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Conventionally, the observed isolation of hot Jupiters, marked by a paucity of nearby low-mass planetary companions, has been interpreted as evidence of high-eccentricity tidal migration for these close-in gas giants. This loneliness is in stark contrast with the compact configurations commonly observed for warm Jupiters, indicating a curious dichotomy in dynamical origins between these two classes of short-period giants. In this study, however, we adopt a unified quiescent framework for both giant populations wherein they emerge from the protoplanetary disk as the sole Jovian planet within a compact multi-super-Earth system. We use long-term numerical simulations to show that post-disk dynamical evolution will naturally result in an observed preferential isolation for hot Jupiters relative to warm Jupiters. Specifically, their companions achieve significantly larger period ratios and mutual inclinations, rendering them more difficult to detect - especially via the transit method. Additionally, we find that this paradigm is consistent with the enigmatic population of longer-period hot Jupiters hosting interior companions on coplanar orbits. Another prediction of this model, best te

Of the > 500 confirmed transiting hot jupiters and approximately 2000 additional candidates today, only ten are known to have nearby companion planets. The survival of nearby companions means that these hot jupiters cannot have migrated to their present location via dynamically disruptive high-eccentricity migration but instead have undergone disk migration or formed in situ. The occurrence rate for these nearby companions, therefore, constrains the relative efficiency of different hot jupiter formation pathways. Here, we perform a uniform box least-squares search for nearby transiting companions to hot jupiters in the first five years of TESS data. Accounting for observational completeness and detection efficiency, we arrive at an occurrence rate of $(7.6^{+5.5}_{-3.8})\%$, which is a lower limit on the fraction of hot jupiters that underwent disk migration or in situ formation. Comparing this rate with that derived from transit-timing variation searches suggests that hot jupiters are likely mostly aligned with their nearby companions, but their apparently higher incidence of grazing transits may point to a slight preferential misalignment. We also synthesize evidence that hot

Warm giant planets with orbital periods of tens of days exhibit a positive correlation between mass and eccentricity. We interpret this trend as the outcome of planet-planet scattering, representing a transition from collision-dominated interactions among low-mass planets to ejection-dominated interactions among high-mass planets. This framework has important implications for warm Jupiter origins. It suggests that warm Jupiters originate from compact, multi-planet configurations. The dynamical interactions that shape their present-day architectures likely occur near their current semimajor axes, regardless of whether warm Jupiters formed through convergent disk-driven migration or in-situ formation. We argue that several observed properties of warm Jupiter systems, including the eccentricity bimodality, the mass-eccentricity relation, and generally low stellar obliquities, can be explained by this picture. We further predict that not only circular warm Jupiters, but also eccentric warm Jupiters, should frequently have additional planetary companions that are detectable through radial velocity observations. Finally, scattering can produce eccentricities high enough to trigger high-e

In spite of their long detection history, the origin of hot Jupiters remains to be resolved. While multiple dynamical evidence suggests high-eccentricity migration is most likely, conflicts remain when considering hot Jupiters as a population in the context of warm and cold Jupiters. Here, we turn to atmospheric signatures as an alternative mean to test the origin theory of hot Jupiters, focusing on population level trends that arise from post-formation pollution, motivated by the upcoming Ariel space mission whose goal is to deliver a uniform sample of exoplanet atmospheric constraints. We experiment with post-formation pollution by planetesimal accretion, pebble accretion, and disk-induced migration and find that an observable signature of post-formation pollution is only possible under pebble accretion in metal-heavy disks. If most hot Jupiters arrive at their present orbit by high-eccentricity migration while warm Jupiters emerge largely in situ, we expect the atmospheric water abundance of hot Jupiters to be significantly elevated compared to warm Jupiters. We report on the detectability of such signatures and further provide suggestions for future comparative atmospheric char

