We present a joint analysis of TESS photometry and MINERVA-Australis radial velocity data for five long-period eclipsing binary systems with late-F to early-G primaries: TIC 28051929, TIC 49899799, TIC 89045042, TIC 410314066, and TIC 446872386. All systems host early-to late-M dwarf companions that lie in 'tropical' orbits (P similar to 7-30 d) with eccentricities ranging from nearly circular to significantly eccentric (e similar to 0.37). Sky-projected obliquities are derived for each system using a classical analysis of the radial velocity perturbations produced by the Rossiter-McLaughlin effect. Among the five systems, TIC 28051929 stands out as clearly misaligned, with a measured sky-projected obliquity of lambda(A) = -27.9(-5.4)(+7.1 degrees), marking the first quantitative finding of significant misalignment in a binary system with an F-class primary. We did not find compelling evidence for misalignment in the remaining systems; however TIC 410314066 remains a strong candidate for follow-up, as our incomplete data set hints at possible misalignment in this case. Taken together, these results expand the current limited sample of binary systems with quantitative obliquity measurements, particularly for systems with cooler primaries. While most binaries appear aligned, the significant misalignment in TIC 28051929 demonstrates that substantial spin-orbit tilts can persist even in systems where tidal realignment would otherwise be expected to act.

ABSTRACT We report a joint analysis of TESS photometry and minerva-Australis spectroscopic observations for seven long-period eclipsing binary systems with F- and early-G-type dwarf primaries: TIC 37606218, TIC 73723286, TIC 172462064, TIC 220567625, TIC 270805930, TIC 308050066, and TIC 308991822. The companions are late-K to late-M dwarfs with orbital periods of $\sim$7–24 d, with all but one system exhibiting significant eccentricity. The combination of low-mass companions and relatively long orbital periods place these binaries in a regime where tidal interactions are comparatively weak, making them valuable benchmarks for testing low-mass stellar models with minimal tidal contamination. For the systems analysed here, together with those from our previous studies, we find that the radii and effective temperatures of the low-mass companions are broadly consistent with MIST isochrone predictions, with only a modest mean radius anomaly of $\sim 1~{{\ \rm per\ cent}}$ and no statistically significant temperature anomaly. We furthermore find no compelling evidence for correlations between either anomaly and orbital period or metallicity, suggesting that the processes commonly invoked to explain the radius–temperature anomaly are either not the dominant drivers, or operate much less efficiently in the longer-period regime.

We present resolutions as to the nature of six speculative candidate companions proposed in the final data release of the Pan-Pacific Planet Search, a 6-yr radial-velocity survey of 164 southern evolved stars using the now-decommissioned University College London Echelle Spectrograph (UCLES) on the 3.9m Anglo-Australian Telescope (AAT). New radial-velocity observations, TESS asteroseismology, and Hipparcos-Gaia astrometry are incorporated to refine the companion and host-star parameters. We confirm that HD 126105b is a giant planet (P = 524.0 +/- 2.9 d, m sin i = 1.67(-0.17)(+0.19) M-J), and that HD 205577B is a massive, eccentric brown dwarf ( P similar to 11.2 yr, m = 77(-9)(+11) M-J, e = 0.68). HD 115066B and HD 121156B are low-mass stellar companions, while HD 114899 and HD 159743 are shown to be unadorned by any detectable companions whatsoever. This demonstrates the utility of astrometric information to help overcome the temporal limitations of incomplete radial-velocity data sets and elucidate the true nature of suspected companion bodies.

