Direct Imaging of Protoplanet HD 169142 b

We present the re-detection of a compact source in the face-on protoplanetary disc surrounding HD 169142, using VLT/SPHERE data in YJH bands. The source is found at a separation of 0.319 (~37 au) from the star. Four lines of evidence argue in favour of the signal tracing a protoplanet: (i) it is found in the annular gap separating the two bright rings of the disc, as predicted by theory; (ii) it is moving at the expected Keplerian velocity for an object at ~37 au across three epochs; (iii) a spiral-shaped signal is present whose morphology is consistent with the expected outer spiral wake triggered by a planet in the gap, and iv) compact ¹²CO and ¹³CO emission was found near the planet, alongside SO and SiS emission suggesting the planet is driving strong stocks to produce gas-phase SiS. The YJH colours we extracted for the object are consistent with tracing scattered starlight, suggesting that the protoplanet is enshrouded in a significant amount of dust, as expected for a circumplanetary disc or envelope surrounding a gap-clearing Jovian-mass protoplanet.