New way to measure gravity can spot alien life - The TeCake
In a breakthrough, astronomers have developed a new method for calculating gravity of very distant stars. Astronomers believe the new technique can help in searching alien life on exoplanets located in other galaxies.

To solve the mystery of alien life, a team of astronomers has discovered a new method to measure gravity at the surface of distant stars to spot alien life. They revealed that their new process could determine whether distant stars with planets orbiting them can harbour life.

The astronomers believe that calculating the surface gravity of a star is essentially measuring how much the body would weigh on that star. Also, if the celestial body had a rigid surface on which the body could be placed, then its weight would vary from star to star.

Moreover, the new study enables us to calculate surface gravity with an accuracy of about four percent, for stars too distant and too faint to apply current techniques. As it totally depends on the planet’s mass and its radius, as we measure our weight on Earth with our mass, Earth’s mass and its radius. This technique will enable astronomers to better gauge the masses and sizes of distant stars.

“If you don’t know the star, you don’t know the planet. The size of an exoplanet is measured relative to the size of its parent star,” said study co-author and professor Jaymie Matthews from the University of British Columbia.

He further explained that if you find a planet around a star that you think is Sun-like but is actually a giant, you may have fooled yourself into thinking you’ve found a habitable Earth-sized world. “Our technique can tell you how big and bright is the star, and if a planet around it is the right size and temperature to have water oceans, and maybe life,” Matthews added.

The team calls their new method of measuring gravity as “autocorrelation function timescale technique”, or ‘timescale technique in short. The technique uses subtle variations in the brightness of distant stars recorded by satellites like Canada’s MOST and NASA’s Kepler missions.

Future space satellites will hunt for planets in the ‘Goldilocks Zones’ of their stars. Not too cold, not too hot, but just right for liquid water oceans and maybe life. Future exoplanet surveys will need the best possible information about the stars, which they search for. While it will only be possible if they could correctly characterise any planet, they find till then.

“The timescale technique is a simple but powerful tool that can be applied to the data from these searches to help understand the nature of stars like our Sun and to help find other planets like our Earth,” explained lead author Thomas Kallinger from the University of Vienna.

Researchers and scientists will be glad and exited to study the planets beyond the Solar System. While, some of them are too distant from the Earth that even the basic properties of the stars they orbit can’t be measured accurately.

The new technique is explained in a study published in the journal Science Advances.

Abstract:

A significant part of the intrinsic brightness variations in cool stars of low and intermediate mass arises from surface convection (seen as granulation) and acoustic oscillations (p-mode pulsations). The characteristics of these phenomena are largely determined by the stars’ surface gravity (g). Detailed photometric measurements of either signal can yield an accurate value of g. However, even with ultraprecise photometry from NASA’s Kepler mission, many stars are too faint for current methods or only moderate accuracy can be achieved in a limited range of stellar evolutionary stages. This means that many of the stars in the Kepler sample, including exoplanet hosts, are not sufficiently characterised to fully describe the sample and exoplanet properties. We present a novel way to measure surface gravities with accuracies of about 4%. Our technique exploits the tight relation between g and the characteristic time scale of the combined granulation and p-mode oscillation signal. It is applicable to all stars with a convective envelope, including active stars. It can measure g in stars for which no other analysis is now possible. Because it depends on the time scale (and no other properties) of the signal, our technique is largely independent of the type of measurement (for example, photometry or radial velocity measurements) and the calibration of the instrumentation used. However, the oscillation signal must be temporally resolved; thus, it cannot be applied to dwarf stars observed by Kepler in its long-cadence mode.

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