Keith Cowing

1 week ago | astrobiology.com | Keith Cowing

The Milky Way appears beyond Earth’s horizon in this celestial photograph captured by NASA astronaut Don Pettit using a camera with low light and long duration settings pointed out a window on the SpaceX Dragon crew spacecraft. The International Space Station was orbiting 263 miles above the Pacific Ocean just before sunrise. Astrobiology, exoplanet,

1 week ago | astrobiology.com | Keith Cowing

Ly-α observations provide a powerful probe of stellar activity and atmospheric escape in exoplanetary systems. We present here an analysis of 104 HST/STIS orbits monitoring the TRAPPIST-1 system between 2017 and 2022, covering 3–5 transits for each of its seven planets.

1 week ago | astrobiology.com | Keith Cowing

Hycean planets — exoplanets with substantial water ice layers, deep surface oceans, and hydrogen-rich atmospheres — are thought to be favorable environments for life. Due to a relative paucity of atmospheric greenhouse gases, hycean planets have been thought to have wider habitable zones than Earth-like planets, extending down to a few times 0.001 au for those orbiting M dwarfs. In this Letter, we reconsider the hycean habitable zone accounting for star-planet tidal interaction.

1 week ago | astrobiology.com | Keith Cowing

Here we analyse the archival data for a set of 27 Transiting Exoplanet Survey Satellite (TESS) Targets of Interest (TOIs) in search for artificially generated radio signals, or ‘technosignatures’, interrupted by occultation. Exoplanetary eclipses are notable events to observe in the search for technosignatures, as they mark the geometrical alignment of the target, its host star, and Earth.

1 week ago | astrobiology.com | Keith Cowing

The creep tide theory is used to explore several aspects of the tidal evolution of the planetary system of the M-star LP 791-18. We discuss the early synchronization of the exo-Earth LP 791-18d and show that the trapping of its rotation in a 3:2 spin-orbit resonance would only have been possible if its eccentricity were approximately 0.04 or larger. The planet is likely in synchronous rotation.