New Planet Around Our Closest Star

 New Planet Around Our Closest Star

Proxima Centauri is the closest star to our solar system. It lies 4.2 light-years away. In mid-February, a new planet was discovered orbiting Proxima Centauri. There were already two recorded planets orbiting the star, so this discovery labels this stellar system as a three-planet stellar system. 

This new planet, Proxima d, is not a suitable environment for life. With an orbital speed of 5 days, its semimajor axis places the planet in a location where it is too warm for water to exist in its liquid state. 

This planet was found by measuring the wobble of Proxima Centauri, also known as the radial method. The way this method was employed in Proxima d’s case might give way to finding more planets in this method. 

In order to find Proxima d, they had to record Proxima Centauri’s wobble which is  approximately a 40 cm/s movement. This extremely small detection was made possible by the ESPRESSO spectrograph that is part of the VLT in Chile that we talked about in class. ESPRESSO has an extremely high resolution. 

Proxima d is thought to be approximately ¼ of Earth’s mass and double that of Mars’. It is also 8 times closer in orbit than mercury’s orbit, or approximately 0.03 AU. There is no possible way there is any water, however, there is a possibility of an atmosphere. 

Following this discovery, it is shown that ESPRESSO can find planets of smaller masses than ever before due to its extremely small uncertainty. Beforehand, any other measurements for planets of this size were too comparable to stellar noise making it impossible up until this point.