Measuring the properties of planets younger than about 50 Myr helps to test different planetary formation and evolution models. NASA’s Transiting Exoplanet Survey Satellite (TESS) has observed nearly the entire sky, including a wide range of star-forming regions and young stellar clusters, expanding our census of the newborn planet population. In this work, we present the discovery of the TIC 88785435 planetary system located in the Upper Centaurus Lupus (UCL) region of the Scorpius Centaurus OB association (Sco-Cen) and a preliminary survey of the planet population within Sco-Cen. TIC 88785435 is a pre-main-sequence, K7V dwarf ( M _⋆ = 0.72 M _⊙ , R _⋆ = 0.91 R _⊙ , T _eff = 3998 K, V = 11.7 mag) located within the bounds of UCL. We investigate the distribution of rotation periods measured from the TESS long-cadence data and the H α and Li abundances from the spectra of TIC 88785435. TESS long-cadence data reveal that TIC 88785435 hosts a transiting super-Neptune ( R _b = 5.03 R _⊕ , P = 10.51 days), TIC 88785435b. Ground-based follow-up validates the planetary nature of TIC 88785435b. Using the TESS data, we perform a preliminary survey to investigate how TIC 88785435b compares to the population of newly born planets located within Sco-Cen.

Giant planets are expected to predominantly form beyond the water-ice line and occasionally undergo inward migration. Unlike hot Jupiters, which can result from high-eccentricity tidal migration, warm Jupiters between 0.1 and 1 au (≈10–365 days) are in many ways more challenging to explain because they reside outside the tidal influence of their host stars. Warm Jupiters should therefore preserve traces of their origins as their eccentricities are directly related to their past interactions. We analyze the eccentricities of 200 warm Jupiters orbiting 194 Sunlike host stars (with FGKM spectral types) using 18,587 radial velocity (RV) measurements across 40 high-resolution spectrographs. RVs are compiled from the literature and are supplemented with 540 new observations from MINERVA-Australis at Mount Kent Observatory and the Habitable-zone Planet Finder spectrograph at McDonald Observatory’s Hobby-Eberly Telescope, which are timed to improve eccentricity constraints by sampling orbits near periastron passage. The overarching goal of this program is to establish the relative importance of giant planet migration channels through the largest homogeneous analysis of warm Jupiter orbital properties to date. In particular, we evaluate and compare the impact of different system architectures and host star characteristics on the population-level eccentricity distributions of warm Jupiters. Here, we present the target sample, observations, orbit-fitting procedure, and parameter summary statistics of our survey. All orbit fit solutions, parameter posterior chains, and merged RV tables for each system are made publicly available.

Atmospheric mass loss is thought to induce the bimodality in the small planet population as we observe it today. Observationally, active mass loss can be traced by excess absorption in spectral lines of lighter species, such as the hydrogen Ly-alpha line and the metastable helium triplet. We search for helium escape from the young (120Myr old) sub-Neptune HIP94235b. We obtained two transit observations of HIP94235b using the CRyogenic InfraRed Echelle Spectrograph (CRIRES+) on the Very Large Telescope (VLT). We find no evidence for escaping helium across both visits, allowing us to place a mass loss rate upper limit of 10^11 g/s, based on 1D Parker wind models. Additionally, we search for molecular spectral features in the planet's transmission spectrum, and cross-correlate our observations with high-resolution template spectra for H2O, the dominating molecule in the Y-band. We detect no significant absorption. We demonstrate that some atmosphere models at 10x solar metallicity would have been retrievable if present. Through the null detection of neutral hydrogen and helium escape, we conclude the atmosphere of HIP94235b likely lacks a large hydrogen-helium envelope. This is consistent with the expectation of small planet photoevaporation models, which suggest most planets lose their primordial hydrogen-helium envelopes within 100Myr of evolution.

We present time-series radial velocities of the G8 subgiant star beta Aql obtained in 2022 and 2023 using SONG-Tenerife and, for the first time, SONG-Australia. We also analyse a sector of TESS photometry that overlapped with the 2022 SONG data. The resulting power spectrum clearly shows solar-like oscillations centred at 430 muHz. The TESS light curve shows the oscillations at lower signal-to-noise, reflecting the fact that photometric measurements are much more affected by the granulation background than are radial velocities. The simultaneous observations in velocity and photometry represent the best such measurements for any star apart from the Sun. They allowed us to measure the ratio between the bolometric photometric amplitude and the velocity amplitude to be 26.6 +/- 3.1 ppm/(m/s). We measured this ratio for the Sun from published SOHO data to be 19.5 +/- 0.7 ppm/(m/s) and, after accounting for the difference in effective temperatures of and the Sun, these values align with expectations. In both the Sun and beta Aql, the photometry-to-velocity ratio appears to be a function of frequency. We also measured the phase shift of the oscillations in beta Aql between SONG and TESS to be -113 +/- 7 deg, which agrees with the value for the Sun and also with a 3-D simulation of a star with similar properties to beta Aql. Importantly for exoplanet searches, we argue that simultaneous photometry can be used to predict the contribution of oscillations to radial velocities. We measured frequencies for 22 oscillation modes in beta Aql and carried out asteroseismic modelling, yielding an excellent fit to the frequencies. We derived accurate values for the mass and age, and were able to place quite strong constraints on the mixing-length parameter. Finally, we show that the oscillation properties of beta Aql are very similar to stars in the open cluster M67.

