عملاق كوكبي أم عالم مزدوج؟ سريع

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2604.23448

Epsilon Indi A b is a directly imaged $$\sim6 M_{\rm Jup}$$ exoplanet orbiting a nearby (3.6 pc) K-dwarf at $$\sim 30$$ AU. We analyze archival JWST/MIRI 15 $$\mu$$m coronagraphic imaging of this planet to search for directly imaged satellites orbiting Eps Ind A b. Within the planet's Hill sphere (radius $$R_H \approx 2.3$$ AU or $$1.3 \lambda/D$$), we compare single- and double-PSF models using Bayesian evidence. We find that a double-PSF (binary planet) fit is preferred. This apparent preference can most plausibly be explained by systematics, although follow-up observations would be required to fully rule out a binary planet interpretation. We construct a contrast curve of the exoplanet after removing this feature, demonstrating sensitivity to companions as faint as $$0.03\times$$ the F1550C flux of Eps Ind A b (equivalent to $$T = 130$$ K, $$1.3 M_{\rm Jup}$$) at large separations (>2 AU). We also demonstrate sensitivity to brighter companions $$0.2\times$$ the F1550C flux of Eps Ind A b (equivalent to $$T = 180$$ K, $$2.5 M_{\rm Jup}$$) down to separations of 0.52 AU (1.3 pixels; $$0.29 \lambda/D$$; 144 mas). This study demonstrates that JWST/MIRI can directly detect exomoons or binary planets inside the Hill sphere of directly imaged exoplanets orbiting neighboring stars.