arXiv subjects

Khalid Barkaoui

Publications and source records attributed to Khalid Barkaoui.

At least 19 recordsLinked to original sources

arXiv2026

Discovery and Characterization of the TOI-4468 Planetary System: A Transiting Hot Jupiter With a Lone Nearby Outer Companion

We report the discovery of two planets, a hot Jupiter and a nearby outer sub-Neptune, orbiting the star TOI-4468. This system is unique among the current exoplanet census in that it features a close outer companion to a hot Jupiter without an accompanying inner companion. By jointly fitting radial velocity measurements taken with the NEID spectrograph and transit photometry from TESS and several ground-based observatories, we constrain the orbital periods, masses, and radii of these two planets. We confirm the planetary nature of the hot Jupiter TOI-4468 b ($R = 1.01 R_J$, $m = 0.54 M_J$, $P = 2.77$ days). We also validate the outer planet TOI-4468 c ($R = 0.28 R_J$, $P = 7.01$ days) statistically, incorporating constraints from ground-based observations. We also identify, but cannot confirm, an additional radial velocity signal which may be due to an outer giant in this system with an orbital period of 624 days. From the observed geometry of this system, we argue that it must never have encountered an early secular resonance that is thought to excite the mutual inclination of other hot Jupiter/outer companion systems. We discuss the possibility of an undetected inner companion, as well as potential implications for hot Jupiter formation.

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arXiv2026

Assessing the Impact of High-Resolution Imaging on Statistical Validation of TESS Planet Candidates

High-resolution imaging is widely used to constrain false-positive scenarios in exoplanet validation, but it is a finite follow-up resource that reaches only a subset of candidates, and its population-level impact on validation outcomes has not been quantified through controlled removal experiments. Using an automated pipeline built on TRICERATOPS, we compute the false-positive probability (FPP) of 443 TESS planet candidates. For the 264 planet candidates with high-resolution imaging observations, we compute FPP with and without the corresponding contrast curves, allowing us to quantify the impact of the additional data. We find that 72% of 68 contrast-curve bearing validated planets would fail validation without their adopted contrast curves. The fraction requiring imaging decreases with increasing planet size, from 100% below $1.7~R_\oplus$ to $33\%$ above $4~R_\oplus$: within our sample and TRICERATOPS-based analysis, the availability of high-resolution imaging directly limits the yield of small-planet validation and the supply of validated targets for atmospheric characterization. Our analysis statistically validates 64 new TESS planets with sizes spanning 0.94 to 7.83 $R_\oplus$ across hosts of spectral type M through F. Four of these are highly amenable to JWST observations based on the transmission and emission spectroscopy metrics, and each achieves validation only with its imaging constraint.

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arXiv2026

A Pair of Warm Saturn-mass Planets near the 2:1 Mean Motion Resonance around TOI-3850

Warm Jupiters, with orbital periods of $10$--$200~\rm{days}$ and radii exceeding $8~R_{\oplus}$, are a relatively understudied class of exoplanets occupying the parameter space between hot Jupiters and more widely separated, colder Jupiter analogs. In this work, we report the detection of a multi-planet warm Jupiter system around TOI-3850 (TIC-143008050), a moderately active, near-solar metallicity G0 dwarf star observed by TESS in Sectors 15, 21, 41, 48 and 75. Initially, a single candidate planet was discovered by TESS, displaying transit timing variations (TTVs) with an amplitude of $\sim 1~\rm hr$ and a super-period of $513~\rm days$. Through a combination of transit photometry, radial velocity observations with MAROON-X, and TTV modeling, we identify two planets: TOI-3850 b $(P_b=14.484\pm0.002~\mathrm{days},~ M_b =112\pm20~M_{\oplus},~e_b = 0.018\pm0.008, R_b = 12.07\pm0.09~R_{\oplus}, ~T_{\rm{eq}}=841\pm10~\rm{K})$, a transiting warm Jupiter, and TOI-3850 c $(P_c=29.85\pm0.01~\mathrm{days},~ M_c =90\pm15~M_{\oplus},~e_c < 0.015, ~T_{\rm{eq}}=661\pm7~\rm{K})$, a non-transiting, Saturn-mass companion. The two planets lie wide of the 2:1 mean motion resonance $(P_c/P_b \approx 2.06)$, consistent with a formation history involving disk-driven migration. $N$-body integrations indicate that TOI-3850 c may begin to transit on decadal timescales, while TOI-3850 b remains a promising target for follow-up atmospheric characterization.

