جيمس ويب يصطاد كوكبًا خفيًا من قرص الغبار سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2606.23789

We report the discovery of $$\beta$$ Pictoris d ($$\beta$$ Pic d), a third giant planet in the $$\beta$$ Pictoris system, which now becomes only the second directly imaged system with more than two confirmed planets. $$\beta$$ Pic d was serendipitously detected in JWST/NIRSpec IFU observations. A second epoch of NIRSpec and MIRI/MRS observations confirm the initial discovery. The extracted spectrum shows clear CH$$_4$$, CO, and H$$_2$$O absorption features, and $$\beta$$ Pic d's measured radial velocity is consistent with its orbital position. Radial velocity and astrometry measurements combined with orbital stability simulations suggest a semi-major axis $$>$$30 au, consistent with $$\beta$$ Pic d being responsible for carving the inner edge of the $$\beta$$ Pictoris debris disk. Using effective temperature estimates from atmosphere model grid fits combined with evolutionary models, we estimate a mass of 2--4 $$M_\mathrm{Jup}$$. $$\beta$$ Pic d is the first planet discovered using spectral template matching with moderate-resolution spectroscopy, highlighting its sensitivity to planetary molecular features hidden within bright extrasolar debris disks that are difficult to access with broadband imaging.