Are Am stars and hot-Jupiter planets related?. (arXiv:2209.14257v1 [astro-ph.SR])

Are Am stars and hot-Jupiter planets related?. (arXiv:2209.14257v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Saffe_C/0/1/0/all/0/1">C. Saffe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alacoria_J/0/1/0/all/0/1">J. Alacoria</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miquelarena_P/0/1/0/all/0/1">P. Miquelarena</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petrucci_R/0/1/0/all/0/1">R. Petrucci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arancibia_M/0/1/0/all/0/1">M. Jaque Arancibia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Angeloni_R/0/1/0/all/0/1">R. Angeloni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martioli_E/0/1/0/all/0/1">E. Martioli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Flores_M/0/1/0/all/0/1">M. Flores</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jofre_E/0/1/0/all/0/1">E. Jofre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collado_A/0/1/0/all/0/1">A. Collado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gunella_F/0/1/0/all/0/1">F. Gunella</a>

Am stars are often components of short-period binary systems, where tidal
interactions would result in low rotational velocities and help to develop the
chemical peculiarities observed. However, the origin of single Am stars and Am
stars that belong to wide binary systems is unclear. There is very recent
evidence of an Am star hosting a hot-brown dwarf likely synchronized and other
possible Am stars hosting hot-Jupiter planets. We wonder if these hot-low mass
companions could play a role in the development of an Am star, that is to say,
if they could help to mitigate the “single Am” problem. We studied a sample of
19 early-type stars, 7 of them hosting hot-brown dwarfs and 12 of them hosting
hot-Jupiter planets. We detected 4 Am stars in our sample (KELT-19A, KELT-17,
HATS-70 and TOI-503) and 2 possible Am stars (TOI-681 and HAT-P-69). In
particular, we detected the new Am star HATS-70 which hosts a hot-brown dwarf,
and rule out this class for the hot-Jupiter host WASP-189, both showing
different composition than previously reported. We estimated the incidence of
Am stars within stars hosting hot-brown dwarfs (50-75%) and within stars
hosting hot-Jupiters (20-42%). The incidence of Am stars hosting hot-brown
dwarfs resulted higher than the frequency of Am stars in general. This would
imply that the presence of hot-brown dwarfs could play a role in the
development of Am stars and possibly help to mitigate the “single Am” problem,
different to the case of hot-Jupiter planets. Notably, these results would also
indicate that the search for hot-brown dwarfs may be benefited by targeting
single Am stars or Am stars in wide binary systems. We encourage the analysis
off additional early-type stars hosting hot-companions in order to improve the
significance of the initial trends found here. [abridged]

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