Imaging low-mass planets within the habitable zone of α Centauri

Area of Science:

• Astronomy
• Exoplanetary Science
• Astrophysics

Background:

• Direct imaging of exoplanets is challenging, especially for lower-mass planets.
• Mitigating thermal background in mid-infrared observations is crucial for detecting faint planetary signals.
• The closest stellar system, Alpha Centauri, is a prime target for exoplanet searches.

Purpose of the Study:

• To develop and demonstrate a ground-based mid-infrared observing approach for imaging low-mass temperate exoplanets.
• To achieve unprecedented sensitivity in detecting exoplanets around nearby stars, specifically within the Alpha Centauri system.
• To assess the feasibility of imaging rocky, habitable-zone exoplanets with current and future telescope technology.

Main Methods:

• Utilized a novel ground-based mid-infrared observing strategy.
• Analyzed a significant portion (75-80%) of 100 hours of cumulative high-quality observational data.
• Focused on mitigating thermal background noise to enhance detection sensitivity.

Main Results:

• Demonstrated sensitivity to warm sub-Neptune-sized planets across a substantial part of the habitable zone of Alpha Centauri A.
• Achieved an order of magnitude improvement in sensitivity compared to existing state-of-the-art exoplanet imaging mass detection limits.
• Identified a potential candidate signal around Alpha Centauri A, possibly an exoplanet or exozodiacal disk, though an instrumental artifact cannot be excluded.

Conclusions:

• The developed mid-infrared observing approach is highly effective for imaging low-mass exoplanets around nearby stars.
• This technique significantly advances the capability to detect potentially habitable exoplanets, including rocky ones.
• The study paves the way for future direct imaging of Earth-like planets in the habitable zones of nearby stars.