Emily A. Gilbert

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 _⊕ to 33% above 4 R _⊕ : 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 _⊕ across hosts of spectral types: 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.

Stellar photospheric heterogeneity is a dominant astrophysical systematic impacting exoplanet transmission spectroscopy. NASA’s Pandora SmallSat Mission is designed to address this challenge through contemporaneous visible-band photometry and near-infrared spectroscopy of exoplanet host stars. Here, we present an end-to-end simulation study quantifying Pandora’s ability to infer stellar photospheric properties and correct stellar contamination using out-of-transit observations. We construct eight representative stellar activity scenarios and generate 160 simulated Pandora datasets, incorporating time-dependent stellar spectra, instrument response, and noise. Given accurate models, Bayesian retrievals of joint visible photometry (0.4–0.7 μ m) and near-infrared spectroscopy (0.9–1.6 μ m, R ≈ 120) recover photospheric temperatures with typical uncertainties of ≈30 K, with no significant bias. Models with two spectral components (i.e., a quiescent photosphere and spots) are strongly favored in 95% of cases; one-component models are preferred when true spot filling factors fall below a detection threshold of ≈0.3%. We propagate the true and inferred stellar parameters to compute true, inferred, and residual contamination signals under physically motivated spot geometries. For simple spot distributions, contamination signals of 10 ² –10 ³ ppm are reduced to ≲10 ppm—well below Pandora’s expected transmission spectroscopy precision (30–100 ppm). For more complex spot distributions, geometric degeneracies limit deterministic corrections, leaving residual contamination at the 10 ³ ppm level that must be mitigated using additional constraints, such as spot-crossing events and joint stellar–planetary retrievals of transmission spectra. These results define regimes in which stellar contamination can be corrected from stellar observations alone and show how Pandora stellar observations can identify cases where additional information is required.

The TESS Input Catalog (TIC) was built on Gaia Data Release 2 (DR2). To date, there has not been an update to the TIC to incorporate Gaia Data Release 3 (DR3) IDs. In this Research Note, we outline how we cross-matched the TIC with Gaia DR3 IDs, its immediate applications to exoplanet research, and lessons learned when dealing with such large datasets. A full TIC/Gaia DR3 cross-match table is available for download on the Exoplanet Follow-up Observing Program website, and a Jupyter Notebook with instructions to reproduce the table is available on GitHub.

Pandora is a SmallSat mission dedicated to understanding exoplanets and their host stars by disentangling the impact of stellar heterogeneity on exoplanet transmission spectra. Selected as a NASA Astrophysics Pioneers mission in 2021, Pandora will provide simultaneous long-term visible photometric monitoring (0.4–0.7 μ m) and low-resolution near-infrared (NIR) spectroscopy (0.9–1.6 μ m) of transiting systems for the purposes of monitoring host star variability and characterizing exoplanetary atmospheres. Pandora’s year-long prime mission from 2026 to 2027 coincides with the middle of a decade defined by targeted efforts for atmospheric characterization of exoplanets, offering a key opportunity to leverage this new resource to maximize science with JWST and other observatories. Here we investigate Pandora’s anticipated performance for the general exoplanet population accessible to transit spectroscopy, from hot Jupiters to temperate sub-Neptunes. By modeling the atmospheres of five test cases broadly consistent with the bulk properties of HD 209458b, HD 189733b, WASP-80 b, HAT-P-18 b, and K2-18 b, we find that Pandora may provide abundance constraints as precise as ∼1.0 dex for main atmospheric absorbers such as H ₂ O and CH ₄ . Then, we explore the synergies between Pandora and JWST. Our results suggest that targets with JWST data in the NIR can benefit from the addition of Pandora observations and result in more reliable abundance estimates than with JWST data alone. Moreover, Pandora can serve the community by providing precursory observations of targets of interest for JWST atmospheric characterization. We conclude by outlining strategies for the use of Pandora as a standalone observatory and in synergy with JWST.

Measurements of physical parameters for stars and (exo)planets are often quoted in units normalized to the Sun and/or Earth. The nominal total solar irradiance , S ⊙ N , while based on a current best estimate with uncertainties, was adopted to be an exact reference value of 1361 W m ⁻² by IAU 2015 Resolution B3, corresponding to “ the mean total electromagnetic energy from the Sun, integrated over all wavelengths, incident per unit area per unit time at distance 1 au. ” In the planetary and exoplanetary science literature, the units employed for “flux,” “insolation,” “instellation,” etc., are often cumbersome or inconsistent. To simplify the quoting of irradiance units for astronomical applications, we introduce the portmanteau solirad, short for solar irradiance, as an abbreviated version of the longer IAU term “nominal total solar irradiance.” The solirad (So) is a unit of irradiance, where 1 solirad = 1 So = 1361 W m ⁻² , equivalent to the IAU nominal total solar irradiance, and to an apparent bolometric magnitude of m _bol ≃ −26.832 mag (per IAU 2015 Resolution B2).

