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As an inflated hot Jupiter orbiting an early-type primary star in the evolved binary HD 202772 system, HD 202772 A b’s presence invites a study of how such a planet forms and evolves. As a prelude to potential atmospheric characterization with the latest generation of observatories, we present a reduction and analysis of eclipse light-curve observations of HD 202772 A b acquired with the Spitzer Space Telescope using the 3.6 and 4.5 μ m channels. We find eclipse depths of 680 ± 68 and ${1081}_{-53}^{+54}$ ppm, respectively, corresponding to dayside effective temperatures of ${2130}_{-91}^{+102}$ and ${2611}_{-49}^{+46}$ K. The corresponding Bond albedos are consistent with the distribution of albedos for hot Jupiters observed with both Spitzer and Transiting Exoplanet Survey Satellite. The heat redistribution efficiencies consistent with the Bond albedo range predicted by one-dimensional atmospheric models in radiative-convective equilibrium are 0.71 ± 0.10 and ${0.03}_{-0.02}^{+0.03}$ , respectively, indicating a weak day–night contrast for the former and a strong contrast for the latter. Given this, and the unique environment in which this planet resides, we recommend follow-up observations with JWST to more precisely constrain its atmospheric composition and structure, as well as its host stellar environment, to elucidate if and how the atmospheres of these close-in giants evolve with host stars in binaries past the main sequence.

We present optical spectroscopy of 710 solar neighborhood stars collected over 20 years to catalog chromospheric activity and search for stellar activity cycles. The California Legacy Survey stars are amenable to exoplanet detection using precise radial velocities, and we present their Ca ii H and K time series as a proxy for stellar and chromospheric activity. Using the High Resolution Echelle Spectrometer at Keck Observatory, we measured stellar flux in the cores of the Ca ii H and K lines to determine S -values on the Mount Wilson scale and the $\mathrm{log}({R}_{\mathrm{HK}}^{{\prime} })$ metric, which is comparable across a wide range of spectral types. From the 710 stars, with 52,372 observations, 285 stars were sufficiently sampled to search for stellar activity cycles with periods of 2–25 yr, and 138 stars showed stellar cycles of varying length and amplitude. S -values can be used to mitigate stellar activity in the detection and characterization of exoplanets. We used them to probe stellar dynamos and to place the Sun's magnetic activity into context among solar neighborhood stars. Using precise stellar parameters and time-averaged activity measurements, we found tightly constrained cycle periods as a function of stellar temperature between $\mathrm{log}({R}_{\mathrm{HK}}^{{\prime} })$ of −4.7 and −4.9, a range of activity in which nearly every star has a periodic cycle. These observations present the largest sample of spectroscopically determined stellar activity cycles to date.

Exoplanet discoveries have revealed a dramatic diversity of planet sizes across a vast array of orbital architectures. Sub-Neptunes are of particular interest; due to their absence in our own solar system, we rely on demographics of exoplanets to better understand their bulk composition and formation scenarios. Here, we present the discovery and characterization of TOI-1437 b, a sub-Neptune with a 18.84 day orbit around a near-solar analog ( M _⋆ = 1.10 ± 0.10 M _☉ , R _⋆ =1.17 ± 0.12 R _☉ ). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite (TESS) mission and radial velocity (RV) follow-up observations were carried out as a part of the TESS-Keck Survey using both the HIRES instrument at Keck Observatory and the Levy Spectrograph on the Automated Planet Finder telescope. A combined analysis of these data reveal a planet radius of R _p = 2.24 ± 0.23 R _⊕ and a mass measurement of M _p = 9.6 ± 3.9 M _⊕ ). TOI-1437 b is one of few (∼50) known transiting sub-Neptunes orbiting a solar-mass star that has a RV mass measurement. As the formation pathway of these worlds remains an unanswered question, the precise mass characterization of TOI-1437 b may provide further insight into this class of planet.