We present a joint analysis of TESS photometry and radial velocity measurements obtained from the Minerva-Australis facility for two short-period eclipsing binaries, TIC 48227288 and TIC 339607421. TIC 339607421 hosts an M-dwarf companion ( M-B = 0 . 294 +/- 0 . 013 M-circle dot, R-B = 0 . 291 +/- 0 . 006 R (circle dot)) orbiting an F6V star ( M-A = 1 . 09 +/- 0.04M(circle dot), R-A = 1 . 21+ 0 . 03-0.02 R-circle dot), while TIC 48227288 contains a late K class companion ( M-B = 0 . 635 +/- 0 . 037 M-circle dot, R-B = 0 . 605 +/- 0 . 011 R-circle dot) orbiting an F3V star ( M-A = 1 . 36(-0.08)(+ 0 . 06) M-circle dot, R-A = 1 . 61 +/- 0 . 03 R-circle dot). Both companions follow short period, near-circular orbits (P-B = 2.4-3.0 d, e approximate to 0 . 001). Sky-projected obliquities for each system were derived using a classical analysis of the RV perturbation and the Reloaded Rossiter-McLaughlin (RRM) technique. The classical method indicates minor spin-orbit misalignment for both systems ( lambda(A) = (+5.4)(-5.9) degrees and-17.8(+1.9)-(-2.0) degrees for TIC 339607421 and TIC 48227288, respectively). The RRM analysis yields smaller obliquities (lambda(A) = -8.2 +/- 0.2 degrees and-9.5 +/- 0.2 degrees respectively), but confirms the minor misalignment inferred from the classical analysis. The findings of misaligned, circular orbits are notable even though the misalignments are not large, and suggest potential gaps in current models of binary formation and orbital evolution. As such, further investigation of these and similar systems appears warranted.

We present the eccentricity distribution of warm sub-Saturns (4-8 Re, 8-200 day periods) as derived from an analysis of transit light curves from NASA's Transiting Exoplanet Survey Satellite (TESS) mission. We use the "photoeccentric" effect to constrain the eccentricities of 76 planets, comprising 60 and 16 from single- and multi-transiting systems, respectively. We employ Hierarchical Bayesian Modelling to infer the eccentricity distribution of the population, testing both a Beta and Mixture Beta distribution. We identify a few highly eccentric (e 0.7-0.8) warm sub-Saturns with eccentricities that appear too high to be explained by disk migration or planet-planet scattering alone, suggesting high-eccentricity migration may play a role in their formation. The majority of the population have a mean eccentricity of e = 0.103+0.047-0.045, consistent with both planet-disk and planet-planet interactions. Notably, we find that the highly eccentric sub-Saturns occur in single-transiting systems. This study presents the first evidence at the population level that the eccentricities of sub-Saturns may be sculpted by dynamical processes.

