The star is known to host three transiting exoplanets, discovered in 2017 from lightcurves gathered by the Kepler space telescope during the K2 extension mission.
[3][7] K2-136 was identified as a high-proper-motion star during the Luyten Palomar Survey in the 1970s and was included in the Luyten-Palomar proper motion catalogue, where it received the designation LP 358‑348.
[4][3][12] The star, designated as EPIC 247589423 in the K2 input catalog, was observed from 8 March 2017 to 27 May 2017 during Campaign 13, with the calibrated data publicly released on 28 August 2017.
X-ray observations of the star were carried out by XMM-Newton on 11 September 2018, obtaining a good quality spectrum in the 0.2–12.0 keV energy band.
[7] A series of radial velocity measurements was carried out in the course of a planetary mass characterization study by Andrew W. Mayo et al. between 11 August 2018 and 31 October 2020, 93 with HARPS-N and 22 with ESPRESSO.
It is likely a terrestrial planet, though as of 2025[update], no composition is ruled out yet based on the upper limit of mass determined from radial velocity observations.
The calculated density of 3.69+0.67−0.56 g⋅cm−3 is consistent with both a water-dominated ocean world composition and a large Earth-like core and a H/He envelope with a mass fraction of ~5%, or any combination of the non-detection of excess absorption by neutral helium in the spectrum of the starlight recorded by the Subaru Telescope during the transit on 2020.
The planet is likely still experiencing atmospheric escape at a non-negligible rate and may lose the remaining gaseous envelope within 2 billion years.