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arXiv2026

Stellar Multiplicity of M Dwarfs with Short-period Giant Planets, and the Characterization of TOI-5628Ab

Binary stars are ubiquitous, yet it remains unclear how wide-orbit stellar companions influence the formation of hot Jupiters, particularly around M dwarfs. Here, we first report the discovery of TOI-5628Ab, a giant planet transiting a mid-type M dwarf ($M_\ast=0.36\pm0.02\ M_\odot$) every 4.34 days, accompanied by an associated white dwarf TOI-5628B ($M_{\rm WD}=0.59\pm0.16\ M_\odot$) at a projected distance of about 2,500 AU. Using TESS, ground-based photometry and SPIRou RVs, we constrain the planet radius to $0.74\pm0.04\ R_J$ and mass to $0.09\pm0.04\ M_J$, with a $3\sigma$ upper limit of $0.22\ M_J$. Building on this system, we further conduct a homogeneous systematic search for co-moving stellar companions with projected semi-major axis between 100 and 10,000 AU around all M dwarfs with confirmed giant planets with periods smaller than 10 days and radii larger than 0.7 $R_J$, as well as a group of field M stars with stellar properties similar to the planet sample, based on the stellar kinematics from Gaia DR3. We measure a stellar multiplicity of $34.2\pm9.5\%$ for M dwarfs hosting short-period giant planets, which is substantially higher than the fraction of $5.3\pm3.7\%$ for the field M stars by approximately a factor of 6. Our results suggest that wide-orbit stellar companions tend to promote the formation of short-period giant planets around M stars with masses $0.21 \leq M_\ast\leq 0.64\ M_\odot$, and high-eccentricity migration may play an important role in producing such systems.

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arXiv2026

Size, shape, density, and atmospheric limit of (50000) Quaoar revealed from 14 years of stellar occultation

We present results from 28 stellar occultations by the large Trans-Neptunian Object (50000) Quaoar registered between 2018 and 2025. By performing a joint analysis of this occultation data-set, along with other 9 published events, we were able to fit an oblate ellipsoid shape, with equatorial semi-axes, a and b of 566.1+2.5-2.2 km, and a polar semi-axis, c, of 511.2+3.6-3.7 km. It provides an equivalent volumetric diameter of 1094.4 +/- 4.6 km and polar oblateness of 0.097 +/- 0.011. Considering an absolute magnitude of H = 2.79 +/- 0.35, we derive a geometric albedo of pV = 0.125 +/- 0.038. We have derived new upper limits to the surface pressure of a CH4 atmosphere of 0.15 nbar (1-sigma) and 0.65 nbar (3-sigma). We also provide a table with the 36 new astrometric positions for Quaoar. Using the new system mass derived from Weywot's orbit around Quaoar, we calculated a density of 1.760 +/- 0.109 g/cm3. Moreover, from the derived size and rotation period (8.8394 +/- 0.0002 hours (Ortiz et al. 2003)), we calculate that, if Quaoar is in Maclaurin hydrostatic equilibrium state, it would have a density of 1.859 +/- 0.200 g/cm3. This result, within the error bars, is compatible with the value we found. Therefore, this work shows that Quaoar can be a Maclaurin object, being eligible as a dwarf planet.

