New exoplanets and what we learn about them: discoveries, atmospheres and habitability, from JWST and the surveys.
This issue is led by a Hubble archive result pointing to a possible second-generation planet around a white dwarf. It also covers a tentative magnetic-field signal on KELT-9b that did not repeat, a 29-planet TESS giant-planet catalogue, and new work on atmospheric loss and JWST retrievals.
A Nature Astronomy study of Hubble archive data finds an unusual chemical signature in the white dwarf HS 0209+0832. The authors read it as a sign that the star may host a second-generation planet, one formed from material cast off by the star.
SPH simulations show that lower-mass atmospheres are easier to remove in giant impacts, and the authors derive a new scaling law for the loss. Applied to solar system formation, it implies substantial loss for planets below about 0.6 Earth masses. For a roughly 100 bar pre-impact atmosphere, Earth could have lost 20-80% in the Moon-forming impact.
SPIRou observations of KELT-9b show a possible Zeeman Stokes V signature in one 2025 transit (V/I_c = 9.3e-5, false-alarm probability 1.9e-4). Two 2026 transits of comparable sensitivity show nothing at that location, so the authors call it a marginal detection at best.
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Launch dates, scrubs, landings and contract awards from SpaceX, Rocket Lab, Blue Origin and ULA.