The degree of alignment between a star’s spin axis and the orbital plane of its planets (the stellar obliquity) is related to interesting and poorly understood processes that occur during planet formation and evolution. Hot Jupiters orbiting hot stars (≳6250 K) display a wide range of obliquities, while similar planets orbiting cool stars are preferentially aligned. Tidal dissipation is expected to be more rapid in stars with thick convective envelopes, potentially explaining this trend. Evolved stars provide an opportunity to test the damping hypothesis, particularly stars that were hot on the main sequence and have since cooled and developed deep convective envelopes. We present the first systematic study of the obliquities of hot Jupiters orbiting subgiants that recently developed convective envelopes using Rossiter–McLaughlin observations. Our sample includes two newly discovered systems in the Giants Transiting Giants survey (TOI-6029 b, TOI-4379 b). We find that the orbits of hot Jupiters orbiting subgiants that have cooled below ∼6250 K are aligned or nearly aligned with the spin axis of their host stars, indicating rapid tidal realignment after the emergence of a stellar convective envelope. We place an upper limit for the timescale of realignment for hot Jupiters orbiting subgiants at ∼500 Myr. Comparison with a simplified tidal evolution model shows that obliquity damping needs to be ∼4 orders of magnitude more efficient than orbital period decay to damp the obliquity without destroying the planet, which is consistent with recent predictions for tidal dissipation from inertial waves excited by hot Jupiters on misaligned orbits.

NASA’s Transiting Exoplanet Survey Satellite (TESS) has identified over 7000 candidate exoplanets via the transit method, with gas giants among the most readily detected due to their large radii. Even so, long intervals between TESS observations for much of the sky lead to candidates for which only a single transit is detected in one TESS sector, leaving those candidate exoplanets with unconstrained orbital periods. Here, we confirm the planetary nature of TIC 393818343 b, originally identified via a single TESS transit, using radial velocity data and ground-based photometric observations from citizen scientists with the Unistellar Network and Exoplanet Watch. We determine a period of P = 16.24921 ${}_{-0.00011}^{+0.00010}$ days, a mass M _P = 4.34 ± 0.15 M _J , and semimajor axis a = 0.1291 ${}_{-0.0022}^{+0.0021}$ au, placing TIC 393818343 b in the “warm Jupiter” population of exoplanets. With an eccentricity e = 0.6058 ± 0.0023, TIC 393818343 b is the most eccentric warm Jupiter to be discovered by TESS orbiting less than 0.15 au from its host star and therefore an excellent candidate for follow-up, as it may inform our future understanding of how hot and warm Jupiter populations are linked.

We confirm a massive sub-Neptune-sized planet on a P = 22.8 days orbit around the star TOI-1824 ( T _eff = 5200 K, V = 9.7 mag). TESS first identified TOI-1824 b (formerly TOI-1824.01) as an object of interest in 2020 April after two transits in Sector 22 were matched with a single transit in Sector 21. TOI-1824 was subsequently targeted for ground-based Doppler monitoring with Keck-HIRES and APF-Levy. Using a joint model of the TESS photometry, radial velocities, and Ca ii H and K emission measurements as an activity indicator, we find that TOI-1824 b is an unusually dense sub-Neptune. The planet has a radius R _p = 2.63 ± 0.15 R _⊕ and mass M _p = 18.5 ± 3.2 M _⊕ , implying a bulk density of 5.6 ± 1.4 g cm ^−3 . TOI-1824 b's mass and radius situate it near a small group of “superdense sub-Neptunes” ( R _p ≲ 3 R _⊕ and M _p ≳ 20 M _⊕ ). While the formation mechanism of superdense sub-Neptunes is a mystery, one possible explanation is the constructive collision of primordial icy cores; such giant impacts would drive atmospheric escape and could help explain these planets' apparent lack of massive envelopes. We discuss TOI-1824 b in the context of these overdense planets, whose unique location in the exoplanet mass–radius plane make them a potentially valuable tracer of planet formation.

The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from Kepler. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data that has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached ≥5 σ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three-year survey. We took the opportunity to assess the performance of our survey and found that we achieved many of our goals, including measuring the mass of 38 small (

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 (0.645 R _J , 0.463 M _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 ${M}_{P}\sin i$ 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.

