Search for: All records

Abstract Among Neptunian mass exoplanets (20−50M_⊕), puffy hot Neptunes are extremely rare, and their unique combination of low mass and extended radii implies very low density (ρ< 0.3 g cm⁻³). Over the last decade, only a few puffy planets have been detected and precisely characterized with both transit and radial velocity observations, most notably including WASP-107b, TOI-1420b, and WASP-193b. In this paper, we report the discovery of TOI-1173 Ab, a low-density ( $\rho ={0.195}_{-0.017}^{+0.018}$g cm⁻³) super-Neptune withP= 7.06 days in a nearly circular orbit around the primary G-dwarf star in the wide binary system TOI-1173 A/B. Using radial velocity observations with the MAROON-X and HIRES spectrographs and transit photometry from TESS, we determine a planet mass ofM_p= 27.4 ± 1.7M_⊕and radius ofR_p= 9.19 ± 0.18R_⊕. TOI-1173 Abis the first puffy super-Neptune planet detected in a wide binary system (projected separation ∼11,400 au). We explore several mechanisms to understand the puffy nature of TOI-1173 Aband show that tidal heating is the most promising explanation. Furthermore, we demonstrate that TOI-1173 Ablikely has maintained its orbital stability over time and may have undergone von-Zeipel–Lidov–Kozai migration followed by tidal circularization, given its present-day architecture, with important implications for planet migration theory and induced engulfment into the host star. Further investigation of the atmosphere of TOI-1173 Abwill shed light on the origin of close-in low-density Neptunian planets in field and binary systems, while spin–orbit analyses may elucidate the dynamical evolution of the system. 

We report the confirmation and characterisation of TOI-1820 b, TOI-2025 b, and TOI-2158 b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around 4.9 d, 8.9 d, and 8.6 d for TOI-1820 b, TOI-2025 b, and TOI-2158 b, respectively. The sizes of the planets range from 0.96 to 1.14 Jupiter radii, and their masses are in the range from 0.8 to 4.4 Jupiter masses. For two of the systems, namely TOI-2025 and TOI-2158, we see a long-term trend in the radial velocities, indicating the presence of an outer companion in each of the two systems. For TOI-2025 we furthermore find the star to be well aligned with the orbit, with a projected obliquity of 9 −31 +33 °. As these planets are all found in relatively bright systems ( V ~ 10.9–11.6 mag), they are well suited for further studies, which could help shed light on the formation and migration of hot and warm Jupiters. 

We present the discovery of TOI-1518b -- an ultra-hot Jupiter orbiting a bright star $V = 8.95$. The transiting planet is confirmed using high-resolution optical transmission spectra from EXPRES. It is inflated, with $$R_p = 1.875\pm0.053\,R_{\rm J}$$, and exhibits several interesting properties, including a misaligned orbit ($${240.34^{+0.93}_{-0.98}}$$ degrees) and nearly grazing transit ($$b =0.9036^{+0.0061}_{-0.0053}$$). The planet orbits a fast-rotating F0 host star ($$T_{\mathrm{eff}} \simeq 7300$$ K) in 1.9 days and experiences intense irradiation. Notably, the TESS data show a clear secondary eclipse with a depth of $$364\pm28$$ ppm and a significant phase curve signal, from which we obtain a relative day-night planetary flux difference of roughly 320 ppm and a 5.2$$\sigma$$ detection of ellipsoidal distortion on the host star. Prompted by recent detections of atomic and ionized species in ultra-hot Jupiter atmospheres, we conduct an atmospheric cross-correlation analysis. We detect neutral iron ($${5.2\sigma}$$), at $$K_p = 157^{+68}_{-44}$$ km s$$^{-1}$$ and $$V_{\rm sys} = -16^{+2}_{-4}$$ km s$$^{-1}$$, adding another object to the small sample of highly irradiated gas-giant planets with Fe detections in transmission. Detections so far favor particularly inflated gas giants with radii $$rsim 1.78\,R_{\rm J}$$; although this may be due to observational bias. With an equilibrium temperature of $$T_{\rm eq}=2492\pm38$$ K and a measured dayside brightness temperature of $$3237\pm59$$ K (assuming zero geometric albedo), TOI-1518b is a promising candidate for future emission spectroscopy to probe for a thermal inversion. 

ABSTRACT We present the discovery and characterization of six short-period, transiting giant planets from NASA’s Transiting Exoplanet Survey Satellite (TESS) -- TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), and TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9 <G < 11.8, 7.7 <K < 10.1). Using a combination of time-series photometric and spectroscopic follow-up observations from the TESS Follow-up Observing Program Working Group, we have determined that the planets are Jovian-sized (RP  = 0.99--1.45 RJ), have masses ranging from 0.92 to 5.26 MJ, and orbit F, G, and K stars (4766 ≤ Teff ≤ 7360 K). We detect a significant orbital eccentricity for the three longest-period systems in our sample: TOI-2025 b (P  = 8.872 d, 0.394$$^{+0.035}_{-0.038}$$), TOI-2145 b (P  = 10.261 d, e  = $$0.208^{+0.034}_{-0.047}$$), and TOI-2497 b (P  = 10.656 d, e  = $$0.195^{+0.043}_{-0.040}$$). TOI-2145 b and TOI-2497 b both orbit subgiant host stars (3.8 < log  g <4.0), but these planets show no sign of inflation despite very high levels of irradiation. The lack of inflation may be explained by the high mass of the planets; $$5.26^{+0.38}_{-0.37}$$ MJ (TOI-2145 b) and 4.82 ± 0.41 MJ (TOI-2497 b). These six new discoveries contribute to the larger community effort to use TESS to create a magnitude-complete, self-consistent sample of giant planets with well-determined parameters for future detailed studies. 

Abstract The James Webb Space Telescope will be able to probe the atmospheres and surface properties of hot, terrestrial planets via emission spectroscopy. We identify 18 potentially terrestrial planet candidates detected by the Transiting Exoplanet Survey Satellite (TESS) that would make ideal targets for these observations. These planet candidates cover a broad range of planet radii ( R p ∼ 0.6–2.0 R ⊕ ) and orbit stars of various magnitudes ( K s = 5.78–10.78, V = 8.4–15.69) and effective temperatures ( T eff ∼ 3000–6000 K). We use ground-based observations collected through the TESS Follow-up Observing Program (TFOP) and two vetting tools— DAVE and TRICERATOPS —to assess the reliabilities of these candidates as planets. We validate 13 planets: TOI-206 b, TOI-500 b, TOI-544 b, TOI-833 b, TOI-1075 b, TOI-1411 b, TOI-1442 b, TOI-1693 b, TOI-1860 b, TOI-2260 b, TOI-2411 b, TOI-2427 b, and TOI-2445 b. Seven of these planets (TOI-206 b, TOI-500 b, TOI-1075 b, TOI-1442 b, TOI-2260 b, TOI-2411 b, and TOI-2445 b) are ultra-short-period planets. TOI-1860 is the youngest (133 ± 26 Myr) solar twin with a known planet to date. TOI-2260 is a young (321 ± 96 Myr) G dwarf that is among the most metal-rich ([Fe/H] = 0.22 ± 0.06 dex) stars to host an ultra-short-period planet. With an estimated equilibrium temperature of ∼2600 K, TOI-2260 b is also the fourth hottest known planet with R p < 2 R ⊕ .