The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

  title={The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation},
  author={Shreyas Vissapragada and Heather A. Knutson and Michael Greklek-McKeon and Antonija Oklop{\vc}i{\'c} and Fei Dai and Leonardo A. dos Santos and Nemanja Jovanovic and Dimitri Mawet and Maxwell A. Millar-Blanchaer and Kimberly Paragas and Jessica J. Spake and Samaporn Tinyanont and Gautam Vasisht},
  journal={The Astronomical Journal},
Transit surveys indicate that there is a deficit of Neptune-sized planets on close-in orbits. If this “Neptune desert” is entirely cleared out by atmospheric mass loss, then planets at its upper edge should only be marginally stable against photoevaporation, exhibiting strong outflow signatures in tracers like the metastable helium triplet. We test this hypothesis by carrying out a 12-night photometric survey of the metastable helium feature with Palomar/WIRC, targeting seven gas-giant planets… 


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