Multiplanet systems exhibit a diversity of architectures that diverge from the solar system and contribute to the topic of exoplanet demographics. Radial velocity (RV) surveys form a crucial component of exoplanet surveys, as their long observational baselines allow for searches for more distant planetary orbits. This work provides a significantly revised architecture for the multiplanet system HD 134606 using both HARPS and UCLES RVs. We confirm the presence of previously reported planets b, c, and d with periods of ${12.0897}_{-0.0018}^{+0.0019}$ , ${58.947}_{-0.054}^{+0.056}$ , and ${958.7}_{-5.9}^{+6.3}$ days and masses of ${9.14}_{-0.63}^{+0.65}$ , 11.0 ± 1, and 44.5 ± 2.9 Earth masses, respectively, with the planet d orbit significantly revised to over double that originally reported. We report two newly detected super-Earths, e and f, with periods of ${4.31943}_{-0.00068}^{+0.00075}$ and ${26.9}_{-0.017}^{+0.019}$ days and masses of ${2.31}_{-0.35}^{+0.36}$ and ${5.52}_{-0.73}^{+0.74}$ Earth masses, respectively. In addition, we identify a linear trend in the RV time series, and the cause of this acceleration is deemed to be a newly detected massive companion with a very long orbital period. HD 134606 now displays four low-mass planets in a compact region near the star, one gas giant further out in the habitable zone, an additional companion in the outer regime, and a low-mass M dwarf stellar companion at large separation, making it an intriguing target for system formation/evolution studies. The location of planet d in the habitable zone proves to be an exciting candidate for future space-based direct imaging missions, whereas continued RV observations of this system are recommended for understanding the nature of the massive, long-period companion.

The extreme environments of ultra-short-period planets (USPs) make excellent laboratories to study how exoplanets obtain, lose, retain, and/or regain gaseous atmospheres. We present the confirmation and characterization of the USP TOI-1347 b, a 1.8 ± 0.1 R _⊕ planet on a 0.85 day orbit that was detected with photometry from the TESS mission. We measured radial velocities of the TOI-1347 system using Keck/HIRES and HARPS-N and found the USP to be unusually massive at 11.1 ± 1.2 M _⊕ . The measured mass and radius of TOI-1347 b imply an Earth-like bulk composition. A thin H/He envelope (>0.01% by mass) can be ruled out at high confidence. The system is between 1 and 1.8 Gyr old; therefore, intensive photoevaporation should have concluded. We detected a tentative phase-curve variation (3 σ ) and a secondary eclipse (2 σ ) in TESS photometry, which, if confirmed, could indicate the presence of a high-mean-molecular-weight atmosphere. We recommend additional optical and infrared observations to confirm the presence of an atmosphere and investigate its composition.

The Transiting Exoplanet Survey Satellite (TESS) continues to increase dramatically the number of known transiting exoplanets, and is optimal for monitoring bright stars amenable to radial velocity (RV) and atmospheric follow-up observations. TOI-1386 is a solar-type (G5V) star that was detected via TESS photometry to exhibit transit signatures in three sectors with a period of 25.84 days. We conducted follow-up RV observations using Keck/High Resolution Echelle Spectrometer (HIRES) as part of the TESS–Keck Survey, collecting 64 RV measurements of TOI-1386 with the HIRES spectrograph over 2.5 yr. Our combined fit of the TOI-1386 photometry and RV data confirm the planetary nature of the detected TESS signal, and provide a mass and radius for planet b of 0.148 ± 0.019 M _J and 0.540 ± 0.017 R _J , respectively, marking TOI-1386 b as a warm sub-Saturn planet. Our RV data further reveal an additional outer companion, TOI-1386 c, with an estimated orbital period of 227.6 days and a minimum mass of 0.309 ± 0.038 M _J . The dynamical modeling of the system shows that the measured system architecture is long-term stable, although there may be substantial eccentricity oscillations of the inner planet due to the dynamical influence of the outer planet.

Discovering and characterizing exoplanets at the outer edge of the transit method’s sensitivity has proven challenging owing to geometric biases and the practical difficulties associated with acquiring long observational baselines. Nonetheless, a sample of giant exoplanets on orbits longer than 100 days has been identified by transit hunting missions. We present long-term Doppler spectroscopy for 11 such systems with observation baselines spanning a few years to a decade. We model these radial velocity observations jointly with transit photometry to provide initial characterizations of these objects and the systems in which they exist. Specifically, we make new precise mass measurements for four long-period giant exoplanets (Kepler-111 c, Kepler-553 c, Kepler-849 b, and PH-2 b), we place new upper limits on mass for four others (Kepler-421 b, KOI-1431.01, Kepler-1513 b, and Kepler-952 b), and we show that several confirmed planets are in fact not planetary at all. We present these findings to complement similar efforts focused on closer-in short-period giant planets, and with the hope of inspiring future dedicated studies of cool giant exoplanets.