The unexpectedly large radii of transiting hot Jupiters have led to many proposals for the physical mechanisms responsible for heating their interiors. While it has been shown that hot Jupiters reinflate as their host stars brighten due to heating deep in planetary interiors, young hot Jupiters also exhibit signs of delayed cooling possibly related to heating closer to their surfaces. To investigate this ambiguity, we enhance our previously published hot Jupiter thermal evolution model by adding a parameter that allows for both deep heating and delayed cooling. We fit our thermal evolution models to a homogeneous, physically self-consistent catalog of accurate and precise hot Jupiter system properties in a hierarchical Bayesian framework. We find that hot Jupiters' interior cooling rates are reduced on average by 95\%--98\% compared to simpler anomalous heating models. The most plausible explanation for this inference is substantial shallow heating just below their radiative--convective boundaries that enables reinflation with much weaker deep heating. Shallow heating by Ohmic dissipation and/or temperature advection are therefore important components of accurate models of hot Jupi

Over the past two decades, a coherent picture has emerged of the atmospheric dynamics of hot Jupiters from a combination of three-dimensional general circulation models (GCMs) and astronomical observations. This paradigm consists of hot Jupiters being spin-synchronized due to their close-in orbit, with a resulting large day-to-night irradiation gradient driving a day-to-night temperature contrast. This day-to-night temperature contrast in turn raises day-to-night pressure gradients that are balanced by a circulation with wind speeds on the order of km~s$^{-1}$. The dominant feature of this circulation is a superrotating equatorial jet, maintained by eddy-mean flow interactions that pump momentum into the jet. In this work, I explore the dependence of this circulation paradigm on the initial thermal and dynamical conditions in atmospheric circulation models of hot Jupiters. To do so, I conduct MITgcm simulations of the atmospheric circulation of hot Jupiters with both varying initial wind directions and initial temperature profiles. I find that the results are insensitive to the initial conditions, implying that the current paradigm of hot Jupiter circulation exhibits at most limite

In hot and ultra-hot Jupiters, stellar irradiation is a primary driver of atmospheric circulation and the wave structures that sustain it. We aim to investigate how variations in radiative and dynamical timescales influence global flow regimes, atmospheric circulation efficiency, and the interplay of wave structures across a sample of hot Jupiters. In particular, we explore a previously predicted transition in the global flow regime, where enhanced stellar irradiation suppresses the smaller-scale wave and eddy features that feed into superrotating jets and ultimately leads to simpler, day-to-night dominated flows. We simulate a suite of eight well-studied hot Jupiters with the THOR general circulation model, spanning equilibrium temperatures from about $1100$ K to $2400$ K. We develop a wavelet-based analysis method to decompose simulated wind fields into their underlying wave modes, which we validate on analytical examples. As a preliminary exploration of the flow regime of ultra-hot Jupiters, we perform an additional simulation for WASP-121b, where the mean molecular weight is set to represent an atmosphere dominated by atomic hydrogen. Our results confirm that increasing stellar

This paper presents a comparative analysis of the bulk properties (mass and radius) of transiting giant planets ($\gtrsim$ 8$R_{\oplus}$) orbiting FGKM stars. Our findings suggest that the average mass of M-dwarf Jupiters is lower than that of their solar-type counterparts, primarily due to the scarcity of super-Jupiters ( $\gtrsim$ 2 $M_J$) around M-dwarfs. However, when super-Jupiters are excluded from the analysis, we observe a striking similarity in the average masses of M-dwarf and FGK warm-Jupiters. We propose that these trends can be explained by a minimum disk dust mass threshold required for Jovian formation through core accretion, which is likely to be satisfied more often around higher mass stars. This simplistic explanation suggests that the disk mass has more of an influence on giant planet formation than other factors such as the host star mass, formation location, metallicity, radiation environment, etc., and also accounts for the lower occurrence of giant planets around M-dwarf stars. Additionally, we explore the possibility of an abrupt transition in the ratio of super-Jupiters to Jupiters around F-type stars at the Kraft break, which could be a product of $v$sin$i

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 0.1-1 AU ($\approx$10--365 d) 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 Sun-like host stars (with FGKM spectral types) using 18,587 RV measurements across 40 high-resolution spectrographs. RVs are compiled from the literature and are supplemented with 540 new observations from MINERVA-Australis at Mt. 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 da

