WISPIT 1
WISPIT 1 is a young binary star system hosting two giant exoplanets on wide orbits. The system was the first target of the astronomical survey Wide Separation Planets In Time, which observed the system with VLT/SPHERE in the near-infrared range, obtaining direct images of the two circumbinary planets, as well as discovering the binary nature of the star.
Stellar characteristics
WISPIT 1 is a close stellar binary which is only marginally resolved in the observations, with the much fainter secondary visible as a bump on the shape of the merged image of both stars on VLT/SPHERE imagery. The WISPIT survey observations, which were performed on,, and, showed negligible motion of the secondary relative to the primary, which confirms that the secondary is a bound companion and not a background star. To derive the calculation, the shape of the combined stars' image was fitted to a model of two separate sources, which implies a physical projected separation of at least, corresponding to a Keplerian orbit of a period of at least.The age estimation|age] of the system is determined based on the abundance of lithium, which is a crucial indicator of age in pre-main-sequence stars due to the lithium burning process. The evolutionary model of lithium depletion for the primary star corresponds to an age of.
The calculated age is similar also to that of a nearby faint red star. Another nearby star with a similar proper motion is, which also appears to be young based on fast rotation. This implies a common origin of the stars.
Planetary system
The binary star is accompanied by two gas giants on very wide orbits, observed at projected separations of and. Their status as planetary companions rather than background objects is confirmed by a common proper motion during the two years of observations with VLT/SPHERE. The orbital period cannot be determined yet as no orbital motion was detected during the timeframe of available observations.The mass of the two planets can be estimated based on the observed magnitude and colour index in comparison to the theoretical isochrones, assuming that the planets have the same age as the star. The inferred masses are below the deuterium burning limit, confirming their nature as planets rather than brown dwarfs. The planet WISPIT 1b has a colour similar to that of other directly imaged gas giants, and implied mass of. WISPIT 1c is one of the faintest planets imaged in both H and K bands at the time of its discovery. Its mass is most likely in the range of, though van Capelleveen et al. note that different isochrones predict significantly different masses, with the reported mass interpolated between the two models used in the study.