We present a radial velocity (RV) analysis of TOI-1136, a bright Transiting Exoplanet Survey Satellite (TESS) system with six confirmed transiting planets, and a seventh single-transiting planet candidate. All planets in the system are amenable to transmission spectroscopy, making TOI-1136 one of the best targets for intra-system comparison of exoplanet atmospheres. TOI-1136 is young (∼700 Myr), and the system exhibits transit timing variations (TTVs). The youth of the system contributes to high stellar variability on the order of 50 m s ^−1 , much larger than the likely RV amplitude of any of the transiting exoplanets. Utilizing 359 High Resolution Echelle Spectrometer and Automated Planet Finder RVs collected as part of the TESS-Keck Survey, and 51 High-Accuracy Radial velocity Planetary Searcher North RVs, we experiment with a joint TTV-RV fit. With seven possible transiting planets, TTVs, more than 400 RVs, and a stellar activity model, we posit that we may be presenting the most complex mass recovery of an exoplanet system in the literature to date. By combining TTVs and RVs, we minimized Gaussian process overfitting and retrieved new masses for this system: ( m _b−g = ${3.50}_{-0.7}^{+0.8}$ , ${6.32}_{-1.3}^{+1.1}$ , ${8.35}_{-1.6}^{+1.8}$ , ${6.07}_{-1.01}^{+1.09}$ , ${9.7}_{-3.7}^{+3.9}$ , ${5.6}_{-3.2}^{+4.1}$ M _⊕ ). We are unable to significantly detect the mass of the seventh planet candidate in the RVs, but we are able to loosely constrain a possible orbital period near 80 days. Future TESS observations might confirm the existence of a seventh planet in the system, better constrain the masses and orbital properties of the known exoplanets, and generally shine light on this scientifically interesting system.

Warm Jupiters are close-in giant planets with relatively large planet–star separations (i.e., 10 < a / R _⋆ < 100). Given their weak tidal interactions with their host stars, measurements of stellar obliquity may be used to probe the initial obliquity distribution and dynamical history for close-in gas giants. Using spectroscopic observations, we confirm the planetary nature of TOI-1859b and determine the stellar obliquity of TOI-1859 to be λ = 38.9 ${}_{-2.7}^{+2.8}$ ° relative to its planetary companion using the Rossiter–McLaughlin effect. TOI-1859b is a 64 day warm Jupiter orbiting around a late F dwarf and has an orbital eccentricity of 0.57 ${}_{-0.16}^{+0.12}$ inferred purely from transit light curves. The eccentric and misaligned orbit of TOI-1859b is likely an outcome of dynamical interactions, such as planet–planet scattering and planet–disk resonance crossing.

Large-scale exoplanet surveys like the Transiting Exoplanet Survey Satellite (TESS) mission are powerful tools for discovering large numbers of exoplanet candidates. Single-transit events are commonplace within the resulting candidate list due to the unavoidable limitation of the observing baseline. These single-transit planets often remain unverified due to their unknown orbital periods and consequent difficulty in scheduling follow-up observations. In some cases, radial velocity (RV) follow up can constrain the period enough to enable a future targeted transit detection. We present the confirmation of one such planet: TOI-2010 b. Nearly three years of RV coverage determined the period to a level where a broad window search could be undertaken with the Near-Earth Object Surveillance Satellite, detecting an additional transit. An additional detection in a much later TESS sector solidified our final parameter estimation. We find TOI-2010 b to be a Jovian planet ( M _P = 1.29 M _Jup , R _P = 1.05 R _Jup ) on a mildly eccentric orbit ( e = 0.21) with a period of P = 141.83403 days. Assuming a simple model with no albedo and perfect heat redistribution, the equilibrium temperature ranges from about 360 to 450 K from apastron to periastron. Its wide orbit and bright host star ( V = 9.85) make TOI-2010 b a valuable test bed for future low-insolation atmospheric analysis.

The success of the Transiting Exoplanet Survey Satellite mission has led to the discovery of an abundance of Venus Zone terrestrial planets that orbit relatively bright host stars. Atmospheric observations of these planets play a crucial role in understanding the evolutionary history of terrestrial planets, past habitable states, and the divergence of Venus and Earth climates. The transmission spectrum of a Venus-like exoplanet can be difficult to distinguish from that of an Earthlike exoplanet however, which could severely limit what can be learned from studying exoVenuses. In this work we further investigate differences in transmission between hypothetical exoEarths and exoVenuses, both with varying amounts of atmospheric carbon dioxide (CO _2 ). The exoEarths and exoVenuses were modeled assuming they orbit TRAPPIST-1 on the runaway greenhouse boundary. We simulated James Webb Space Telescope Near-Infrared Spectrograph PRISM transit observations of both sets of planets between 0.6 and 5.2 μ m, and quantified the detectability of major absorption features in their transmission spectra. The exoEarth spectra include several large methane (CH _4 ) features that can be detected in as few as six transits. The CH _4 feature at 3.4 μ m is the optimal for feature for discerning an exoEarth from an exoVenus since it is easily detectable and does not overlap with CO _2 features. The sulfur dioxide (SO _2 ) feature at 4.0 μ m is the best indicator of an exoVenus, but it is detectable in atmospheres with reduced CO _2 abundance.

