2026-03-27 マックス・プランク研究所
These images, taken with ESO’s Very Large Telescope (VLT) shows a planetary system being born around the young star WISPIT 2. The star is surrounded by a disc of gas and dust –– the raw material out of which planets form and grow. In 2025 a team of astronomers detected a young planet, called WISPIT 2b, carving out a gap in the disc around the star. Now the same team has confirmed the presence of a second planet, WISPIT 2c, orbiting even closer to the star, as shown in the inset. © ESO/C. Lawlor, R. F. van Capelleveen et al.
＜関連情報＞
若い埋没原始惑星WISPIT 2cの直接分光観測による確認 Direct spectroscopic confirmation of the young embedded proto-planet WISPIT 2c
Chloe Lawlor, Richelle F. van Capelleveen, Guillaume Bourdarot, Christian Ginski, Matthew A. Kenworthy, Tomas Stolker, Laird Close, Alexander J. Bohn, Frank Eisenhauer, Paulo Garcia, Sebastian F. Hönig, Jens Kammerer, Laura Kreidberg, Sylvestre Lacour, Jean-Baptiste Le Bouquin, Eric Mamajek, Mathias Nowak, Thibaut Paumard, Christian Straubmeier, Nienke van der Marel, the exoGRAVITY Collaboration
arXiv Submitted on 23 Mar 2026
DOI:https://doi.org/10.48550/arXiv.2603.22085
Abstract
WISPIT 2 is a nearby young star with a multi-ringed disk which was recently confirmed to host a ~4.9 MJup gas giant planet embedded in a large (60 au) gap at a radial separation of 57 au from the host star. We confirm and characterise a second, close-in planet in the WISPIT 2 system using a combination of new VLT/SPHERE H-band dual-polarisation imaging and VLTI/GRAVITY K-band interferometric observations of the WISPIT 2 system. The GRAVITY detection is consistent with a point-like source while its extracted K-band spectrum shows CO band-head absorption at 2.3 microns and a continuum shape consistent with a young giant planet. From the GRAVITY data we extract a medium resolution K-band spectrum of the companion and fit atmospheric model grids using the species tool with nested sampling to constrain its effective temperature, radius, and luminosity. We infer Teff of 1500-2600 K, a radius of 0.91-2.2 RJup, and a luminosity of (-3.47)-(-3.63). Comparison with evolutionary tracks implies a mass range of 8-12 MJup, approximately twice as massive as the previously confirmed WISPIT 2b. The astrometry rules out a background source and marginally detects orbital motion of WISPIT 2c, which needs further follow-up observations for confirmation. WISPIT 2 now becomes an analogue to PDS 70, offering a second laboratory for studying the formation and early evolution of a multi-planet system within its natal disk.
