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1. TOI-4495: A Pair of Aligned, Near-resonant Sub-Neptunes That Likely Experienced Overstable Migration

   https://doi.org/10.3847/1538-3881/ae346d  

   Wang_王, Mu-Tian 牧天; Dai_戴, Fei 飞; Liu_刘, Hui-Gen 慧根; Masuda, Kento; Howard, Andrew W; Halverson, Samuel; Isaacson, Howard; Zhang, Elina Y; Goldberg, Max; Teng, Huan-Yu; et al (February 2026, The Astronomical Journal)

   Abstract We report the discovery of a sub-Neptune and a Neptune-like planet (R ${}_b=2.48_{-0.10}^{+0.14}$ R_⊕,R ${}_c=4.03_{-0.15}^{+0.23}$ R_⊕) orbiting the F-type star TOI-4495. The planets have orbital periods of 2.567 and 5.185 days, lying close to a 2:1 mean-motion resonance (MMR). Our photodynamical analysis of the TESS light curves constrains the planetary masses toM_b = 7.7 ± 1.4M_⊕and M_c = 23.2 ± 4.7M_⊕. The measured masses and radii indicate the presence of volatile-rich gaseous envelopes on both planets. The Rossiter–McLaughlin effect and the Doppler shadow of TOI-4495 c reveal a well-aligned orbit with a projected stellar obliquity of $\lambda =-2.3_{-7.8}^{+8.3}°$ . Combined with the low mutual inclination constrained by the photodynamical analysis (ΔI < 8.7°), the planetary orbits are likely coplanar and aligned with the host star’s spin axis. We show that the planets are near, but not in, the 2:1 MMR, with a circulating resonant angle. We also find substantial free eccentricity for the inner planet, TOI-4495 b ( $e_b=0.078_{-0.013}^{+0.02}$ ). Given the observed proximity to the 2:1 resonance and the more massive outer planet, TOI-4495 b and c are particularly susceptible to resonant overstability, which in turn can explain the observed eccentricity by converting resonantly excited eccentricity into free eccentricity. However, additional mechanisms (e.g., planetesimal scattering) may be required to further excite the eccentricity by ∼4%. To prevent tidal damping from reducing the eccentricity below the observed level over the star’s lifetime (1.9 Gyr), the reduced tidal quality factor of TOI-4495 b must be $Q^{\prime }\gtrsim 10^5$ , consistent with the presence of a thick envelope on the planet. 

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2. Spot-crossing Variations Confirm a Misaligned Orbit for a Planet Transiting an M Dwarf

   https://doi.org/10.3847/1538-3881/adf72f  

   Tamburo, Patrick; Yee, Samuel W; García-Mejía, Juliana; Charbonneau, David; Bieryla, Allyson; Collins, Karen A; Shporer, Avi (September 2025, The Astronomical Journal)

   Abstract TOI-3884 b is an unusual 6.4R_⊕planet orbiting an M4 host, whose transits display large and persistent spot-crossing events. We used theTierrasObservatory to monitor both the long-term photometric variability of TOI-3884 and changes in the spot-crossing events across multiple transits of the planet. We show that the star rotates with a period of 11.020 ± 0.015 days. We simultaneously model the rotational modulation of the star and variations in transit shapes that arise due to rotation of the spot, allowing us to determine the true stellar obliquity,ψ_⋆. The data are best described by a planet on a misaligned orbit around a highly inclined star (ψ_⋆ =  ${77\stackrel{\text{°}}{.}4}_{-2\stackrel{\text{°}}{.}5}^{+2\stackrel{\text{°}}{.}3}$ ;i_⋆ =  ${22\stackrel{\text{°}}{.}3}_{-1\stackrel{\text{°}}{.}6}^{+1\stackrel{\text{°}}{.}8}$ ) that hosts a large polar starspot (r_spot =  ${31.2^{\circ }}_{-1.9^{\circ }}^{+2.4^{\circ }}$ ;λ_spot =  80 $\stackrel{\text{°}}{.}$ 5 ± 1 $\stackrel{\text{°}}{.}$ 2). Archival photometry from the Zwicky Transient Facility suggests that this polar spot has persisted on TOI-3884 for at least seven years. The TOI-3884 system provides a benchmark for studying the evolution of a polar spot on an M dwarf. 