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arXiv2026

ASTEP confirmation of a pair of long-period Jupiter-sized planets with extremely low densities transiting TOI-791

Gas giant planets with periods $20~<~P~<~300~\rm days$ orbiting Sun-like stars are a relatively uncommon outcome of planetary formation, and key questions about the nature and formation of this sub-population remain unanswered. Theoretical models for the location of their formation (in- or ex-situ) and for their subsequent migration predict different outcomes in terms of planet masses and eccentricities, indicating that observations have a key role to play in disentangling their histories. In this work we present the discovery and confirmation of a pair of long-period Jupiter-sized planets transiting an F7 star: TOI-791 b is a $0.993\pm0.033\rm~R_{Jup}$ planet on a $139.29931_{-0.00012}^{+0.00011}~\rm day$ orbit, and TOI-791 c, a $1.155\pm0.040\rm ~R_{Jup}$ planet on a $232.01570_{-0.00071}^{+0.00067}~\rm day$ orbit. The two planets are within 0.07% of a second-order 5:3 period commensurability leading to transit timing variations (TTVs) of up to 50 minutes. We confirm their planetary nature using ground-based photometry, including multiple full detections of the $>11~\rm hr$ transits of both TOI-791 b and c from Antarctica with ASTEP, making these the longest-duration transits ever observed in their entirety from the ground. Our detailed analysis of the TTV signal allows us to measure dynamical masses for both planets, which yield densities of $\rho_{\rm b}=0.038\pm0.008 \rm ~g~cm^{-3}$ and $\rho_{\rm c}=0.047\pm0.006 \rm ~g~cm^{-3}$, indicating that TOI-791~b and c are two of the lowest density giant planets ever detected. While these measurements are robust, further follow-up is needed to fully characterise the TTV signal and the architecture of the system.

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arXiv2026

A Previously Underexplored Regime in TESS: Minute-Scale Eclipses Reveal Ten White Dwarf-Cool M-Dwarf Binaries

Short-period white-dwarf (WD) binaries are post-common-envelope systems that constrain orbital shrinkage, envelope evolution, and the survival of low-mass companions. We report the discovery and confirmation of ten fully eclipsing short-period WD + cool M-dwarf binaries identified through a tailored search for minute-scale eclipses in Transiting Exoplanet Survey Satellite (TESS) high-cadence data and validated with SPECULOOS multi-band photometry. The systems have orbital periods of a few hours and companions with effective temperatures of 2700-3400 K. These discoveries demonstrate that TESS contains a previously underexplored population of compact WD binaries whose short-duration, high-frequency, and often diluted eclipse signals are not efficiently recovered by standard transit-search pipelines. Whereas the literature contained only one eclipsing WD+M binary reported as a TESS-based discovery, our pilot search of $\sim3.7\times10^4$ Gaia-selected WDs yields ten new confirmed systems, increasing the TESS-discovered sample by an order of magnitude. SPECULOOS follow-up confirms the eclipses occur on target and uses chromatic eclipse dilution to distinguish stellar from substellar companions. We combine multi-band eclipse photometry with Bayesian spectral energy distribution modeling to derive self-consistent WD and companion parameters. The resulting systems expand the known population of fully eclipsing WD+M binaries and notably double the number of systems in temperature regimes corresponding to M4 and M7 companions. This work establishes a scalable framework for identifying compact WD binaries in time-domain photometric surveys. Applied to TESS archival data across the full Gaia WD-candidate catalog ($\sim1.3\times10^6$ sources), this approach opens the prospect of assembling a population large enough to constrain post-common-envelope evolution and the stellar-substellar transition.

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arXiv2026

Uncovering the Rapidly Evolving Orbits of the Dynamic TOI-201 System

Studying planetary interactions in exoplanet systems informs theories of planet formation and evolution, providing essential context for understanding our own solar system. We combine spectroscopy, transit photometry, transit timing variations, and astrometry to characterize the TOI-201 system. The co-transiting system consists of a super-Earth, warm Jupiter, and massive companion at 5.8, 53, and 2900 day orbital periods, respectively. We perform dynamical simulations to study the past and future of the system. von-Zeipel-Kozai-Lidov oscillations emerge as the most plausible scenario to explain the outer companion's high orbital eccentricity, with planet-planet scattering a possible but less likely contender. Due to non-zero mutual inclinations between the planets, the system is visibly evolving on very short timescales, with the current co-transiting configuration ending in 200 years.