The recent discoveries of Neptune-sized ultra-short-period planets (USPs) challenge existing planet formation theories. It is unclear whether these residents of the Hot Neptune Desert have similar origins to smaller, rocky USPs, or if this discrete population is evidence of a different formation pathway altogether. We report the discovery of TOI-3261b, an ultrahot Neptune with an orbital period P = 0.88 day. The host star is a V = 13.2 mag, slightly supersolar metallicity ([Fe/H] similar or equal to 0.15), inactive K1.5 main-sequence star at d = 300 pc. Using data from the Transiting Exoplanet Survey Satellite and the Las Cumbres Observatory Global Telescope, we find that TOI-3261b has a radius of 3.82-0.35+0.42 R circle plus. Moreover, radial velocities from ESPRESSO and HARPS reveal a mass of 30.3-2.4+2.2 M circle plus, more than twice the median mass of Neptune-sized planets on longer orbits. We investigate multiple mechanisms of mass loss that can reproduce the current-day properties of TOI-3261b, simulating the evolution of the planet via tidal stripping and photoevaporation. Thermal evolution models suggest that TOI-3261b should retain an envelope potentially enriched with volatiles constituting similar to 5% of its total mass. This is the second highest envelope mass fraction among ultrahot Neptunes discovered to date, making TOI-3261b an ideal candidate for atmospheric follow-up observations.

HIP94235 b, a 120 Myr old sub-Neptune, provides us the unique opportunity to study mass loss at a pivotal stage of the system’s evolution: the end of a 100 Myr old phase of intense XUV irradiation. We present two observations of HIP94235 b using the Hubble Space Telescope’s Space Telescope Imaging Spectrograph in the Ly α wavelength region. We do not observe discernible differences across either the blue and red wings of the Ly α line profile in and out of transit, and report no significant detection of outflowing neutral hydrogen around the planet. We constrain the rate of neutral hydrogen escaping HIP94235 b to an upper limit of 10 13 gs −1 , which remains consistent with energy-limited model predictions of 10 11 gs −1 . The Ly α nondetection is likely due to the extremely short photoionization timescale of the neutral hydrogen escaping the planet’s atmosphere. This timescale, approximately 15 minutes, is significantly shorter than that of any other planets with STIS observations. Through energy-limited mass loss models, we anticipate that HIP94235 b will transition into a super-Earth within a timescale of 1 Gyr.

We present a catalogue of binary companions to delta Scuti stars, detected through phase modulations of their pulsations in Transiting Exoplanet Survey Satellite (TESS) data. Pulsation timing has provided orbits for hundreds of pulsating stars in binaries from space-based photometry. We have applied this technique to delta Sct stars observed in the first four years of TESS mission photometry. We searched the 2-min cadence light curves of 1161 short-period instability strip pulsators for variations in pulsation phase caused by the dynamical influence of an unseen companion. We discovered 53 new binaries and we present orbital parameters and mass functions for the 24 systems with solvable orbits. For the brightest star in our sample alpha Pictoris, we perform a joint fit of the pulsation timing and Hipparcos astrometry. We present the first orbit for the alpha Pictoris system, obtaining an orbital period of 1316 +/- 2 d and a mass for alpha Pic B of 1.05 +/- 0.05 M-circle dot. We revisit pulsation timing binaries from Kepler with Gaia kinematics, finding four systems that are members of the Galactic thick disc or halo. This suggests that they have been rejuvenated by mass transfer, and their companions are now white dwarfs. Further follow-up of these systems may yield valuable constraints of the Galactic blue straggler population.

We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a bright ($V=12.6$ mag, $K=7.8$ mag) metal-poor M4V star only $12.162\pm0.005$ pc away from the Solar System with one of the lowest stellar activity levels known for an M-dwarf. A planet candidate was detected by TESS based on only 3 transits in sectors 42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory, as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of $12.76144\pm0.00006$ days and a radius of $1.0\pm{0.1}$ R$_\oplus$, resulting in an equilibrium temperature of $\sim$315K. Gliese 12 b has excellent future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the Galaxy.

Context. Hot and warm Jupiters might have undergone the same formation and evolution path, but the two populations exhibit different distributions of orbital parameters. This challenges our understanding of their actual origin. Aims. We report the results of our warm Jupiters survey, which was carried out with the CHIRON spectrograph within the KESPRINT collaboration. We addressed the question of the population origin by studying two planets that might help to bridge the gap between the two populations. Methods. We confirm two planets and determine their mass. One is a hot Jupiter (with an orbital period shorter than 10 days), TOI-2420 b, and the other is a warm Jupiter, TOI-2485 b. We analyzed them using a wide variety of spectral and photometric data in order to characterize these planetary systems. Results. We found that TOI-2420 b has an orbital period of P-b=5.8 days, a mass of M-b=0.9 M-J, and a radius of R-b=1.3 R-J, with a planetary density of 0.477 g cm(-3). TOI-2485 b has an orbital period of P-b=11.2 days, a mass of M-b=2.4 M-J, and a radius of R-b=1.1 R-J with a density of 2.36 g cm(-3). Conclusions. With the current parameters, the migration history for TOI-2420 b and TOI-2485 b is unclear: Scenarios of a high-eccentricity migration cannot be ruled out, and the characteristics of TOI-2485 b even support this scenario.

