ABSTRACT
We present the confirmation of a hot super-Neptune with an exterior Neptune companion orbiting a bright (V = 10.1 mag) F-dwarf identified by the Transiting Exoplanet Survey Satellite ...(TESS). The two planets, observed in sectors 45, 46, and 48 of the TESS extended mission, are $4.74_{-0.14}^{+0.16}$ and $3.86_{-0.16}^{+0.17}$ R⊕ with $5.4588385_{-0.0000072}^{+0.0000070}$ and $17.8999_{-0.0013}^{+0.0018}$ d orbital periods, respectively. We also obtained precise space-based photometric follow-up of the system with ESA’s CHaracterising ExOplanets Satellite to constrain the radius and ephemeris of TOI-5126 b. TOI-5126 b is located in the ‘hot Neptune Desert’ and is an ideal candidate for follow-up transmission spectroscopy due to its high-predicted equilibrium temperature (Teq = ${1442}_{-40}^{+46}$ K) implying a cloud-free atmosphere. TOI-5126 c is a warm Neptune (Teq = $971_{-27}^{+31}$ K) also suitable for follow-up. Tentative transit timing variations have also been identified in analysis, suggesting the presence of at least one additional planet, however this signal may be caused by spot-crossing events, necessitating further precise photometric follow-up to confirm these signals.
We present the confirmation of a hot super-Neptune with an exterior Neptune
companion orbiting a bright (V = 10.1 mag) F-dwarf identified by the
$\textit{Transiting Exoplanet Survey Satellite}$ ...($\textit{TESS}$). The two
planets, observed in sectors 45, 46 and 48 of the $\textit{TESS}$ extended
mission, are $4.74^{+0.16}_{-0.14}$ $R_{\oplus}$ and $3.86^{+0.17}_{-0.16}$
$R_{\oplus}$ with $5.4588385^{+0.0000070}_{-0.0000072}$ d and
$17.8999^{+0.0018}_{-0.0013}$ d orbital periods, respectively. We also obtained
precise space based photometric follow-up of the system with ESAs
$\textit{CHaracterising ExOplanets Satellite}$ ($\textit{CHEOPS}$) to constrain
the radius and ephemeris of TOI-5126 b. TOI 5126 b is located in the "hot
Neptune Desert" and is an ideal candidate for follow-up transmission
spectroscopy due to its high predicted equilibrium temperature ($T_{eq} =
1442^{+46}_{-40}$ K) implying a cloud-free atmosphere. TOI-5126 c is a warm
Neptune ($T_{eq}= 971^{+31}_{-27}$ K) also suitable for follow-up. Tentative
transit timing variations (TTVs) have also been identified in analysis,
suggesting the presence of at least one additional planet, however this signal
may be caused by spot-crossing events, necessitating further precise
photometric follow-up to confirm these signals.
We present the confirmation of a hot super-Neptune with an exterior Neptune companion orbiting a bright (V = 10.1 mag) F-dwarf identified by the \(\textit{Transiting Exoplanet Survey Satellite}\) ...(\(\textit{TESS}\)). The two planets, observed in sectors 45, 46 and 48 of the \(\textit{TESS}\) extended mission, are \(4.74^{+0.16}_{-0.14}\) \(R_{\oplus}\) and \(3.86^{+0.17}_{-0.16}\) \(R_{\oplus}\) with \(5.4588385^{+0.0000070}_{-0.0000072}\) d and \(17.8999^{+0.0018}_{-0.0013}\) d orbital periods, respectively. We also obtained precise space based photometric follow-up of the system with ESAs \(\textit{CHaracterising ExOplanets Satellite}\) (\(\textit{CHEOPS}\)) to constrain the radius and ephemeris of TOI-5126 b. TOI 5126 b is located in the "hot Neptune Desert" and is an ideal candidate for follow-up transmission spectroscopy due to its high predicted equilibrium temperature (\(T_{eq} = 1442^{+46}_{-40}\) K) implying a cloud-free atmosphere. TOI-5126 c is a warm Neptune (\(T_{eq}= 971^{+31}_{-27}\) K) also suitable for follow-up. Tentative transit timing variations (TTVs) have also been identified in analysis, suggesting the presence of at least one additional planet, however this signal may be caused by spot-crossing events, necessitating further precise photometric follow-up to confirm these signals.
