊙ yr−1, terminal velocity v∞ ≈ 300 km s−1 and effective temperature Teff ≈ 17 kK. modelling of the hot state of AF And is of particular interest due to the possibility to place constraints on the ratio of hydrogen and helium abundances for further use in constructing models of the cold state of this star. We conclude that the current hydrogen mass fraction in the wind lies in the range from $20$ to $30$ per cent. Self-consistent modelling gives the current mass M* estimation in the range 15.6 − 17.7 M⊙. By employing evolutionary tracks, we were able to estimate the initial stellar mass as M*, init ≈ 50 M⊙.

Versions

Related

  1. LHAASO Constraints on New-Source Cosmic Rays:Abundance Scenarios and Injection Spectral Indices
    Xu-Lin Dong, Pei-Pei Zhang, Qi-Ling Chen +2
    arXivPreprintarXiv licenceFull textHigh-energy astrophysicsarXiv
  2. No Detectable One-halo Galactic Conformity Signal with Halo-mass Estimates Consistent with Weak-lensing Constraints
    Dingyi Zhao, Yingjie Peng, Luis C. Ho +17
    arXivPreprintarXiv licenceFull textGalaxiesarXiv
  3. The hydrogen isotopic composition and content of the ureilite parent body: constraints from new ungrouped achondrites
    B.G. Rider-Stokes, A. Stephant, M. Nottingham +7
    Geochimica et Cosmochimica ActaPeer-reviewedCC BY 4.0Full textPlanetary science & exoplanetsHAL
  4. An Analytical Toy Equation of State for Neutron Stars Consistent with Current Observations
    Tian-Shun Chen, Xiao-Ding Zhou, Kilar Zhang
    arXivPreprintarXiv licenceFull textHigh-energy astrophysicsGravitation & general relativityarXiv
  5. An Analytical Toy Equation of State for Neutron Stars Consistent with Current Observations
    Tian-Shun Chen, Xiao-Ding Zhou, Kilar Zhang
    The Astrophysical JournalPeer-reviewedCC BY 4.0Full textHigh-energy astrophysicsCrossref

Cite

BibTeXRIS
BibTeX
@misc{dedov2026study,
  title = {{The study of AF And. I. Hydrogen abundance constraints and dynamically-consistent wind model of the hot state}},
  author = {E. O. Dedov and A. E. Kostenkov and A. S. Vinokurov and A. N. Sarkisyan},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.16794},
  eprint = {2609.16794},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.16794},
  note = {CC BY 4.0},
}
RIS
TY  - UNPB
TI  - The study of AF And. I. Hydrogen abundance constraints and dynamically-consistent wind model of the hot state
AU  - E. O. Dedov
AU  - A. E. Kostenkov
AU  - A. S. Vinokurov
AU  - A. N. Sarkisyan
PY  - 2026
DA  - 2026/09/15
PB  - arXiv
DO  - 10.48550/arxiv.2609.16794
UR  - https://arxiv.org/abs/2609.16794
AB  - This paper starts a series of works devoted to an in-depth study of luminous blue variable AF And in the M31 galaxy. Here we present the results of non-LTE modelling of the star in a hot state with CMFGEN code. In addition to the β-velocity law, widely used in the analysis of stellar atmospheres, we used a velocity distribution obtained from the balance of radial forces in the wind, including centrifugal forces for several models. Such a dynamically consistent approach reduces the parameter space during modelling and, in addition, allows us to estimate the current stellar mass whose inner hydrostatic layers are obscured by a dense wind that contaminates the absorption profiles. Based on our modelling we estimate the parameters of AF And as follows: luminosity L ≈ 6.5×10^5 L_⊙, mass loss rate Ṁ ≈ 3×10^−5 M_⊙ yr^−1, terminal velocity v_∞ ≈ 300 km s^−1 and effective temperature T_eff ≈ 17 kK. modelling of the hot state of AF And is of particular interest due to the possibility to place constraints on the ratio of hydrogen and helium abundances for further use in constructing models of the cold state of this star. We conclude that the current hydrogen mass fraction in the wind lies in the range from $20$ to $30$ per cent. Self-consistent modelling gives the current mass M_* estimation in the range 15.6 − 17.7 M_⊙. By employing evolutionary tracks, we were able to estimate the initial stellar mass as M_*, init ≈ 50 M_⊙.
ER  -