The discovery of two Earth- alien worlds has given scientists another exciting reason to keep searching for planets beyond our Solar System that could potentially support life. Both planets were found orbiting a star called GJ 1002 and their masses are similar to that of Earth.
What makes the discovery particularly interesting is that both planets are located within the stars zone, the region around a star where temperatures may be suitable for liquid water to exist on a planets surface.
A Tiny Star With Two Interesting Planets
GJ 1002 is a cool star classified as an M dwarf, a type of star that is much smaller and dimmer than our Sun. The star has around one-eighth of the Suns mass making it considerably less powerful than the star at the center of our Solar System.
Despite its size GJ 1002 is now attracting considerable attention because it hosts two planets that could provide astronomers with valuable opportunities to study potentially habitable worlds.
The planets are known as GJ 1002b and GJ 1002c.
What Does the Habitable Zone Mean?
The term " zone" does not mean that a planet definitely has life. Instead it describes the region around a star where conditions could potentially allow liquid water to remain on a planets surface.
Water is considered one of the important ingredients for life as we know it. However being in the zone alone does not guarantee that a planet has oceans, a suitable atmosphere or living organisms.
Scientists still need more evidence before they can determine what conditions actually exist on GJ 1002b and GJ 1002c.
The Two Planets Have Surprisingly Years
The two planets orbit their small star much faster than Earth orbits the Sun.
GJ 1002b, the planet closer to its star completes one orbit in 10 days. The distant GJ 1002c takes approximately 20 days to complete its journey around GJ 1002.
Although these orbital periods are extremely short compared with Earths 365-day year the star itself is much cooler and dimmer than the Sun. This means a planet can orbit closer to an M dwarf and still potentially receive an amount of energy that makes its location interesting from a habitability perspective.
One of the Closest Systems of Its Kind
Another aspect of the discovery is the systems distance from Earth.
GJ 1002 is about 16 light-years away which is relatively close on the astronomical scale. For comparison NASAs TOI 700 system, which also contains an Earth- planet in the habitable zone is more than 100 light-years away.
The short distance to GJ 1002 gives astronomers an important advantage. Future generations of telescopes may be able to examine these planets in greater detail.
Scientists Still Don't Know If There Is Water
At this stage researchers cannot confirm that either planet has water.
They also do not yet know whether GJ 1002b or GJ 1002c possesses an atmosphere of protecting the surface and creating conditions suitable for life.
Those questions will require observations. Scientists are particularly interested in studying the planets atmospheres and looking for signatures that could reveal what these distant worlds are made of.
How Were the Planets Discovered?
The discovery was made by researchers associated with the Instituto de Astrofísica de Canarias (IAC) in Spain using observations from two instruments: ESPRESSO and CARMENES.
These instruments allow astronomers to detect small changes in a stars motion caused by planets orbiting around it. By measuring these movements researchers can determine that planets are present and estimate important properties such as their masses and orbital periods.
Why M Dwarf Stars Matter
M dwarfs are particularly interesting in the search for habitable planets because they are extremely common throughout the galaxy.
They are much smaller and cooler than stars like the Sun meaning their habitable zones are located closer to the star. This makes planets in those regions easier to detect in some circumstances.
However M dwarfs can also produce stellar activity and radiation which could affect the atmospheres of nearby planets. Understanding whether these worlds can retain atmospheres is therefore an important part of future research.
The James Webb Space Telescope Could Help
The discovery also adds to the growing list of worlds that could eventually be studied with powerful space telescopes.
The James Webb Space Telescope has already transformed the study of exoplanet atmospheres by allowing astronomers to investigate the light passing through or being emitted by planetary atmospheres.
GJ 1002b and GJ 1002c could become targets for future observations. By studying the heat they emit and the light they reflect or transmit through their atmospheres scientists may be able to learn more about their composition and environmental conditions.
Could These Worlds Support Alien Life?
For now there is no evidence that either planet contains life.
Scientists are simply interested in whether the planets have the conditions that could make life possible. The presence of a suitable temperature range is only one piece of a much larger puzzle.
Researchers will need to determine whether these worlds have atmospheres, water and the chemical and environmental conditions before they can seriously assess their habitability.
A Fascinating Step in the Search for Another Earth
The discovery of GJ 1002b and GJ 1002c shows how quickly the search for habitable planets is advancing.
A few decades ago scientists had confirmed very few planets outside our Solar System. Today thousands of exoplanets are. Astronomers are increasingly able to identify worlds that resemble Earth in size and may exist in regions where liquid water could be possible.
At 16 light-years away the GJ 1002 system is close enough to make it particularly exciting. Future observations may reveal whether these two mysterious worlds are simply Earth- planets orbiting a nearby star. Or whether they possess atmospheres and environments that make them even more extraordinary.
For now the answers remain hidden.. As telescope
technology continues to improve astronomers are getting closer, to studying
distant worlds in unprecedented detail. And perhaps one day discovering a
planet that truly resembles our own.
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