We present the discovery of TOI-1994b, a low-mass brown dwarf transiting a hot subgiant star on a moderately eccentric orbit. TOI-1994 has an effective temperature of 7700-410+720 K, V magnitude of 10.51 mag and log(g) of 3.982-0.065+0.067 . The brown dwarf has a mass of 22.1-2.5+2.6 M J, a period of 4.034 days, an eccentricity of 0.341-0.059+0.054 , and a radius of 1.220-0.071+0.082 R J. TOI-1994b is more eccentric than other transiting brown dwarfs with similar masses and periods. The population of low-mass brown dwarfs may have properties similar to planetary systems if they were formed in the same way, but the short orbital period and high eccentricity of TOI-1994b may contrast this theory. An evolved host provides a valuable opportunity to understand the influence stellar evolution has on the substellar companion's fundamental properties. With precise age, mass, and radius, the global analysis and characterization of TOI-1994b augments the small number of transiting brown dwarfs and allows the testing of substellar evolution models.

We report the discovery and confirmation of the Transiting Exoplanet Survey Satellite (TESS) single-transit, warm and dense sub-Saturn, TIC 139270665 b. This planet is unusually dense for its size: with a bulk density of 2.13 g cm-3 (0.645R J , 0.463M J ), it is the densest warm sub-Saturn of the TESS family. It orbits a metal-rich G2 star. We also found evidence of a second planet, TIC 139270665 c, with a longer period of 1010-220+780 days and minimum mass MPsini of 4.89-0.37+0.66 M J . First clues of TIC 139270665 b's existence were found by citizen scientists inspecting TESS photometric data from sector 47 in 2022 January. Radial velocity measurements from the Automated Planet Finder combined with TESS photometry and spectral energy distributions via EXOFASTv2 system modeling suggested a 23.624-0.031+0.030 day orbital period for TIC 139270665 b and also showed evidence for the second planet. Based on this estimated period, we mobilized the Unistellar citizen science network for photometric follow-up, capitalizing on their global distribution to capture a second transit of TIC 139270665 b. This citizen science effort also served as a test bed for an education initiative that integrates young students into modern astrophysics data collection. The Unistellar photometry did not definitively detect a second transit, but did enable us to further constrain the planet's period. As a transiting, warm, and dense sub-Saturn, TIC 139270665 b represents an interesting laboratory for further study to enhance our models of planetary formation and evolution.

We report the discovery and validation of HD 21520 b, a transiting planet found with TESS and orbiting a bright G dwarf (V=9.2, $T_{eff} = 5871 \pm 62$ K, $R_{\star} = 1.04\pm 0.02\, R_{\odot}$). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 days. However, our analysis supports instead a single-planet system with an orbital period of $25.1292\pm0.0001$ days and radius of $2.70 \pm 0.09\, R_{\oplus}$. Three full transits in sectors 4, 30 and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and MINERVA-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of $7.9^{+3.2}_{-3.0}\, M_{\oplus}$, with a 3-$\sigma$ upper limit of 17.7 $M_{\oplus}$. Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520 b is a promising candidate for further mass measurements and for atmospheric characterization.

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.

ABSTRACT 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 ∼17.5 h observation for the transits of both planets using ESA CHEOPS. We place ≤4.5 min and ≤2.5 min limits on the absence of transit timing variations over the 3 yr 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 Rp = $1.829_{-0.067}^{+0.096}$ R⊕, 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 Rp = $2.40_{-0.08}^{+0.10}$ R⊕ 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.