Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A large sub-Neptune transiting the thick-disk M4V TOI-2406   Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and
are rarer still around those that are metal-poor. However, owing to the large
planet-to-star radius ratio, these planets are highly suitable for atmospheric
study via transmission spectroscopy in the infrared, such as with JWST. Here we
report the discovery and validation of a sub-Neptune orbiting the thick-disk,
mid-M dwarf star TOI-2406. We first infer properties of the host star by
analysing the star's near-infrared spectrum, spectral energy distribution, and
Gaia parallax. We use multi-band photometry to confirm that the transit event
is on-target and achromatic, and we statistically validate the TESS signal as a
transiting exoplanet. We then determine physical properties of the planet
through global transit modelling of the TESS and ground-based time-series data.
We determine the host to be a metal-poor M4V star, located at a distance of 56
pc, with a sub-solar metallicity $(\mathrm{[Fe/H] = -0.38 \pm 0.07})$, and a
member of the thick disk. The planet is a relatively large sub-Neptune for the
M-dwarf planet population, with $\mathrm{R_p = 2.94 \pm 0.17}
\mathrm{R_\oplus}$ and $\mathrm{P = 3.077}$ d, producing transits of 2% depth.
We note the orbit has a non-zero eccentricity to 3$\mathrm{\sigma}$, prompting
questions about the dynamical history of the system. This system is an
interesting outcome of planet formation and presents a benchmark for
large-planet formation around metal-poor, low-mass stars. The system warrants
further study, in particular radial velocity follow-up to determine the planet
mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good
target for future atmospheric study through transmission spectroscopy,
particularly in the category of warm sub-Neptunes.

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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int