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3. The Aligned Orbit of a Hot Jupiter around the M Dwarf TOI-4201

   https://doi.org/10.3847/2041-8213/ad5967  

   Gan, Tianjun; Wang, Sharon X; Dai, Fei; Winn, Joshua N; Mao, Shude; Xu, Siyi; Pallé, Enric; Bean, Jacob L; Brady, Madison; Brown, Nina; et al (July 2024, The Astrophysical Journal Letters)

   Abstract Measuring the obliquities of stars hosting giant planets may shed light on the dynamical history of planetary systems. Significant efforts have been made to measure the obliquities of FGK stars with hot Jupiters, mainly based on observations of the Rossiter–McLaughlin effect. In contrast, M dwarfs with hot Jupiters have hardly been explored because such systems are rare and often not favorable for such precise observations. Here, we report the first detection of the Rossiter–McLaughlin effect for an M dwarf with a hot Jupiter, TOI-4201, using the Gemini-North/MAROON-X spectrograph. We find TOI-4201 to be well aligned with its giant planet, with a sky-projected obliquity of $\lambda =-{3.0}_{-3.2}^{+3.7}°$ and a true obliquity of $\psi ={21.3}_{-12.8}^{+12.5}°$ with an upper limit of 40^◦at a 95% confidence level. The result agrees with dynamically quiet formation or tidal obliquity damping that realigned the system. As the first hot Jupiter around an M dwarf with its obliquity measured, TOI-4201b joins the group of aligned giant planets around cool stars (T_eff< 6250 K), as well as the small but growing sample of planets with relatively high planet-to-star mass ratio (M_p/M_*≳ 3 × 10⁻³) that also appear to be mostly aligned. 

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4. Observation of a pseudoscalar excess at the top quark pair production threshold

   https://doi.org/10.1088/1361-6633/adf7d3  

   Collaboration, The CMS (August 2025, Reports on Progress in Physics)

   Abstract A search for resonances in top quark pair ( $\mathrm{t}\bar{\mathrm{t}}$ ) production in final states with two charged leptons and multiple jets is presented, based on proton–proton collision data collected by the CMS experiment at the CERN LHC at $\sqrt{s}=13\text{TeV}$ , corresponding to 138 fb⁻¹. The analysis explores the invariant mass of the $\mathrm{t}\bar{\mathrm{t}}$ system and two angular observables that provide direct access to the correlation of top quark and antiquark spins. A significant excess of events is observed near the kinematic $\mathrm{t}\bar{\mathrm{t}}$ threshold compared to the non-resonant production predicted by fixed-order perturbative quantum chromodynamics (pQCD). The observed enhancement is consistent with the production of a color-singlet pseudoscalar ( ${}^1{\text{S}}_0^{\left[1\right]}$ ) quasi-bound toponium state, as predicted by non-relativistic quantum chromodynamics. Using a simplified model for ${}^1{\text{S}}_0^{\left[1\right]}$ toponium, the cross section of the excess above the pQCD prediction is measured to be $8.8{}_{-1.4}^{+1.2}\text{pb}$ . 

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5. Search for Neutrino Emission from Hard X-Ray AGN with IceCube

   https://doi.org/10.3847/1538-4357/ada94b  

   Abbasi, R; Ackermann, M; Adams, J; Agarwalla, S K; Aguilar, J A; Ahlers, M; Alameddine, JM; Amin, N M; Andeen, K; Argüelles, C; et al (March 2025, The Astrophysical Journal)

   Abstract Active galactic nuclei (AGN) are promising candidate sources of high-energy astrophysical neutrinos, since they provide environments rich in matter and photon targets where cosmic-ray interactions may lead to the production of gamma rays and neutrinos. We searched for high-energy neutrino emission from AGN using the Swift-BAT Spectroscopic Survey catalog of hard X-ray sources and 12 yr of IceCube muon track data. First, upon performing a stacked search, no significant emission was found. Second, we searched for neutrinos from a list of 43 candidate sources and found an excess from the direction of two sources, the Seyfert galaxies NGC 1068 and NGC 4151. We observed NGC 1068 at flux ${\varphi }_{{\nu }_{\mu }+{\overline{\nu }}_{\mu }}$ = $4.02_{-1.52}^{+1.58}\times 10^{-11}$ TeV⁻¹cm⁻²s⁻¹normalized at 1 TeV, with a power-law spectral indexγ= 3.10 ${}_{-0.22}^{+0.26}$ , consistent with previous IceCube results. The observation of a neutrino excess from the direction of NGC 4151 is at a posttrial significance of 2.9σ. If interpreted as an astrophysical signal, the excess observed from NGC 4151 corresponds to a flux ${\varphi }_{{\nu }_{\mu }+{\overline{\nu }}_{\mu }}$ = $1.51_{-0.81}^{+0.99}\times 10^{-11}$ TeV⁻¹cm⁻²s⁻¹normalized at 1 TeV andγ= 2.83 ${}_{-0.28}^{+0.35}$ . 

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