The population of hot Jupiters with adjacent planetary companions is small but growing, and inner companions appear to be a nearly ubiquitous outcome within this subset of the exoplanet census. While most hot Jupiters are believed to form via tidal migration, the presence of adjacent companions is not easily explained by this formation mechanism, requiring consideration of additional formation mechanisms such as disk migration and in situ formation. In this work, we explore the possibility of in situ formation for both hot Jupiters and their interior companions. Using numerical simulations performed with the N-body integrator REBOUND, we investigate the growth of interior companions under various assumptions about disk conditions and hot Jupiter final orbital positions. Our results show that if a sufficiently high density of planetary embryos is transported to short orbital radii, it is feasible for both hot Jupiters and their interior companions to form in situ, providing a viable explanation for a subset of observed planetary architectures.

The first discovered extrasolar worlds -- giant, ``hot Jupiter'' planets on short-period orbits -- came as a surprise to solar-system-centric models of planet formation, prompting the development of new theories for planetary system evolution. The near-absence of observed nearby planetary companions to hot Jupiters has been widely quoted as evidence in support of high-eccentricity tidal migration: a framework in which hot Jupiters form further out in their natal protoplanetary disks before being thrown inward with extremely high eccentricities, stripping systems of any close-in planetary companions. In this work, we present new results from a search for transit timing variations across the full four-year Kepler dataset, demonstrating that at least $12\pm6\%$ of hot Jupiters have a nearby planetary companion. This subset of hot Jupiters is expected to have a quiescent dynamical history such that the systems could retain their nearby companions. We also demonstrate a ubiquity of nearby planetary companions to warm Jupiters ($\geq70\pm{16}\%$), indicating that warm Jupiters typically form quiescently. We conclude by combining our results with existing observational constraints to prop

Exploiting the Kepler transit data, we uncover a dramatic distinction in the prevalence of sub-Jovian companions, between systems that contain hot Jupiters (periods inward of 10 days) and those that host warm Jupiters (periods between 10 and 200 days). Hot Jupiters, with the singular exception of WASP-47b, do not have any detectable inner or outer planetary companions (with periods inward of 50 days and sizes down to $2 R_{\rm Earth}$). Restricting ourselves to inner companions, our limits reach down to $1 R_{\rm Earth}$. In stark contrast, half of the warm Jupiters are closely flanked by small companions. Statistically, the companion fractions for hot and warm Jupiters are mutually exclusive, particularly in regard to inner companions. The high companion fraction of warm Jupiters also yields clues to their formation. The warm Jupiters that have close-by siblings should have low orbital eccentricities and low mutual inclinations. The orbital configurations of these systems are reminiscent of those of the low-mass, close-in planetary systems abundantly discovered by the Kepler mission. This, and other arguments, lead us to propose that these warm Jupiters are formed in-situ. There a

Hot Jupiters are typically assumed to be synchronously rotating, from tidal locking. Their thermally-driven atmospheric winds experience Lorentz drag on the planetary magnetic field anchored at depth. We find that the magnetic torque does not integrate to zero over the entire atmosphere. The resulting angular momentum feedback on the bulk interior can thus drive the planet away from synchronous rotation. Using a toy tidal-ohmic model and atmospheric GCM outputs for HD189733b, HD209458b and Kepler7b, we establish that off-synchronous rotation can be substantial at tidal-ohmic equilibrium for sufficiently hot and/or magnetized hot Jupiters. Potential consequences of asynchronous rotation for hot Jupiter phenomenology motivate follow-up work on the tidal-ohmic scenario with approaches that go beyond our toy model.

This study considers the characteristics of planetary systems with giant planets based on a population-level analysis of the California Legacy Survey planet catalog. We identified three characteristics common to hot Jupiters. First, while not all hot Jupiters have a detected outer giant planet companion ($M \sin i$ = 0.3--30 $M_{\textrm{Jup}}$), such companions are ubiquitous when survey completeness corrections are applied for orbital periods out to 40,000 days. Giant harboring systems without a hot Jupiter also host at least one outer giant planet companion per system. Second, the mass distributions of hot Jupiters and other giant planets are indistinguishable. However, within a planetary system that includes a hot Jupiter, the outer giant planet companions are at least $3\times$ more massive than the inner hot Jupiters. Third, the eccentricity distribution of the outer companions in hot Jupiter systems (with an average model eccentricity of $\langle e\rangle=0.34\pm0.05$) is different from the corresponding outer planets in planetary systems without hot Jupiters ($\langle e\rangle=0.19\pm0.02$). We conclude that the existence of two gas giants, where the outermost planet has an

