Indian Institute of Science (IISc) astronomers have discovered a new method for studying the atmospheres of extrasolar planets that they hope to apply to Earth. There have been approximately 5,000 of these exoplanets found orbiting them, similar to our solar system. According to the research, the polarization of light can be used to study planets orbiting stars other than the Sun. Exoplanets with a wide range of orbital inclination angles can be found and studied using the polarimetric method. If the starlight is blocked, a simple polarimeter can detect the polarization at various wavelengths because the polarization is so strong. It aids in the investigation of a planet’s atmosphere and chemical makeup.
Key Highlight:
- Indian Institute of Science (IISc) has developed a new method for determining the composition of the atmospheres of extrasolar planets by studying their stars’ light.
- The polarization of light can be used to study planets orbiting stars other than the Sun.
- Exoplanets with a wide range of orbital inclination angles can be found and studied using the polarimetric method.
- If the starlight is blocked, a simple polarimeter can detect the polarization at various wavelengths due to the high level of polarization.
- As a result, we can learn more about the atmosphere and the chemical makeup of exoplanets.
The Indian Institute of Science (IISc), has developed a new method for determining the composition of the atmospheres of extrasolar planets by studying their stars’ light.
According to the research team, light polarization can be used to study planets orbiting stars other than the Sun. According to the DST, existing instruments can detect these polarization signatures or variations in light scattering intensity, and these instruments can also be used to study planets beyond our solar system.
Astronomers have recently discovered that many other stars have planets orbiting them, similar to our solar system. Up to this point, approximately 5,000 such exoplanets have been discovered.
A few decades ago, an IIA scientist suggested that thermal radiation from hot young planets and reflected light from planets orbiting other stars, known as extra-planetary or exoplanets, would also be polarized, and the measure of the polarization could reveal the chemical composition of exoplanetary atmospheres,” the DST stated..
The discovery of polarization in a large number of Brown Dwarfs, a type of failed star with an atmosphere very similar to Jupiter’s, confirmed the prediction and prompted scientists worldwide to build highly sensitive polarimeters and use polarimetric methods to investigate exoplanetary environments.
IIA postdoctoral researcher Aritra Chakrabarty recently developed a detailed three-dimensional numerical method and simulated the polarization of exoplanets with the help of Sujan Sengupta, who is also from IIA. Because of their rapid spin rotation, exoplanets, like their solar-planet counterparts, are slightly oblate.
The team also discovered that only a portion of the planetary disk is illuminated by the star’s light, depending on the planet’s orbital position around the star—non-zero polarization results from the light-emitting region’s asymmetry.
They used all of the asymmetries of an exoplanet’s orbit, including its inclination angle, in their research published in ‘The Astrophysical Journal.’ Their results were averaged over the illuminated and rotation-induced ovaletary surface. They found that the amount of polarization varied depending on the planet you were on concerning the disk’s center.
If the starlight is blocked, a simple polarimeter can detect the polarization at various wavelengths due to the high level of polarization. As a result, we can learn more about the atmosphere and the chemical makeup of exoplanets.
While it’s impossible to see the planet directly because of its polarization, the amount of unpolarized starlight that mixes with the planet’s polarized reflected light is so small that it can still be detected by high-end instruments like the HIPPI, POLISH, and PlanetPol. Aritra Chakrabarty explained that the research would aid in developing devices with appropriate sensitivity and in guiding observers.
While traditional methods can only detect planets that are almost edge-on when observed, the astronomers claim that their polarimetric way can see and probe exoplanets orbiting at a wide range of orbital inclination angles, unlike those used in previous studies.
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