With JWST’s successful deployment and unexpectedly high fuel reserves, measuring the masses of sub-Neptunes transiting bright, nearby stars will soon become the bottleneck for characterizing the atmospheres of small exoplanets via transmission spectroscopy. Using a carefully curated target list and observations from more than 2 yr of APF-Levy and Keck-HIRES Doppler monitoring, the TESS-Keck Survey is working toward alleviating this pressure. Here we present mass measurements for 11 transiting planets in eight systems that are particularly suited to atmospheric follow-up with JWST. We also report the discovery and confirmation of a temperate super-Jovian-mass planet on a moderately eccentric orbit. The sample of eight host stars, which includes one subgiant, spans early-K to late-F spectral types ( T _eff = 5200–6200 K). We homogeneously derive planet parameters using a joint photometry and radial velocity modeling framework, discuss the planets’ possible bulk compositions, and comment on their prospects for atmospheric characterization.

Both direct and indirect methods of exoplanet detection rely upon detailed knowledge of the potential host stars. Such stellar characterization allows for accurate extraction of planetary properties, as well as contributing to our overall understanding of exoplanetary system architecture. In this analysis, we examine the photometry of 264 known exoplanet host stars (harboring 337 planetary companions) that were observed during the Transiting Exoplanet Survey Satellite (TESS) Prime Mission. We identify periodic signatures in the lightcurves of these stars and make possible connections to stellar pulsations and their rotation periods, and compare the stellar variability to the published planetary orbital periods. From these comparisons, we quantify the effects of stellar variability on exoplanet detection, confirming that exoplanets detection is biased toward lower variability stars, but larger exoplanets dominate the population of exoplanets around variable stars. Exoplanet detection methods represented among these systems are distinct between stellar spectral types across the main sequence, though notable outliers exist. In addition, biases present in both the sourced data from TESS and the host star selection process, which strongly influences the representation of both stellar and planetary characteristics in the final populations. We also determine whether the host stars photometric variability affects or mimics the behavior or properties of the system’s planets. These results are discussed in the context of how the behavior of the host star is responsible for how we observe exoplanet characteristics, most notably their radii and atmospheric properties, and how the activity may alter our measurements or impact the evolution of planetary properties.

We present the stellar and planetary properties for 85 TESS Objects of Interest (TOIs) hosting 108 planet candidates that compose the TESS-Keck Survey (TKS) sample. We combine photometry, high-resolution spectroscopy, and Gaia parallaxes to measure precise and accurate stellar properties. We then use these parameters as inputs to a light-curve processing pipeline to recover planetary signals and homogeneously fit their transit properties. Among these transit fits, we detect significant transit-timing variations among at least three multiplanet systems (TOI-1136, TOI-1246, TOI-1339) and at least one single-planet system (TOI-1279). We also reduce the uncertainties on planet-to-star radius ratios R _p / R _⋆ across our sample, from a median fractional uncertainty of 8.8% among the original TOI Catalog values to 3.0% among our updated results. With this improvement, we are able to recover the Radius Gap among small TKS planets and find that the topology of the Radius Gap among our sample is broadly consistent with that measured among Kepler planets. The stellar and planetary properties presented here will facilitate follow-up investigations of both individual TOIs and broader trends in planet properties, system dynamics, and the evolution of planetary systems.

