Abstract:
Asteroseismic analysis of stars using space mission data, such as the transiting exoplanet survey
satellite (TESS) allows us to derive accurate fundamental parameters of stars. Barium and CH stars are
believed to be in binary systems with a now invisible white dwarf companion. Knowledge of accurate
fundamental parameters of these stars is essential to understand the origin of the peculiar abundance patterns
observed in these stars. In this work, we have presented estimates of the fundamental parameters derived
using asteroseismic analysis for three objects HD 33409, HD 20084 and HD 66812 selected from barium and
CH stars catalogs. We have analysed the TESS photometric data using lightkurve Python package employing
the aperture photometry, derived the asteroseismic parameters, and using scaling relations, calculated the
stellar parameters. We have estimated power excess ðmmaxÞ at 44:50 0:50 lHz and large frequency separation ðDmÞ to be 4:77 0:10 lHz for HD 33409. These two values for HD 20084 and HD 66812 are
(48:50 0:50 lHz, 4:88 0:10 lHz) and (22:50 0:50 lHz, 2:47 0:10 lHz), respectively. Our results
showed that the primary component is a giant branch star with mass, radius, surface gravity and luminosity
logðL=L) of 1:46 0:07 M, 10:54 0:12 R, 2:56 0:01 dex and 1.71, respectively, for HD 33409.
These values for HD 20084 and HD 66812 are (1:84 0:07 M, 11:21 0:12 R, 2:60 0:01 dex, 1.87)
and (2:78 0:07 M, 20:26 0:12 R, 2:27 0:01 dex, 2.37), respectively. The estimated stellar parameters obtained from asteroseismology are compared with literature values whenever possible and found to be
in fair agreement with spectroscopic estimates. Stellar mass derived using parallax method is also found to be
in close agreement in the case of HD 33409 and HD 20084. While the parallax method gives mass value of 4
M for HD 66812, the asteroseismic estimate is much smaller 2.78 M for this object.