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arXiv2026

TOI-7169 b: A Hot Jupiter Transiting a Metal-Poor Star

Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the properties of planets born in low-metallicity environments may differ from those with metal-rich origins. We present the discovery and characterization of TOI-7169 b (TIC 372048733 b), a hot Jupiter that is orbiting a spectroscopically-confirmed metal-poor ([Fe/H] = -0.72 +/- 0.05) host star. Based on photometry from TESS and follow-up ground-based imaging, we measure an orbital period of 3.4373125 d and a planetary radius of 1.475 +/- 0.029 R_Jup. We use TRES spectroscopy to determine a mass for TOI-7169 b of 0.41 +/- 0.14 M_Jup. The planet is therefore inflated, with a low density of 0.159 +0.055/-0.054 g/cm^3. We also characterize the host star, showing that TOI-7169 is ancient (12.3 +/- 0.6 Gyr) and alpha-enhanced ([alpha/Fe] ~ 0.3), but with a Galactocentric orbit that is confined to the thin disk. TOI-7169 is perhaps the oldest and most metal-poor star currently known to host a transiting giant planet. Future transmission spectroscopy probing the atmosphere of TOI-7169 b may provide insight into the effect of metallicity on the physical properties of giant planets.

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arXiv2026

TOI-4616 b: a benchmark Earth-sized planet transiting a nearby M4 dwarf

Rocky exoplanets are particularly abundant around M-type stars. Their small radii and low luminosities provide favourable conditions for detecting transiting terrestrial planets and probing their atmospheric properties. We report the discovery and statistical validation of TOI-4616 b, an Earth-sized planet transiting a nearby mid-M dwarf observed by the Transiting Exoplanet Survey Satellite (TESS). We confirm the planetary nature of the signal and determine the system parameters by combining TESS photometry with ground-based multi-band transit observations, high-resolution imaging, and optical and near-infrared spectroscopy. The host star lies at a distance of 28.10 +(-) 0.07 pc and has a radius of 0.1889 +(-)0.0096 solar radii, a mass of 0.1881 +(-) 0.0094 solar masses, and an effective temperature of 3150 +(-) 75 K. TOI-4616 b has a radius of 1.22 Earth radii and an orbital period of 1.55 days. The planet receives an incident flux of approximately 40 times that of Earth, corresponding to an equilibrium temperature of about 525 K. This places TOI-4616 b in a regime intermediate between Earth-sized planets orbiting early M dwarfs and those around ultra-cool hosts. Statistical validation with the TRICERATOPS framework, supported by high-resolution imaging and chromatic transit constraints, yields a false-positive probability of 0.0135, below the recommended validation threshold of 0.015, confirming TOI-4616 b as a validated planet. Owing to its proximity to Earth, well-constrained stellar properties, and extensive multi-band follow-up, TOI-4616 b constitutes a valuable benchmark system for comparative studies of terrestrial planets around mid-M dwarfs and for future atmospheric investigations.

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arXiv2026

PLATOSpec's first results: Three new transiting warm Jupiters from the WINE survey TIC 147027702, TIC 245076932 and TIC 87422071

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-eccentric orbit ($e = 0.13 \pm 0.05$) with a period of 44.4 days and has a mass of $1.09^{+0.07}_{-0.13}$ M$_J$ and a radius of $0.98 \pm 0.06$ R$_J$. TIC 245076932b has a moderately low mass of $0.51 \pm 0.05$ M$_J$, a radius of $0.97 \pm 0.05$ R$_J$, and an eccentric orbit ($e = 0.43 \pm 0.02$) with a period of 21.6 days. TIC 87422071b has a mass of $1.29 \pm 0.10$ M$_J$, a radius of $0.97 \pm 0.08$ R$_J$, and has a slightly eccentric orbit ($e = 0.12 \pm 0.07$) 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.