We describe the discovery of a solar neighborhood ( d = 468 pc) binary system with a main-sequence sunlike star and a massive noninteracting black hole candidate. The spectral energy distribution of the visible star is described by a single stellar model. We derive stellar parameters from a high signal-to-noise Magellan/MIKE spectrum, classifying the star as a main-sequence star with T _eff = 5972 K, $\mathrm{log}g=4.54$ , and M = 0.91 M _⊙ . The spectrum shows no indication of a second luminous component. To determine the spectroscopic orbit of the binary, we measured the radial velocities of this system with the Automated Planet Finder, Magellan, and Keck over four months. We show that the velocity data are consistent with the Gaia astrometric orbit and provide independent evidence for a massive dark companion. From a combined fit of our spectroscopic data and the astrometry, we derive a companion mass of ${11.39}_{-1.31}^{+1.51}$ M _⊙ . We conclude that this binary system harbors a massive black hole on an eccentric ( e = 0.46 ± 0.02), 185.4 ± 0.1 day orbit. These conclusions are independent of El-Badry et al., who recently reported the discovery of the same system. A joint fit to all available data yields a comparable period solution but a lower companion mass of ${9.32}_{-0.21}^{+0.22}{M}_{\odot }$ . Radial velocity fits to all available data produce a unimodal solution for the period that is not possible with either data set alone. The combination of both data sets yields the most accurate orbit currently available.

From the thousands of known exoplanets, those that transit bright host stars provide the greatest accessibility toward detailed system characterization. The first known such planets were generally discovered using the radial-velocity technique, then later found to transit. HD 17156b is particularly notable among these initial discoveries because it diverged from the typical hot-Jupiter population, occupying a 21.2 day eccentric ( e = 0.68) orbit, offering preliminary insights into the evolution of planets in extreme orbits. Here we present new data for this system, including ground- and space-based photometry, radial velocities, and speckle imaging, that further constrain the system properties and stellar/planetary multiplicity. These data include photometry from the Transiting Exoplanet Survey Satellite that cover five transits of the known planet. We show that the system does not harbor any additional giant planets interior to 10 au. The lack of stellar companions and the age of the system indicate that the eccentricity of the known planet may have resulted from a previous planet–planet scattering event. We provide the results from dynamical simulations that suggest possible properties of an additional planet that culminated in ejection from the system, leaving a legacy of the observed high eccentricity for HD 17156b.

We report the discovery of TOI-4127 b, which is a transiting, Jupiter-sized exoplanet on a long-period ( $P={56.39879}_{-0.00010}^{+0.00010}$ days) and a high-eccentricity orbit around a late F-type dwarf star. This warm Jupiter was first detected and identified as a promising candidate from a search for single-transit signals in TESS Sector 20 data, and was later characterized as a planet following two subsequent transits (TESS Sectors 26 and 53) and follow-up ground-based RV observations with the NEID and SOPHIE spectrographs. We jointly fit the transit and RV data to constrain the physical ( ${R}_{p}={1.096}_{-0.032}^{+0.039}{R}_{{\rm{J}}}$ , ${M}_{p}={2.30}_{-0.11}^{+0.11}{M}_{{\rm{J}}}$ ) and orbital parameters of the exoplanet. Given its high orbital eccentricity ( $e={0.7471}_{-0.0086}^{+0.0078}$ ), TOI-4127 b is a compelling candidate for studies of warm Jupiter populations and of hot Jupiter formation pathways. We show that the present periastron separation of TOI-4127 b is too large for high-eccentricity tidal migration to circularize its orbit, and that TOI-4127 b is unlikely to be a hot Jupiter progenitor unless it is undergoing angular momentum exchange with an undetected outer companion. Although we find no evidence for an external companion, the available observational data are insufficient to rule out the presence of a perturber that can excite eccentricity oscillations and facilitate tidal migration.

We present the Distant Giants Survey, a three-year radial velocity campaign to measure P(DG∣CS), the conditional occurrence of distant giant planets (DG; M _p ∼ 0.3–13 M _J , P > 1 yr) in systems hosting a close-in small planet (CS; R _p < 10 R _⊕ ). For the past two years, we have monitored 47 Sun-like stars hosting small transiting planets detected by TESS. We present the selection criteria used to assemble our sample and report the discovery of two distant giant planets, TOI-1669 b and TOI-1694 c. For TOI-1669 b we find that $M\sin i=0.573\pm 0.074\,\,{M}_{{\rm{J}}}$ , P = 502 ± 16 days, and e < 0.27, while for TOI-1694 c, $M\sin i=1.05\pm 0.05\,\,{M}_{{\rm{J}}}$ , P = 389.2 ± 3.9 days, and e = 0.18 ± 0.05. We also confirmed the 3.8 days transiting planet TOI-1694 b by measuring a true mass of M = 26.1 ± 2.2 M _⊕ . At the end of the Distant Giants Survey, we will incorporate TOI-1669 b and TOI-1694 c into our calculation of P(DG∣CS), a crucial statistic for understanding the relationship between outer giants and small inner companions.

