Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetospheric accretion in the intermediate-mass T Tauri star HQ Tau   Context. Classical T Tauri stars (cTTs) are pre-main sequence stars
surrounded by an accretion disk. They host a strong magnetic field, and both
magnetospheric accretion and ejection processes develop as the young magnetic
star interacts with its disk. Studying this interaction is a major goal toward
understanding the properties of young stars and their evolution. Aims. The goal
of this study is to investigate the accretion process in the young stellar
system HQ Tau, an intermediate-mass T Tauri star (1.9 M$_{\odot}$). Methods.
The time variability of the system is investigated both photometrically, using
Kepler-K2 and complementary light curves, and from a high-resolution
spectropolarimetric time series obtained with ESPaDOnS at CFHT. Results. The
quasi-sinusoidal Kepler-K2 light curve exhibits a period of 2.424 d, which we
ascribe to the rotational period of the star. The radial velocity of the system
shows the same periodicity, as expected from the modulation of the photospheric
line profiles by surface spots. A similar period is found in the red wing of
several emission lines (e.g., HI, CaII, NaI), due to the appearance of inverse
P Cygni components, indicative of accretion funnel flows. Signatures of
outflows are also seen in the line profiles, some being periodic, others
transient. The polarimetric analysis indicates a complex, moderately strong
magnetic field which is possibly sufficient to truncate the inner disk close to
the corotation radius, r$_{cor}$ $\sim$3.5 R$_{\star}$. Additionally, we report
HQ Tau to be a spectroscopic binary candidate whose orbit remains to be
determined. Conclusions. The results of this study expand upon those previously
reported for low-mass T Tauri stars, as they indicate that the magnetospheric
accretion process may still operate in intermediate-mass pre-main sequence
stars, such as HQ Tau.

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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph