Thermal observations of MUSES-C mission target (25143) 1998 SF$_\mathsf{36}$

We present thermal observations of MUSES-C mission target, (25143) 1998 SF 36 . The mid-IR radiation in the N -band (11.9 μ m) was measured using the ESO 3.6 m telescope with TIMMI2. Assuming the Standard Thermal Model and combining the thermal flux in the N -band with the time-resolved absolute magnitude in optical, the derived diameter and the geometric albedo are 0.35 ( ± 0.03) km and 0.23 (+0.07, -0.05), respectively. While these values are model-dependent, we conclude that this Apollo class asteroid is of small size and its albedo is consistent with spectroscopic classification as an S-type asteroid.