Caption: An artist’s impression showcasing the potential evolution of exoplanet LP 890-9c, from a scorching Earth-like world to a desiccated Venus-like environment. Credit: Carl Sagan Institute/R. Payne
How close can a rocky planet orbit a star and still sustain water and life? A recently discovered exoplanet holds the key to unraveling this profound enigma.
Dubbed “Super-Earth” LP 890-9c, or SPECULOOS-2c, this celestial body is proving to be a valuable source of insights into the conditions prevailing at the inner boundary of a star’s habitable zone, thereby shedding light on the divergent evolutionary paths taken by Earth and Venus. Spearheading this groundbreaking research is Lisa Kaltenegger, an associate professor of astronomy at Cornell University.
Kaltenegger’s team stumbled upon LP 890-9c, which resides in close proximity to the inner edge of its solar system’s habitable zone. Depending on whether this planet still possesses warm oceans, a steam-laden atmosphere, or has lost its water altogether (assuming it once harbored oceans akin to those on Earth), its appearance would starkly vary.
“The study of this planet will unravel the mysteries of the inner edge of the habitable zone—how long can a rocky planet maintain habitability as it experiences rising temperatures,” Kaltenegger explained. “It will provide fundamental insights into the evolution of rocky planets subjected to increasing stellar radiation, and offer glimpses into our own future and that of Earth.”
Kaltenegger serves as the lead author of the paper titled “Hot Earth or Young Venus? A Nearby Transiting Rocky Planet Mystery,” published in the Monthly Notices of the Royal Astronomical Society: Letters.
LP 890-9c, one of two super-Earths orbiting a red dwarf star located 100 light years away from Earth, was announced by researchers last year. (NASA’s Transiting Exoplanet Survey Satellite had previously identified LP 890-9b.) LP 890-9c, which is approximately 40% larger than Earth, completes its orbit around the small, cool star in just 8.5 days, offering the possibility of liquid water or an atmosphere rich in water vapor.
These characteristics render it one of the most compelling targets for the James Webb Space Telescope (JWST) to study, alongside the renowned TRAPPIST-1 system.
The team’s models represent the first comprehensive depiction of the distinct chemical signatures exhibited by rocky planets near the interior boundary of the habitable zone. Variables considered in these calculations include the planet’s size, mass, chemical composition, surface temperature and pressure, atmospheric height, and cloud cover. Such estimations are crucial in determining the time required by the JWST to confirm the primary constituents of an atmosphere, if present.
The models encompass various scenarios reflecting different stages in the evolution of rocky planets. These scenarios range from a “hot Earth” where the conditions for life might still exist, to a desolate Venus-like world characterized by a carbon dioxide atmosphere. Intermediate phases depict what Earth is projected to experience as the Sun progressively intensifies and heats up over time, leading to the gradual evaporation of the oceans and the eventual saturation of the atmosphere with steam before complete depletion.
The duration of these processes remains uncertain, and the astronomers emphasize that LP 890-9c offers a rare opportunity to explore and fathom this evolutionary journey.
“This planet represents our first testing ground for these diverse scenarios,” Kaltenegger stated. “If it still resembles a hotter Earth—hot, yet with liquid water and conditions suitable for life—then the timeline is more protracted than we initially surmised. However, if we find it to be a fully realized Venus, it would imply rapid water loss.”
It is plausible that LP 890-9c lacks an atmosphere and does not support life, or it may bear resemblance to Venus, featuring thick clouds that hinder the reflection of light and provide limited information. Further investigations hold the promise of unraveling valuable clues, according to Kaltenegger.
“Given our lack of knowledge about this planet residing at the brink of habitability, we must embark on this scientific endeavor,” she expressed. “This is the true essence of genuine exploration.”
Reference: “Hot Earth or Young Venus? A nearby transiting rocky planet mystery” by L. Kaltenegger, R. C. Payne, Z. Lin, J. Kasting, and L. Delrez, 21 June 2023, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnrasl/slad064
Table of Contents
Frequently Asked Questions (FAQs) about Exoplanet
What is LP 890-9c and why is it significant?
LP 890-9c, also known as SPECULOOS-2c, is a “Super-Earth” exoplanet that orbits close to the inner edge of its solar system’s habitable zone. It holds significance because it provides valuable insights into the conditions at the inner boundary of a star’s habitable zone and helps explain the contrasting development of Earth and Venus. Studying LP 890-9c can shed light on how long a rocky planet can maintain habitability as it gets hotter, providing fundamental knowledge about the evolution of rocky planets and offering glimpses into the future of our own planet.
How does LP 890-9c differ depending on its water content?
LP 890-9c’s appearance would vastly differ depending on whether it still has warm oceans, a steam atmosphere, or if it has lost its water altogether. If it retains liquid water and conditions suitable for life, it would resemble a hotter version of Earth. However, if it has lost its water, it would resemble a desolate Venus-like world with a carbon dioxide atmosphere. Understanding these different scenarios helps us estimate the timelines and processes involved in a rocky planet’s evolution.
What role does the James Webb Space Telescope (JWST) play in studying LP 890-9c?
LP 890-9c is considered one of the best targets for the JWST to study among the known potentially habitable terrestrial planets. The telescope will help confirm the basic composition of LP 890-9c’s atmosphere, if it has one. By analyzing the chemical signatures and atmospheric constituents, the JWST will provide valuable data to further understand the planet’s habitability and evolution.
How does LP 890-9c contribute to our understanding of habitable zones and rocky planet evolution?
LP 890-9c, residing near the inner boundary of its star’s habitable zone, offers a unique opportunity to explore the conditions and evolution of rocky planets within such zones. By studying LP 890-9c, scientists can gain insights into how rocky planets evolve with increasing starlight and how habitability is maintained or lost over time. This knowledge enhances our understanding of habitable zones and provides valuable information about the potential fate of Earth and other rocky planets as their host stars age.
More about Exoplanet
- Monthly Notices of the Royal Astronomical Society: Letters – Hot Earth or Young Venus? A nearby transiting rocky planet mystery
- NASA’s Transiting Exoplanet Survey Satellite (TESS) – LP 890-9b
- James Webb Space Telescope (JWST) – Official Website
- Cornell University Department of Astronomy – Lisa Kaltenegger
- Carl Sagan Institute – Official Website
3 comments
lp 890-9c sounds cool! it’s like a mini earth or a venus. wonder what it really looks like. gotta keep exploring, u know?
this is the stuff that blows my mind! lp 890-9c, jwst, habitable zones – so much to learn. excited to see what we discover about exoplanets and our place in the universe! #astronomyrocks
super interesting article! never knew about exoplanets like LP 890-9c. its amazing how it could teach us abt habitability and rocky planets. can’t wait for more research on it!