Earth-sized planets transiting M dwarf stars present one of the best opportunities with current facilities for studying the atmospheric and bulk compositions of terrestrial worlds. Here, we statistically validate five new transiting Earth and super-Earth sized planets orbiting M dwarf stars using a combination of light curves from the Transiting Exoplanet Survey Satellite, multicolor observations from Palomar and Las Cumbres Observatory, high-resolution imaging, and stellar spectroscopy. The sample includes TOI-5716 b, an Earth-sized planet ( R _p = 0.96 ± 0.05 R _⊕ ) with a 6.766 day orbit around a metal-poor thin-disk star ([Fe/H] = −0.54 ± 0.10); TOI-5728 b, a super-Earth ( R _p = 1.31 ± 0.05 R _⊕ ) on an 11.497 day orbit; and TOI-5736 b, a larger planet ( R _p = 1.56 ± 0.07 R _⊕ ) with an ultrashort period of just 0.649 days. We also statistically validate a multiplanet system, TOI-5489, hosting two similarly sized super-Earths: TOI-5489 b ( R _p = 1.40 ± 0.05 R _⊕ ) and TOI-5489 c ( R _p = 1.28 ± 0.07 R _⊕ ) with orbital periods of 3.152 and 4.921 days, respectively. Due to their longer orbital periods, TOI-5716 b and TOI-5728 b both have equilibrium temperatures ≤ 400 K, making them useful test cases for studies of atmospheric mass loss. If TOI-5728 b is confirmed to have an Earth-like bulk composition, it would join the very small sample of rocky planets orbiting mid-to-late M dwarfs that lie below the cosmic shoreline and therefore may have retained high mean molecular weight atmospheres.

Young planets with mass measurements are particularly valuable in studying atmospheric mass-loss processes, but these planets are rare and their masses difficult to measure due to stellar activity. We report the discovery of a planetary system around TOI-6109, a young, 75 Myr-old Sun-like star in the Alpha Persei cluster. It hosts at least two transiting Neptune-like planets within 10 day orbital periods. Using three TESS sectors, 30 CHEOPS orbits, and photometric follow-up observations from the ground, we confirm the signals of the two planets. TOI-6109 b has an orbital period of P = 5.690 4 − 0.0004 + 0.0004 days and a radius of R = 4.8 7 − 0.12 + 0.16 R _⊕ . The outer planet, TOI-6109 c has an orbital period of P = 8.538 8 − 0.0005 + 0.0006 days and a radius of R = 4.8 3 − 0.06 + 0.07 R _⊕ . These planets orbit just outside a 3:2 mean motion resonance. The near-resonant configuration presents the opportunity to measure the planet’s mass via TTV measurements and to bypass difficult RV measurements. Measuring the masses of the planets in this system will allow us to test theoretical models of atmospheric mass loss.

We present the discovery by the TESS mission of one transiting Neptune-sized planet, TOI-6223 b, and two transiting super-Earths, TOI-1743 b and TOI-5799 b. We validate these planets using a statistical validation method, multi-color light curves, and other ancillary observations. We combined TESS and ground-based photometric data to constrain the physical properties of the planets. TOI-6223 b is slightly larger than Neptune R_p = 5.12_−0.25^+0.24 R_⊕) orbiting an early M dwarf in 3.86 days, and it has an equilibrium temperature of T_eq = 714 ± 14 K. TOI-1743 b orbits its mid-dwarf star every 4.27 days. It has a radius of R_p = 1.83_−0.10^+0.11 R_⊕ and an equilibrium temperature of T_eq = 485₋₁₃⁺¹⁴. TOI-5799 b has a radius of R_p = 1.733_−0.090^+0.096 R_⊕ and an equilibrium temperature of T_eq = 505 ± 16 K. It orbit around an M2 dwarf in 4.17 days. We also present the discovery of an additional transiting planet, TOI-5799 c, which we identified in the TESS data and validated using the SHERLOCK pipeline. TOI-5799 c is a super-Earth with a radius of R_p = 1.76_−0.10^+0.11 R_⊕. Its orbital period and its equilibrium temperature are 14.01 days and T_eq = 337 ± 11 K, respectively, which place it near the inner edge of the habitable zone of its star. We show that these planets are suitable for both radial velocity follow-up and atmospheric characterization. They orbit bright (K_mag) early M dwarfs, making them accessible for precise mass measurements. The combination of the planet sizes and stellar brightness of their host stars also make them suitable targets for atmospheric exploration with the JWST. Such studies may provide insights into planet formation and evolution, as TOI-1743 b, TOI-5799 b, and TOI-5799 c lie within what is known as the radius valley, while TOI-6223 b is located on the Neptunian ridge in the period-radius plane.