Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star   We present the discovery and spectroscopy of HIP 75056Ab, a companion
directly imaged at a very small separation of 0.125 arcsec to an A2V star in
the Scorpius-Centaurus OB2 association. Our observations utilized VLT/SPHERE
between 2015$-$2019, enabling low-resolution spectroscopy (0.95$-$1.65 $\mu
m$), dual-band imaging (2.1$-$2.25 $\mu m$), and relative astrometry over a
four-year baseline. HIP 75056Ab is consistent with spectral types in the range
of M6$-$L2 and $T_{\rm eff}\sim$ 2000$-$2600 K. A comparison of the companion's
brightness to evolutionary tracks suggests a mass of $\sim$20$-$30 M$_{Jup}$.
The astrometric measurements are consistent with an orbital semi-major axis of
$\sim$15$-$45 au and an inclination close to face-on (i$\lesssim$35$^o$). In
this range of mass and orbital separation, HIP 75056Ab is likely at the
low-mass end of the distribution of companions formed via disk instability,
although a formation of the companion via core accretion cannot be excluded.
The orbital constraints are consistent with the modest eccentricity values
predicted by disk instability, a scenario that can be confirmed by further
astrometric monitoring. HIP 75056Ab may be utilized as a low-mass atmospheric
comparison to older, higher-mass brown dwarfs, and also to young giant planets.
Finally, the detection of HIP 75056Ab at 0.125 arcsec represents a milestone in
detecting low-mass companions at separations corresponding to the habitable
zones of nearby Sun-like stars.

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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
3
The categories of this paper are: physics
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The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: econ
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con