Marcelo Tala Pinto

Context. Warm Jupiters are excellent case studies for investigating giant planet internal structures and formation theories. However, the sample of long-period transiting giants today is not yet large enough to attain a better understanding of this population. Aims. Starting from a single transit found in the Transiting Exoplanet Survey Satellite (TESS) data, we confirmed the planetary nature of the signal and measured its orbital parameters, mass, and radius. We set this system in the context of long-period giant transiting planets and analyzed its viability for sustaining atmospheric or dynamical follow-ups. Methods. We carried out a spectroscopic follow-up using FEROS and PLATOSpec to obtain precise radial velocities. We added a photometric follow-up with HATPI and Observatoire Moana to obtain a more precise estimate of the orbital period. We derived the orbital and physical parameters through a joint analysis of these data. Results. We report the discovery and characterization of TIC65910228 b, a transiting warm Jupiter with a mass of 4.52 ± 0.26 M _J and a radius of 1.070 ± 0.049 R _J , orbiting an evolved F-type star every 180.5241 ± 0.0009 days in an eccentric orbit ( e = 0.26 ± 0.04). Conclusions. This planet joins a currently underexplored population of long-period ( P > 100 days), massive ( M _p > 4 M _J ), transiting giant planets, figuring as one of the few exhibiting a mild eccentricity. This target is a fine example of the potential of single-transit events to populate this region of the parameter space.

Transiting warm Jupiters orbiting bright stars are scarcely known, but a substantial number of these planets have been uncovered by the TESS mission. In this work, we report the discovery and confirmation of a transiting warm Jupiter orbiting the bright ( V = 8.70) subgiant star HD 715 (TOI-6893). HD 715 b was originally identified from a single transit event in TESS Sector 70. We acquired two seasons of radial velocity follow-up using the PFS, TRES, and MINERVA-Australis spectrographs, which clearly detect the planetary orbit. At M _* = 1.60 ± 0.04 M _⊙ , HD 715 thus becomes one of the most massive stars known to host a transiting warm Jupiter. From a joint fit to the TESS transit and our RVs, we find that HD 715 b has a 56.4 0 − 0.23 + 0.19 day orbital period and measure a precise mass and radius of 0.635 ± 0.056 M _J and 1.07 ± 0.04 R _J , rendering it a relatively typical member of the warm Jupiter population. The moderate orbital eccentricity of 0.2 1 − 0.08 + 0.07 contrasts with the higher eccentricities of other similar warm Jupiters orbiting evolved stars, indicating a greater diversity in orbital eccentricities than previously known. The absence of additional transits in preceding TESS observations in Sectors 42 and 43 allows us to further refine the range of possible orbital periods to [56.01, 56.35] days. Though the ephemeris uncertainty remains substantial, future photometric observations may nonetheless allow for recovery of the transit of HD 715 b.

Long-period transiting planets are essential edge-cases for understanding exoplanet formation and evolution. Their detection is challenging due to the infrequent nature of their transits, making every observation of these objects very valuable. Our goal is to confirm and further characterise the long-period planetary candidate TOI-4409,b (initially identified by TESS) through additional observations using the Antarctica-based ASTEP telescope, supplemented with CHAT, OMES, LCOGT, and PEST light-curve data and radial-velocity (RV) measurements collected with the HARPS, FEROS, and PFS instruments. We jointly analysed the photometric data from eight TESS, four ASTEP, one CHAT, two OMES, four LCOGT, and one PEST light curve(s), and RV data from the HARPS, FEROS, and PFS instruments, covering observations from 2018 to 2024. TOI-4409,b is a bona fide puffy warm super-Neptune exoplanet with a planet radius of 7.44 ± 0.19,R_⊕, and a mass of 0.047 ± J ,(3σ upper limit <0.095,M_ J) orbiting a low-mass main-sequence star (effective temperature of 4928 ± 48, and a stellar radius of 0.720 ± 0.018, _⊙) with a period of 92.49179 ± 0.00010 days. The integration of various observational methods and consistent transit signals across multiple instruments confirms the planetary nature of TOI-4409,b. The combined transit, imaging, chromaticity, and RV evidence supports the confirmation of the planet. K R With a radius of 7.44 ± 0.19,R_⊕ and a low bulk density of 0.20 ± 0.07 -3 $, TOI-4409,b occupies a sparsely populated region of parameter space among warm, puffy super-Neptunes on long-period orbits. The detection of candidate transit timing variations with an ∼10-minute semi-amplitude hints at the presence of an additional body in the system. The favourable host-star brightness and extended transit duration ($∼7 hours) make TOI-4409,b a promising target for atmospheric characterisation with JWST and Ariel.

