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Astronomers have discovered as many as three possible super-Earth planets around a star very close to us.
The star is the orange dwarf HD 48498, which is 55 light-years away. The discovery was made by an international team of researchers led by Shweta Dalal of the University of Exeter in the UK.
These are still planet candidates, but if they do exist, one of the planets would orbit the star in 7 days, the second in 38 days, and the third in 151 Earth days.
The last one is the farthest from the star and is right in the habitable zone, where the temperature is neither too hot nor too cold and water is liquid.
The discoverer points to the Royal Astronomical Society Monthly Newsletterthe star in which the planet is very similar to our sun.
The planetary system, if it is still a planetary system, is the closest to our own solar system, located near a Sun-like star, and also contains a super-Earth orbiting in the habitable zone.
Exoplanets that are more massive than Earth but still much smaller than the giant solar system planets Uranus and Neptune are called super-Earths.
To discover the candidate planet, scientists spent a decade taking precise measurements, using a spectrograph to measure tiny changes in the star’s radial velocity.
The radial velocity is the component of the velocity of a star that lies in our line of sight, i.e. it shows how fast the star is moving away from us or approaching us. Planets orbiting a star use their gravity to modify the star’s motion, including the radial velocity.
However, changes in radial velocity can be detected by spectroscopic measurements, because the spectral lines shift slightly here and there due to the Doppler effect.
The principle is simple, but the measurement itself requires carefulness and persistence, and the analysis of the measurement results requires BroadCast Unitedligence.
The analysis revealed, among other things, that the three planets are between five and eleven times more massive than Earth.
The system may be close enough to us that scientists hope we’ll one day be able to visually see at least the most distant planet from its star.
Vikerradio broadcasts science news around 8:35 am Monday to Friday and around 8:25 am on Saturdays.
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