Abstract:
We present a detailed study of Maia type variable star, TIC 202431888 observed by
the TESS satellite (Ricker et al., 2015) for the first time in literature. A new group
of variable stars with late B or early A-type characteristics was initially proposed
based on radial velocity observations of the prototype star, Maia, which is a member
of the Pleiades star cluster as indicated by Struve (1955) and by Struve et al. (1957).
During the following years, several studies also identified a short list of possible Maia
candidates, but they were later classified into different variability groups. Maia
variables are characterized by multiple high frequencies that occur between the red
edge of the Cephei and the blue edge of the Scuti instability strips. It is
possible that these stars are being driven by a pulsating mechanism that is not
yet understood, and the high frequencies observed in late B-type stars still lack an
explanation based on our current knowledge. However, stellar variability is being
rediscovered by recent space missions like TESS through analysing unprecedented
data sets, allowing for the detection of oscillations with very low amplitudes and
they have been promising in solving the classification puzzle of Maia phenomenon
among B-type stars.
This study aims to examine common characteristics of Maia variables (MAIA) to
investigate comparable or distinct features in the star TIC 202431888 listed among
the classified Maia stars by Balona & Ozuyar (2020). For this reason, the TESS pho-
tometry and high-dispersion ground-based spectroscopy were used. Spectroscopic
observations were obtained with the 2-m RCC telescope at Rozhen, Bulgaria. From
the spectroscopic observations, the atmospheric parameters, the projected rotational
velocity v sin i, and chemical abundance of selected elements of TIC 202431888 were
determined as well as the evolutionary track of the star in the HR diagram has
been presented. The frequency analysis of the TESS photometry resulted in the
detection of the two highest peaks at f 1 = 19.32 d 1 and f 2 = 22.10 d 1 , along with
a few combinations and harmonics. Our results indicate that TIC 202431888 is a
Maia-type variable star with low amplitude and high frequency values exceeding 5
d 1 , and its stellar parameters are in line with those observed between Scuti and
B-type variables, which are classified as MAIAU by Balona (2023a). Also, we are in
agreement that MAIA should continue to refer to these stars by their observed dis-
tinctive features, which are contrary to current models, until accurate classification
distinctions for instability regions are established (Balona, 2023a)