Hot Jupiters may have formed in situ, or been delivered to their observed short periods through one of two categories of migration mechanisms: disk migration or high-eccentricity migration. If hot Jupiters were delivered by high-eccentricity migration, we would expect to observe some "super-eccentric" Jupiters in the process of migrating. We update a prediction for the number of super-eccentric Jupiters we would expect to observe in the Kepler sample if all hot Jupiters migrated through high-eccentricity migration and estimate the true number observed by Kepler. We find that the observations fail to match the prediction from high-eccentricity migration with 94.3% confidence and show that high-eccentricity migration can account for at most ~62% of the hot Jupiters discovered by Kepler.

Understanding the anomalous radii of many transiting hot gas giant planets is a fundamental problem of planetary science. Recent detections of re-inflated warm Jupiters orbiting post-main-sequence stars and the re-inflation of hot Jupiters while their host stars evolve on the main-sequence may help constrain models for the anomalous radii of hot Jupiters. In this work, we present evolution models studying the re-inflation of gas giants to determine how varying the depth and intensity of deposited heating affects both main-sequence re-inflation of hot Jupiters and post-main-sequence re-inflation of warm Jupiters. We find that deeper heating is required to re-inflate hot Jupiters than is needed to suppress their cooling, and that the timescale of re-inflation decreases with increasing heating rate and depth. We find a strong degeneracy between heating rate and depth, with either strong shallow heating or weak deep heating providing an explanation for main-sequence re-inflation of hot Jupiters. This degeneracy between heating rate and depth can be broken in the case of post-main-sequence re-inflation of warm Jupiters, as the inflation must be rapid to occur within post-main-sequence e

Although the formation and the properties of hot Jupiters (with orbital periods $P<10\,$d) have attracted a great deal of attention, the origins of warm Jupiters ($10<P<100\,$d) are less well-studied. Using a transit timing analysis, we present the orbital parameters of five planetary systems containing warm Jupiters, Kepler 30, Kepler 117, Kepler 302, Kepler 487 and Kepler 418. Three of them, Kepler-30 c($M_p=549.4{\pm{5.6}}M_{\oplus}$), Kepler-117 c($M_p=702{\pm{63}}M_{\oplus}$) and Kepler 302 c($M_p=933\pm 527M_{\oplus}$), are confirmed to be real warm Jupiters based on their mass. Insights drawn from the radius-temperature relationship lead to the inference that hot Jupiters and warm Jupiters can be roughly separated by ${T_{\rm eff,c}} =1123.7\pm3.3$ K. Also, ${T_{\rm eff,c}}$ provides a good separation for Jupiters with companion fraction consistent with zero($T_{\rm eff}>T_{\rm eff,c}$) and those with companion fraction significantly different from zero ($T_{\rm eff}<T_{\rm eff,c}$).

Transiting giant planets provide a natural opportunity to examine stellar obliquities, which offer clues about the origin and dynamical histories of close-in planets. Hot Jupiters orbiting Sun-like stars show a tendency for obliquity alignment, which suggests that obliquities are rarely excited or that tidal realignment is common. However, the stellar obliquity distribution is less clear for giant planets at wider separations where realignment mechanisms are not expected to operate. In this work, we uniformly derive line-of-sight inclinations for 47 cool stars ($T_\mathrm{eff}$ $<$ 6200 K) harboring transiting hot and warm giant planets by combining rotation periods, stellar radii, and $v \sin i$ measurements. Among the systems that show signs of spin-orbit misalignment in our sample, three are identified as being misaligned here for the first time. Of particular interest are Kepler-1654, one of the longest-period (1047 d; 2.0 AU) giant planets in a misaligned system, and Kepler-30, a multi-planet misaligned system. By comparing the reconstructed underlying inclination distributions, we find that the inferred minimum misalignment distributions of hot Jupiters spanning $a/R_{*}$