The search for habitable planets has revealed many planets that can vary greatly from an Earth analog environment. These include highly eccentric orbits, giant planets, different bulk densities, relatively active stars, and evolved stars. This work catalogs all planets found to reside in the habitable zone (HZ) and provides HZ boundaries, orbit characterization, and the potential for spectroscopic follow-up observations. Demographics of the HZ planets are compared with a full catalog of exoplanets. Extreme planets within the HZ are highlighted, and how their unique properties may affect their potential habitability is discussed. Kepler-296 f is the most eccentric ≤2 R _⊕ planet that spends 100% of its orbit in the HZ. HD 106270 b and HD 38529 c are the most massive planets (≤13 M _J ) that orbit within the HZ, and are ideal targets for determining the properties of potential hosts of HZ exomoons. These planets, along with the others highlighted, will serve as special edge cases to the Earth-based scenario, and observations of these targets will help test the resilience of habitability outside the standard model. The most promising observational HZ target that is known to transit is GJ 414 A b. Of the transiting, ≤2 R _⊕ HZ planets, LHS 1140 b, TRAPPIST-1 d, and K2-3 d are the most favorable. Of the nontransiting HZ planets, HD 102365 b and 55 Cnc f are the most promising, and the best nontransiting candidates that have ≤2 R _⊕ are GJ 667 C c, Wolf 1061 c, Ross 508 b, Teegarden’s Star b, and Proxima Cen b.

Understanding the physical characteristics of Venus, including its atmosphere, interior, and its evolutionary pathway with respect to Earth, remains a vital component for terrestrial planet evolution models and the emergence and/or decline of planetary habitability. A statistical strategy for evaluating the evolutionary pathways of terrestrial planets lies in the atmospheric characterization of exoplanets, where the sample size provides sufficient means for determining required runaway greenhouse conditions. Observations of potential exo-Venuses can help confirm hypotheses about Venus’s past, as well as the occurrence rate of Venus-like planets in other systems. Additionally, the data from future Venus missions, such as DAVINCI, EnVision, and VERITAS, will provide valuable information regarding Venus, and the study of exo-Venuses will be complimentary to these missions. To facilitate studies of exo-Venus candidates, we provide a catalog of all confirmed terrestrial planets in the Venus zone, including transiting and nontransiting cases, and quantify their potential for follow-up observations. We examine the demographics of the exo-Venus population with relation to stellar and planetary properties, such as the planetary radius gap. We highlight specific high-priority exo-Venus targets for follow-up observations, including TOI-2285 b, LTT 1445 A c, TOI-1266 c, LHS 1140 c, and L98–59 d. We also discuss follow-up observations that may yield further insight into the Venus/Earth divergence in atmospheric properties.

We validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, $P={6.3980661}_{-0.0000097}^{+0.0000095}$ days, $e={0.294}_{-0.062}^{+0.13}$ , $M={0.94}_{-0.23}^{+0.31}{M}_{\mathrm{Nep}}$ ) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, $P={18.8805}_{-0.0011}^{+0.0024}$ days, $M={1.32}_{-0.32}^{+0.29}{M}_{\mathrm{Nep}}$ ) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3 σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by

We propose to design and build an algorithm that will use a convolutional neural network (CNN) and observations from the Unistellar Network to reliably detect asteroid occultations. The Unistellar Network is made of more than 10,000 digital telescopes owned by citizen scientists, and is regularly used to record asteroid occultations. In order to process the increasing amount of observational produced by this network, we need a quick and reliable way to analyze occultations. In an effort to solve this problem, we trained a CNN with artificial images of stars with 20 different types of photometric signals. Inputs to the network consist of two stacks of snippet images of stars, one around the star that is supposed to be occulted and a reference star used for comparison. We need the reference star to distinguish between a true occultation and artifacts introduced by a poor atmospheric condition. Our Occultation Detection Neural Network can analyze three sequences of stars per second with 91% precision and 87% recall. The algorithm is sufficiently fast and robust so we can envision incorporating it on board the eVscopes to deliver real-time results. We conclude that citizen science represents an important opportunity for the future studies and discoveries in the occultations, and that application of artificial intelligence will permit us to to take better advantage of the ever-growing quantity of data to categorize asteroids.