We present the first results from the POSEIDON survey, aimed at constraining the dynamical origins of transiting Neptunes through stellar obliquity measurements. We report Rossiter–McLaughlin observations of two Neptunes, TOI-181 b and TOI-883 b, obtained with high-resolution spectroscopy from Magellan/Planet Finder Spectrograph and WIYN/NEID. TOI-181 b is on a 4.5-day orbit with a sky-projected spin–orbit misalignment λ = 32 . ° 0 − 6. ° 5 + 6. ° 3 and a low eccentricity ( e < 0.12 with 2 σ confidence). TOI-883 b has a longer orbital period of 10 days with λ = 2 2 ° − 14 ° + 15 ° and eccentricity e = 0.16 ± 0.03. The significant misalignment of TOI-181 b and the significant eccentricity of TOI-883 b are suggestive of high-eccentricity migration for both systems. After adding these and other new measurements to the sample, we analyze the obliquity distribution of the host stars of transiting Neptunes. Earlier studies had suggested that the obliquity distribution is bimodal, with peaks corresponding to aligned orbits and polar orbits; the addition of more measurements has weakened the evidence for bimodality. The current sample appears to be consistent with a population of well-aligned systems and a smaller population with nearly random obliquities. This distribution resembles that observed for more massive planets, suggesting that transiting Jupiters and Neptunes originate from similar dynamical processes.

We present the analysis of five long-period TESS Objects of Interest (TOIs), , with orbital periods exceeding one month. Initially identified by the Transiting Exoplanet Survey Satellite (TESS), we extensively monitored these targets with the Antarctic Search for Transiting Exoplanets (ASTEP), supported by other facilities in the TESS Follow-up Observing Program (TFOP) network. all orbiting Sun-like stars These targets occupy a relatively underexplored region of the period-radius parameter space, offering valuable primordial probes for planetary formation and migration as warm planets better maintain their evolutionary fingerprints. To characterise these systems, we leveraged high-resolution speckle imaging to search for nearby stellar companions, and refine stellar parameters using both reconnaissance spectroscopy and spectral energy distribution (SED) fitting. We combined TESS photometry with high-precision ground-based observations from ASTEP, and when available, included additional photometry and radial velocity data. We applied statistical validation to assess the planetary nature of each candidate and used to jointly model the photometric and spectroscopic datasets. We validate the planetary nature of three TOIs, including the two warm Saturns TOI-4507,b (8.2, 104,d) and TOI-3457,b (10.0, 32.6,d), as well as the warm sub-Neptune TOI-707,b (2.4, eclipsing binaries, namely TOI-2404 and TOI-4404. 52.8,d). The remaining two candidates are most consistent with These results help populate the sparse regime of warm planets, which serve as key tracers of planetary evolution, and demonstrate ASTEP’s effectiveness as a ground-based follow-up instrument for long-period systems.

We present four newly validated transiting brown dwarfs identified through TESS photometry and confirmed with high-precision radial velocity measurements obtained from the FEROS and PLATOSpec spectrographs. Notably, three of these companions exhibit orbital periods exceeding 100 days, thereby expanding the sample of long-period transiting brown dwarfs from four to seven systems. The host stars of the long-period brown dwarfs show mild subsolar metallicity. These discoveries highlight the expansion of the metal-poor long-period distribution and help us better understand the brown dwarf desert. In our comparative analysis of eccentricity and metallicity demographics, we utilized catalogs of long-period giant planets, brown dwarfs, and low-mass stellar companions. After accounting for tidal influences, the eccentricity distribution aligns with that of low-mass stellar binaries, presenting a different profile than that observed within the giant planet population. Additionally, the metallicity of the host stars reveals a noteworthy trend: Short-period transiting brown dwarfs are predominantly associated with metal-rich stars, whereas long-period brown dwarfs are more often found around metal-poor stars, thus demonstrating statistical similarities to low-mass stellar hosts. This trend has been previously observed in studies of hot and cold Jupiters and points to a period-coded mixture of channels. A natural explanation is that most brown dwarfs originate from fragmentation at wider separations, with long-period systems retaining this stellar-like imprint, while only those embedded in massive, long-lived metal-rich protoplanetary disks are efficiently delivered and stabilized to short orbits.

