Nautilus array to track missing exoplanet atmospheres

Exoplanet atmospheres have become prime targets for astrobiologists in the search for life beyond Earth. This is because exoplanet surfaces can’t be directly imaged yet, so astronomers must get creative in how they search for signs of life, also called biosignatures. Presently, powerful ground- and space-based telescopes like the Atacama Large Millimeter Array (ALMA) and NASA’s James Webb Space Telescope (JWST) are improving in their ability to observe and analyze exoplanet atmospheres. But how did these atmospheres form and evolve, and what could this mean for the search for life beyond Earth?

Now, a team of researchers from the United States and United Kingdom is discussing a new method for studying the evolution of exoplanet atmospheres. Through a white paper draft posted on the arXiv preprint server, the researchers propose the mission concept Nautilus Space Observatory, also called the Nautilus Deep Space Observatory (NDSO), which they suggest could revolutionize not only how exoplanets are studied but also how space telescopes operate in the future. For the purposes of this specific white paper, the researchers opted to focus on exoplanet and exoplanetary atmosphere formation and evolution.

The proposed Nautilus Space Observatory will consist of a constellation of space telescopes whose design and deployment are meant to be both fast and simple while having large enough diameters to conduct groundbreaking science. The white paper discusses several scientific objectives that could be accomplished by Nautilus, including better understanding the timescales for exoplanets evolving into sub-Neptunes and super-Earths.

Super-Earths and sub-Neptunes are the most common exoplanet types, with scientists estimating that 30% to 50% of sun-like stars have at least one of these exoplanet types orbiting them. Other scientific objectives include studying timescales of atmospheric mass loss, carbon-oxygen ratio, and when helium-dominated exoplanets evolve. Timescales range from those of a protoplanetary disk between 0 and 10 million years old to as far as 4.6 billion years, when planets are fully mature.

The white paper notes: “Answering these questions requires the high spatial resolution, broad-wavelength coverage, large effective area, and parallelized multiple units that Nautilus provides. By isolating the physical processes that govern the evolution of planets and their atmospheres, these science objectives directly support NASA’s Cosmic Origins and Exoplanet Exploration Programs.”

Led by the University of Arizona and proposed in the late 2010s, Nautilus is slated to consist of 35 space telescopes with a total lens size and diameter of 14 meters (46 feet) and 8.5 meters (28 feet). These lenses will guide the optics of Nautilus, which could improve observations because current ground- and space-based telescopes use mirrors to collect light for their observations.

The total light-collecting power of Nautilus is more than double that of JWST, more than 10 times that of the Hubble Space Telescope and almost 100 times that of the proposed European Space Agency’s Ariel telescope. Along with the 8.5-meter lens, each Nautilus unit will consist of an instrument package, solar panel and a Mylar balloon.

As noted, this white paper supports NASA’s Cosmic Origins and Exoplanet Exploration Programs, which are two separate programs. Cosmic Origins is meant to better understand the origins of the universe, and the Exoplanet Exploration Program is the primary driver for studying exoplanets, their systems, and their formation and evolution, including their atmospheres.

This white paper also comes as the number of NASA-confirmed exoplanets is just shy of 6,300, with just under 2,200 being Neptune-like (sub-Neptunes) and just over 1,800 being super-Earths. Like most white papers, next steps include turning a concept into reality, with current prototypes being much smaller than the desired 8.5-meter lens.

Who’s behind this story?

Lisa Lock

BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021.

Full profile →

Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

Full profile →