ABSTRACT
We report the discovery of TOI-4641b, a warm Jupiter transiting a rapidly rotating F-type star with a stellar effective temperature of 6560 K. The planet has a radius of 0.73 RJup, a mass ...smaller than 3.87 MJup(3σ), and a period of 22.09 d. It is orbiting a bright star (V=7.5 mag) on a circular orbit with a radius and mass of 1.73 R⊙ and 1.41 M⊙. Follow-up ground-based photometry was obtained using the Tierras Observatory. Two transits were also observed with the Tillinghast Reflector Echelle Spectrograph, revealing the star to have a low projected spin-orbit angle (λ=$1.41^{+0.76}_{-0.76}$°). Such obliquity measurements for stars with warm Jupiters are relatively few, and may shed light on the formation of warm Jupiters. Among the known planets orbiting hot and rapidly rotating stars, TOI-4641b is one of the longest period planets to be thoroughly characterized. Unlike hot Jupiters around hot stars which are more often misaligned, the warm Jupiter TOI-4641b is found in a well-aligned orbit. Future exploration of this parameter space can add one more dimension to the star–planet orbital obliquity distribution that has been well sampled for hot Jupiters.
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 report the discovery of two mini-Neptunes in near 2:1 resonance orbits (\(P=7.610303\) d for HIP 113103 b and \(P=14.245651\) d for HIP 113103 c) around the adolescent K-star HIP 113103 (TIC ...121490076). The planet system was first identified from the TESS mission, and was confirmed via additional photometric and spectroscopic observations, including a \(\sim\)17.5 hour observation for the transits of both planets using ESA CHEOPS. We place \(\leq4.5\) min and \(\leq2.5\) min limits on the absence of transit timing variations over the three year photometric baseline, allowing further constraints on the orbital eccentricities of the system beyond that available from the photometric transit duration alone. With a planetary radius of \(R_{p}=1.829^{+0.096}_{-0.067}\,R_{\oplus}\), HIP 113103 b resides within the radius gap, and this might provide invaluable information on the formation disparities between super-Earths and mini-Neptunes. Given the larger radius \(R_{p}=2.40^{+0.10}_{-0.08}\,R_{\oplus}\) for HIP 113103 c, and close proximity of both planets to HIP 113103, it is likely that HIP 113103 b might have lost (or is still losing) its primordial atmosphere. We therefore present simulated atmospheric transmission spectra of both planets using JWST, HST, and Twinkle. It demonstrates a potential metallicity difference (due to differences in their evolution) would be a challenge to detect if the atmospheres are in chemical equilibrium. As one of the brightest multi sub-Neptune planet systems suitable for atmosphere follow up, HIP 113103 b and HIP 113103 c could provide insight on planetary evolution for the sub-Neptune K-star population.
Despite decades of effort, the mechanisms by which the spin axis of a star and the orbital axes of its planets become misaligned remain elusive. Particularly, it is of great interest whether the ...large spin-orbit misalignments observed are driven primarily by high-eccentricity migration -- expected to have occurred for short-period, isolated planets -- or reflect a more universal process that operates across systems with a variety of present-day architectures. Compact multi-planet systems offer a unique opportunity to differentiate between these competing hypotheses, as their tightly-packed configurations preclude violent dynamical histories, including high-eccentricity migration, allowing them to trace the primordial disk plane. In this context, we report measurements of the sky-projected stellar obliquity (\(\lambda\)) via the Rossiter-McLaughlin effect for two sub-Saturns in multiple-transiting systems: TOI-5126 b (\(\lambda=1\pm 48\,^{\circ}\)) and TOI-5398 b (\(\lambda=-24^{+14}_{-13} \,^{\circ}\)). Both are spin-orbit aligned, joining a fast-growing group of just three other compact sub-Saturn systems, all of which exhibit spin-orbit alignment. Our results strongly suggest that sub-Saturn systems are primordially aligned and become misaligned largely in the post-disk phase through violent dynamical interactions inherent to eccentric migration, as appears to be the case increasingly for other exoplanet populations.
We present an updated characterization of the TOI-1685 planetary system,
which consists of a P$_{\rm{b}}$ = 0.69\,day USP super-Earth planet orbiting a
nearby ($d$ = 37.6\,pc) M2.5V star (TIC ...28900646, 2MASS J04342248+4302148).
This planet was previously featured in two contemporaneous discovery papers,
but the best-fit planet mass, radius, and bulk density values were discrepant
allowing it to be interpreted either as a hot, bare rock or a 50\% H$_{2}$O /
50\% MgSiO$_{3}$ water world. TOI-1685 b will be observed in three independent
JWST cycle two programs, two of which assume the planet is a water world while
the third assumes that it is a hot rocky planet. Here we include a refined
stellar classification with a focus on addressing the host star's metallicity,
an updated planet radius measurement that includes two sectors of TESS data and
multi-color photometry from a variety of ground-based facilities, and a more
accurate dynamical mass measurement from a combined CARMENES, IRD, and MAROON-X
radial velocity data set. We find that the star is very metal-rich (Fe/H
$\simeq$ +0.3) and that the planet is systematically smaller, lower mass, and
higher density than initially reported, with new best-fit parameters of \Rpl =
1.468 $^{+0.050}_{-0.051}$ \Rearth\ and \Mpl = 3.03$^{+0.33}_{-0.32}$ \Mearth.
These results fall in between the previously derived values and suggest that
TOI-1685 b is a hot, rocky, planet with an Earth-like density (\Rhopl = 5.3
$\pm$ 0.8 g cm$^{-3}$, or 0.96 \rhoearth), high equilibrium temperature
(T$_{\rm{eq}}$ = 1062 $\pm$ 27 K) and negligible volatiles, rather than a water
world.
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.