We report the discovery and characterisation of three transiting warm Jupiters: TIC 147027702b, TIC 245076932b, and TIC 87422071b. These systems were initially identified as transiting candidates using light curves generated from the full-frame images of the TESS mission. We confirmed the planetary nature of these objects with ground-based spectroscopic follow-up observations using FEROS and the new PLATOSpec spectrograph attached to the ESO 1.52 m telescope at the La Silla Observatory, and with ground-based photometric observations of the Observatoire Moana, Las Cumbres Observatory Global Telescope and ASTEP. From a global fit to the photometry and radial velocities, we determine that the planet TIC 147027702b has a low-eccentricity orbit ( e = 0.13 ± 0.05) with a period of 44.4 days, a mass of 1.09 _−0.13 ^+0.07 M _J , and a radius of 0.98 ± 0.06 R _J . TIC 245076932b has a moderately low mass of 0.51 ± 0.05 M _J , a radius of 0.97 ± 0.05 R _J , and an eccentric orbit ( e = 0.43 ± 0.02) with a period of 21.6 days. TIC 87422071b has a mass of 1.29 ± 0.10 M _J , a radius of 0.97 ± 0.08 R _J , and a slightly eccentric orbit ( e = 0.12 ± 0.07) with a period of 11.3 days. These well-characterised warm Jupiters expand the currently limited sample of similar gas giants and provide valuable benchmarks for testing models of giant-planet formation, migration, and tidal evolution.

We report the discovery and characterization of TOI-6692 b, an eccentric ( e ∼ 0.54) Jupiter on a 130 day orbit. TOI-6692 b was first detected as a community TESS Object of Interest by the Visual Survey Group and the Planet Hunters group as a single-transit candidate via TESS observation. The period was subsequently confirmed via radial velocity monitoring from the Planet Finder Spectrograph on the 6.5 m Magellan telescope. Additional radial velocities were acquired with the CHIRON, FEROS, and CORALIE spectrographs. LCOGT ground-based photometric follow-up was conducted over 2 weeks to detect another transit and refine the period. Although we did not detect an ingress or egress of the 11.04 hr transit, we did detect a possible in-transit signal in the multinight data and provide an updated ephemeris for future monitoring. TOI-6692 b is one of the few planets with orbital periods longer than 100 days that have a secure mass, radius, and eccentricity detection. As with most giant planets at these orbital periods, the eccentricity of TOI-6692 b is lower than that expected of planets undergoing high-eccentricity tidal migration, but is more consistent with the expectations of planet–planet scattering outcomes. A long-term radial velocity trend was detected, and further monitoring is warranted to determine the outer companion period. TOI-6692 b is also one of the few TESS single transit targets to have its periods eventually confirmed via follow-up photometric campaigns timed to capture transits despite the relatively large ephemeris uncertainties. Such efforts highlight the capabilities of night-to-night stability on ground-based photometric facilities today.

TOI-1232 is a G dwarf star with a mass of 1.0 6 − 0.06 + 0.07 M ⊙ , a radius of 1.07 ± 0.05 R _⊙ , and a slightly higher metallicity than solar of Fe/H = 0.18 ± 0.05. The star hosts a transiting warm Jovian-mass planet, TOI-1232 b, with an orbital period of P b = 14.25 6 − 0.001 + 0.001 days, identified with data from multiple sectors of the TESS space telescope. The TESS light curve of TOI-1232 is complex, as it is contaminated by a background eclipsing binary with a period of 1.37 days. TOI-1232 b was firmly confirmed by ground-based transit follow-up campaigns from the Las Cumbres, Hazelwood, Brierfield, and ASTEP observatories. Additionally, the TESS transits of TOI-1232 b exhibit strong transit-timing variations (TTVs) with a superperiod of 235.5 ± 0.7 days and a semiamplitude of 27 minutes. Radial velocity (RV) follow-up with the FEROS spectrograph confirms the planetary nature of the transiting candidate, while a self-consistent N -body analysis of RVs and TTVs pinpoints the presence of a second outer Saturn-mass companion, TOI-1232 c with a period of P c = 30.35 6 − 0.012 + 0.010 days. The TOI-1232 warm-giant system is particularly important due to the evidence of two massive planets that reside near the 2:1 commensurability but are not locked in a mean-motion resonance. Thanks to TESS, we have revealed a handful of these rare systems. Hence, TOI-1232 is an important addition to understanding the formation and dynamical evolution of such compact, massive, warm giant planets.