TOI-5005 b: A super-Neptune in the savanna near the ridge
The Neptunian desert and savanna have been recently found to be separated by a ridge, an overdensity of planets in the $\simeq$3-5 days period range. These features are thought to be shaped by dynamical and atmospheric processes. However, their relative roles are not yet well understood. We intend t...
Saved in:
Main Authors | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
---|---|
Format | Journal Article |
Language | English |
Published |
26.09.2024
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The Neptunian desert and savanna have been recently found to be separated by
a ridge, an overdensity of planets in the $\simeq$3-5 days period range. These
features are thought to be shaped by dynamical and atmospheric processes.
However, their relative roles are not yet well understood. We intend to confirm
and characterise the super-Neptune TESS candidate TOI-5005.01, which orbits a
moderately bright (V = 11.8) solar-type star (G2 V) with an orbital period of
6.3 days. We confirm TOI-5005 b to be a transiting super-Neptune with a radius
of $R_{\rm p}$ = $6.25\pm 0.24$ $\rm R_{\rm \oplus}$ ($R_{\rm p}$ = $0.558\pm
0.021$ $\rm R_{\rm J}$) and a mass of $M_{\rm p}$ = $32.7\pm 5.9$ $\rm
M_{\oplus}$ ($M_{\rm p}$ = $0.103\pm 0.018$ $\rm M_{\rm J}$), which corresponds
to a mean density of $\rho_{\rm p}$ = $0.74 \pm 0.16$ $\rm g \, cm^{-3}$. Our
internal structure modelling indicates that the overall metal mass fraction is
well constrained to a value slightly lower than that of Neptune and Uranus
($Z_{\rm planet}$ = $0.76^{+0.04}_{-0.11}$). We also estimated the present-day
atmospheric mass-loss rate of TOI-5005 b but found contrasting predictions
depending on the choice of photoevaporation model. At a population level, we
find statistical evidence ($p$-value = $0.0092^{+0.0184}_{-0.0066}$) that
planets in the savanna such as TOI-5005 b tend to show lower densities than
planets in the ridge, with a dividing line around 1 $\rm g \, cm^{-3}$, which
supports the hypothesis of different evolutionary pathways populating both
regimes. TOI-5005 b is located in a key region of the period-radius space to
study the transition between the Neptunian ridge and the savanna. It orbits the
brightest star of all such planets, which makes it a target of interest for
atmospheric and orbital architecture observations that will bring a clearer
picture of its overall evolution. |
---|---|
DOI: | 10.48550/arxiv.2409.18129 |