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arXiv2026

The Orbital Eccentricity--Radius Distribution for Warm, Single Planets in TESS

We characterize the radius-dependent eccentricity distribution of 219 warm (P = 8--50 days) systems with only one transiting planetary candidate identified during Sectors 1-69 of the TESS mission. Using the ``photoeccentric effect'' in a hierarchical Bayesian framework, we first model the population using discrete planetary size bins (sub-Neptunes, sub-Saturns, and Jovians). We then develop a continuous mixture model with weights governed by a logistic sigmoid function of radius. We find that the warm-single population is best described by two components: a dominant low-eccentricity mode ( = 0.039-0.038+0.018) and a secondary dynamically excited mode ( = 0.466-0.068+0.067). The fraction of planets belonging to this high-eccentricity component increases strongly with planet radius, characterized by a transition at a break radius of R_br = 9.2-1.1+1.9 R_e. This trend places warm sub-Saturns predominantly on the same low-eccentricity track as sub-Neptunes. In contrast, warm Jovians (8--16 R_e) are frequently eccentric, with 65-12+13% of the population in the high eccentricity mode. Under the assumption of a two-component model, we see tentative evidence for a bimodal Jovian distribution at ~2.7 sigma. Finally, we identify a non-negligible tail of highly eccentric sub-Neptunes (1--4 R_e), which comprise 16.2-6.4+5.2% of the population, consistent with excitation by non-transiting external companions.

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arXiv2026

Two warm sub-Saturn mass planets identified from the TESS Full Frame Images

Context. Characterization of warm giants is crucial to constrain giant planet formation and evolution. Measuring the mass and radius of these planets, combined with their moderated irradiation, allows us to estimate their planetary bulk composition, which is a key quantity to comprehend giant planet formation and structure. Aims. We present the discovery of two transiting warm giant planets orbiting solar-type stars from the Transiting Exoplanet Survey Satellite (TESS), which were characterized by further spectroscopic and photometric ground-based observations. Methods. We performed a joint analysis of photometric data with radial velocities to confirm and characterize TOI-883 b and TOI-899 b, two sub-Saturns orbiting solar-like stars. Results. TOI-883 b and TOI-899 b have masses of $0.123 \pm 0.012$ $M_J$ and $0.213 \pm 0.024$ $M_J$, radius of $0.604 \pm 0.028$ $R_J$ and $0.991 \pm 0.044$ $R_J$, periods of $10.06$ d and $12.85$ d and equilibrium temperature of $1086 \pm 19$ K and $1040 \pm 19$ K, respectively. Conclusions. While having similar masses, orbital periods and stellar host properties, these planets seem to have different internal compositions, which could point to distinct formation histories. Both planets are suitable targets for atmospheric studies to further constrain formation scenarios of planets in the Neptune-Saturn mass range

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arXiv2026

TIC-65910228 b / NGTS-38 b, a 180 day transiting warm super-Jupiter

We present the discovery of TIC-65910228 b / NGTS-38 b, a giant exoplanet with a radius of $1.081\pm0.047$ R$_\text{J}$ and a mass of $4.78_{-0.37}^{+0.39}$ M$_\text{J}$ on a long-period ($180.52797\pm0.00036$ day), moderately eccentric ($e=0.3086\pm0.010$) orbit transiting a bright (V=$10.230\pm0.020$ mag) metal rich ([Fe/H]=$0.33\pm0.09$, 'dex') F6V-F7V type host star. The planet was initially detected from a single transit in TESS Sector 33. A photometric monitoring campaign of 228 nights with NGTS detected a transit egress of the planet, which together with spectroscopic radial velocity monitoring with CORALIE and HARPS identified an orbital period of ~180.5,d. These radial velocity measurements also showed the mass of the companion to be planetary. Additional transit observations coordinated by the TESS follow-up observing program allowed further confirmation and refinement of this period. With its relatively cool equilibrium temperature of $457\pm11$ K, NGTS-38 b joins a small but growing population of well characterised transiting warm-Jupiters and has one of the longest periods of any discovered to date. The target is situated in the LOPS2 field of the upcoming PLATO mission which will allow for greater refinement of the system parameters and potential for the discovery of additional companions too small and/or too long-period to be seen by TESS or NGTS. NGTS-38 b's bright host star and wide orbital separation make it an attractive target for further study, including potential measurement of its spin-orbit alignment or targeted exomoon/ring searches.

