Ilaria Carleo; Amadeo Castro-Gonz谩lez; Enric Pall茅; Felipe Murgas; Grzegorz Nowak; Gaia Lacedelli; Thomas Masseron; Emily W. Wong; Patrick Eggenberger; Vincent Bourrier; Dawid Jankowski; Krzysztof Go藕dziewski; Douglas R. Alves; James S. Jenkins; Sergio Messina; Keivan G. Stassun; Jose I. Vines; Matteo Brogi; David R. Ciardi; Catherine A. Clark; William Cochran; Karen A. Collins; Hans J. Deeg; Elise Furlan; Davide Gandolfi; Samuel Gerald铆a Gonz谩lez; Artie P. Hatzes; Coel Hellier; Steve B. Howell; Judith Korth; Jorge Lillo-Box; John H. Livingston; Jaume Orell-Miquel; Carina M. Persson; Seth Redfield; Boris Safonov; David Baker; Rafael Delfin Barrena Delgado; Allyson Bieryla; Andrew Boyle; Pau Bosch-Cabot; N煤ria Casasayas Barris; Stavros Chairetas; Jerome P. De Leon; Izuru Fukuda; Akihiko Fukui; Pere Guerra; Kai Ikuta; Kiyoe Kawauchi; Emil Knudstrup; Florence Libotte; Michael B. Lund; Rafael Luque; Eduardo Lorenzo Mart铆n Guerrero De Escalante; Bob Massey; Edward J. Michaels; Giuseppe Morello; Norio Narita; Hannu Parvianien; Richard P. Schwarz; Avi Shporer; Monika Stangret; Noriharu Watanabe; Cristilyn N. Watkins (2026).听.听Astronomy & Astrophysics, 707, A4.听
This study focuses on a rare type of exoplanet found very close to its star, in a region known as the听鈥渉ot Neptune desert.鈥�听This term refers to an area in the relationship between a planet鈥檚 size and its orbital period where planets of a certain size (like Neptune) are unexpectedly scarce. Scientists think this is because intense heat from the nearby star can strip away a planet鈥檚 atmosphere (atmospheric loss) or because such planets migrate inward in ways that make them unstable. Studying planets that do exist in this region can help explain how planets form and survive under extreme conditions.
The researchers investigated a candidate planet discovered by NASA鈥檚 TESS mission, called TOI-3862 b. They confirmed that it is indeed a planet by combining two methods:听transits听(measuring dips in starlight when the planet passes in front of its star) and听radial velocity听(tracking tiny wobbles in the star caused by the planet鈥檚 gravity). Using these techniques, they determined that TOI-3862 b is a 鈥渟uper-Neptune,鈥� meaning it is larger and more massive than Neptune but smaller than gas giants like Jupiter. It orbits its star extremely quickly鈥攐nce every 1.56 days鈥攁nd has a relatively high density, suggesting it may have a substantial core or has lost part of its atmosphere.
Because TOI-3862 b lies deep within the hot Neptune desert, where few such planets are found, it provides an important case for testing theories about how planets evolve in harsh environments. Its existence suggests that, under certain conditions, planets can resist atmospheric loss or follow unusual evolutionary paths that allow them to survive where most others do not.
Fig. 1 – 听Left: TESS TPF of Sector 22 for TOI-3862. The color bar represents the electron counts for each pixel. The orange squares denote the pixels chosen by the TESS pipeline for aperture photometry. All sources from Gaia DR3 are overlaid on the plot and depicted as circles of varying sizes, corresponding to their G-mag difference relative to the target (as detailed in the legend). This visualization was generated using the听tpfplotter听code (). Gray arrows indicate the proper motion directions for all sources shown in the plot.听Right: TESS heat maps, generated through听TESS-cont听(), showing the percentage of the flux in each pixel that comes from the target star. The five most contaminating Gaia DR3 sources are overlaid with sizes scaling with their emitted fluxes.