A stellar occultation by Vanth, a satellite of (90482) Orcus

•This is the first recorded multi-chord stellar occultation by Orcus’ satellite Vanth.•For a spherical Vanth, the diameter is constrained to 443 ± 10 km.•A 3-σ upper limit of ∼4 μbar is found for a global Vanth atmosphere.•No rings or surrounding material were detected around Vanth and to a closest approach distance of ∼5040 km from Orcus.