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arXiv2026

TOI-6692b: An eccentric 130 day period giant planet with a single transit from TESS

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 (cTOI) 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 6.5m 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 multi-night data and provide an updated ephemeris for future monitoring. TOI-6692 b is one of 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 few TESS single transit targets that have its period 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.

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arXiv2026

The Occurrence Rate of Nearby Planetary Companions to Hot Jupiters

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 jupiters with nearby companions may have cold companions at a rate similar to that of other hot jupiters. Comprehensive transit, radial velocity, and stellar obliquity measurements in hot jupiter systems with nearby companions will be necessary to fully account for the relative prevalence of proposed hot jupiter formation pathways.

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arXiv2026

Two temperate Earth- and Neptune-sized planets orbiting fully convective M dwarfs

As the diversity of exoplanets continues to grow, it is important to revisit assumptions about habitability and classical HZ definitions. In this work, we introduce an expanded 'temperate' zone, defined by instellation fluxes between $0.1<S/\mathrm{S}_\oplus<5$, thus encompassing a broader range of potentially habitable worlds. We also introduce the TEMPOS survey, which aims to produce a catalogue of precise radii for temperate planets orbiting M dwarfs with $T_\mathrm{eff}\leq3400\,$ K. This work reports the discovery and characterisation of two planets in this temperate regime orbiting mid-type M dwarfs: TOI-6716\,b, a $0.98\pm0.07\,\mathrm{R}_\oplus$ planet orbiting its M4 host star ($R_\star=0.231\,\pm0.015\mathrm{R}_\odot$, $M_\star=0.223\pm0.011\,\mathrm{M}_\odot$, $T_\mathrm{eff}=3110\pm80\,\mathrm{K}$) with a period $P=4.7185898^{+0.0000054}_{-0.0000041}\,\mathrm{d}$, and TOI-7384 b, a $3.56\pm0.21\,\mathrm{R}_\oplus$ planet orbiting an M4 ($R_\star=0.319\,\pm0.018\mathrm{R}_\odot$, $M_\star=0.318\pm0.016\,\mathrm{M}_\odot$, $T_\mathrm{eff}=3185\pm75\,\mathrm{K}$) star every $P=6.2340258^{+0.0000034}_{-0.0000036}\,\mathrm{d}$. The radii of TOI-6716 b and TOI-7384 b have precisions of $6.8\%$ and $5.9\%$ respectively. We validate these planets with multi-band ground-based photometric observations, high-resolution imaging and statistical analyses. We find these planets to have instellation fluxes close to the inner (hotter) edge of the temperate zone, with $4.4\pm1.1\,\mathrm{S}_\oplus$ and $4.9\pm1.1\,\mathrm{S}_\oplus$ for TOI-6716 b and TOI-7384 b respectively. Also, with a predicted TSM similar to the TRAPPIST-1 planets, TOI-6716 b is likely to be a good rocky-world JWST target, should it have retained its atmosphere.

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arXiv2025

TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star

We present the discovery and validation of TOI-7166b, a 2.01+/-0.05R_Earth planet orbiting a nearby low-mass star. We validated the planet by combining TESS and multi-color high-precision photometric observations from ground-based telescopes, together with spectroscopic data, high-contrast imaging, archival images, and statistical arguments. The host star is an M4-type dwarf at a distance of ~35 pc from the Sun. It has a mass and a radius of Ms=0.190+/-0.004M_Sun and Rs=0.222+/-0.005R_Sun, respectively. TOI-7166b has an orbital period of 12.9 days, which places it close to the inner edge of the Habitable Zone of its host star, receiving an insolation flux of Sp=1.07+/-0.08S_Earth and an equilibrium temperature of Teq=249+/-5K (assuming a null Bond albedo). The brightness of the host star makes TOI-7166 a suitable target for radial velocity follow-up to measure the planetary mass and bulk density. Moreover, the physical parameters of the system including the infrared brightness (Kmag = 10.6) of the star and the planet-to-star radius ratio (0.0823+/-0.0012) make TOI-7166b an exquisite target for transmission spectroscopic observations with the JWST, to constrain the exoplanet atmospheric compositions.

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