A newly identified candidate exoplanet, known as HD 137010 b, has scientists buzzing with excitement. This planet may bear some resemblance to Earth, but it has one striking difference: it could be even colder than Mars, which is already a frozen world. The discovery comes from ongoing analysis of data collected by NASA’s Kepler Space Telescope, which was retired in 2018 but continues to yield fascinating insights into the cosmos.

An artist's concept animation of exoplanet candidate HD 137010 b, which gives a view as if flying above this possible rocky planet slightly larger than Earth, thought to orbit a Sun-like star about 146 light-years away. This view also creates an effect similar to a transit, as the planet's star disappears and then reappears from behind HD 137010 b.NASA/JPL-Caltech/Keith Miller (Caltech/IPAC)

What Makes HD 137010 b Unique?

Located approximately 146 light-years away, HD 137010 b is a rocky planet slightly larger than our own. It orbits a star similar to our Sun, but with some key differences that could affect its climate. The planet's orbital period is estimated to be around one Earth year, placing it within the outer edge of its star's habitable zone, where conditions might allow for liquid water if the atmosphere is just right.

Understanding Exoplanets

Exoplanets, or planets that orbit stars outside our solar system, are a major focus of astronomical research. HD 137010 b stands out as a potential candidate for further study because it crosses in front of its star from our perspective, an event known as a transit. This allows scientists to gather more data and possibly confirm its existence as a true planet.

The Cold Reality

However, there’s a catch. The star that HD 137010 b orbits is cooler and dimmer than our Sun, meaning the planet receives less than a third of the sunlight that Earth does. This could result in surface temperatures plummeting to around minus 90 degrees Fahrenheit (minus 68 degrees Celsius). To put that in perspective, Mars has an average temperature of about minus 85 degrees Fahrenheit (minus 65 degrees Celsius).

Confirming the Discovery

Currently, HD 137010 b is still classified as a candidate planet and requires further observations to be confirmed. The discovery was made using a single transit event detected during Kepler’s second mission, known as K2. During this event, scientists observed the planet crossing in front of its star, blocking its light for about 10 hours, which is shorter than Earth's transit time.

The Challenge of Observation

Capturing additional transits of HD 137010 b will be challenging due to its orbital distance, which is similar to Earth's. This means that transits occur less frequently compared to planets that orbit their stars more closely. To confirm its status as a planet, astronomers will need to observe multiple transits, a task that may be aided by NASA’s TESS (Transiting Exoplanet Survey Satellite) or the European Space Agency’s CHEOPS (CHaracterising ExOPlanets Satellite).

Potential for Habitability

Despite the cold conditions, researchers believe that HD 137010 b could still potentially host a temperate or even watery environment. This would depend on the composition of its atmosphere, particularly if it has a higher concentration of carbon dioxide than Earth. The study suggests there’s a 40% chance that the planet lies within the 'conservative' habitable zone and a 51% chance of being in the broader 'optimistic' habitable zone.

The Research Team

The findings about HD 137010 b were published in a paper titled 'A Cool Earth-sized Planet Candidate Transiting a Tenth Magnitude K-dwarf From K2' in The Astrophysical Journal Letters. The research was led by Alexander Venner, a Ph.D. student from the University of Southern Queensland, Australia, who is now a postdoctoral researcher at the Max Planck Institute for Astronomy in Germany. The team also included volunteers from NASA’s Planet Hunters citizen science project.

Looking Ahead

As we look to the future, the quest to confirm HD 137010 b and understand its characteristics is just beginning. With advanced telescopes and ongoing missions, astronomers are eager to gather more data that could reveal the true nature of this intriguing candidate planet. The potential for discovering new worlds similar to our own keeps the excitement alive in the field of exoplanet research.

The Role of Citizen Science

Citizen science projects like Planet Hunters play a vital role in the discovery of exoplanets. By allowing enthusiasts and volunteers to analyze data, these projects expand the reach of scientific research. The contributions from these dedicated individuals have led to significant findings, including the identification of HD 137010 b.