Wide Separation Planets in Time (WISPIT): Discovery of a Gap Hα Protoplanet WISPIT 2b with MagAO-X

Abstract Excellent ( . ° 21 ± 0 . ° 41) likely clearing a dust-free gap between the two brightest dust rings in the transitional disk. Our signal-to-noise ratio of 12.5 detection gave an H α ASDI contrast of (6.5 ± 0.5) × 10 −4 and an H α line flux of (1.29 ± 0.28) × 10 −15 erg s −1 cm −2 . We also present L ′ photometry from LBT/LMIRcam of the planet ( L ′ = 15.30 ± 0.05 mag), which, when coupled with an age of 5 . 1 − 1 . 3 + 2 . 4 Myr, yields a planet mass estimate of 5.3 ± 1.0 M jup from the DUSTY evolutionary models. WISPIT 2b is accreting at 2 . 25 − 0 . 17 + 3 . 75 × 10 −12 M Sun yr −1 . WISPIT 2b is very similar to the other H α protoplanets in terms of mass, age, flux, and accretion rate. The inclination of the system ( i = 44°) is also, surprisingly, very similar to the other known H α protoplanet systems, which all cluster from 37° ≤ i ≤ 52°. We argue this clustering has only a ∼1.0% (2.6 σ ) probability of occurring randomly, and so we speculate that magnetospherical accretion might have a preferred inclination range (∼37°–52°) for the direct (cloud free, low extinction) line of sight to the H α line formation/shock region. We also find at 110 mas (∼15 au deprojected) a close companion candidate (CC1) that may be consistent with an inner dusty 9 ± 4 M jup planet.