Chemical abundances and doppler imaging of the Ap Si/He-wk star HD 100357

Abstract

We present the results of time-resolved photometry, abundance analysis and Doppler imaging of an Ap star, HD 100357. The {\it TESS} photometry revealed rotational modulation with a period of 1.6279247 days. Upon inspecting the residuals after removing the rotational period and its harmonics, we found additional frequencies around 15.8054 d${}^{-1}$ which we later confirmed with ground-based observations as originating from a nearby star. Using high-resolution spectroscopy, we identified HD 100357 as an Ap Si/He-wk star exhibiting rotational modulation caused by surface abundance spots. The stellar parameters of HD 100357 were determined as $T_{\mathrm{eff}}$ = 11,850 K, $\log g$ = 4.57, $\upsilon \sin i$ = 60 km\,s${}^{-1}$, and an inclination angle $i$ = 72${}^{\circ }$. The detailed abundance analysis revealed strongly overabundant stratified silicon, an overabundance of iron-peak elements and rare earth elements combined with remarkably deficient helium. Mapping of Fe and Cr abundances revealed the existence of ring-shaped regions with a lower concentration of the elements. Their geometry might reflect the orientation of the hypothetical magnetic field of the star, oriented $\sim$90${}^{\circ }$ to the rotational axis. HD 100357, with its strong chemical peculiarities and indications of possible magnetic fields, represents an interesting candidate for follow-up spectropolarimetric observations aimed at investigating its magnetic field topology and stellar activity.

14 pages, 13 figures, Published by MNRAS

References in corpus (28)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Gaia Data Release 3: Summary of the content and survey properties
• The Transiting Exoplanet Survey Satellite
• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
• The Hipparcos-Gaia Catalog of Accelerations: Gaia EDR3 Edition
• Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs
• Updated Gaia-2MASS 3D maps of Galactic interstellar dust
• Three-dimensional extinction maps: Inverting inter-calibrated extinction catalogues
• Chemically peculiar stars and their temperature calibration
• Magnetic field topology of the unique chemically peculiar star CU Virginis
• Hyperfine Splitting in the VALD Database of Spectral-line Parameters
• Rare-earth elements in the atmosphere of the magnetic chemically peculiar star HD 144897. New classification of the Nd III spectrum
• Revised instability domains of SPB and beta Cephei stars
• prose: A Python framework for modular astronomical images processing
• Doppler imaging of chemical spots on magnetic Ap/Bp stars. Numerical tests and assessment of systematic errors
• The CubeSpec space mission. I. Asteroseismology of massive stars from time series optical spectroscopy: science requirements and target list prioritisation
• New and improved rotational periods of magnetic CP stars from ASAS-3, KELT and MASCARA data
• Visual and ultraviolet flux variability of the bright CP star $\theta$ Aur
• High-resolution Spectroscopy and Spectropolarimetry of Selected Delta Scuti Pulsating Variables
• Study of Chemically Peculiar Stars-I : High-resolution Spectroscopy and K2 Photometry of Am Stars in the Region of M44
• Surface structure of 45 Hercules: An otherwise unremarkable Ap star with a surprisingly weak magnetic field
• Magnetic field topology, chemical spot distributions and photometric variability of the Ap star phi Draconis
• SALT spectroscopy of evolved massive stars
• HD 60431, the CP2 star with the shortest rotational period -- Physical parameters and period analysis
• The magnetic field of the chemically peculiar star V352Peg
• Large Halloween Asteroid at Lunar Distance
• HD 34736: An intensely magnetised double-lined spectroscopic binary with rapidly-rotating chemically peculiar B-type components

Cited by in corpus (2)

• Unveiling the Variability and Chemical Composition of AL Col
• High-precision K2/TESS Photometry and HERMES Spectroscopy of Four Bright Field Stars