A new instrument will allow mass measurement of exoplanets with extreme precision

A new instrument just mounted on the 3.5-meter WIYN telescope at Kitt Peak National Observatory in southern Arizona promises to detect mass and other characteristics of exoplanets with unprecedented accuracy. In fact, the new instrument, called NEID, will allow an accuracy three times higher than the previous generation of similar instruments.

A high-precision radial velocity spectrometer will collect light from the stars and measure the sometimes minimal gravitational effect that the planets themselves have on the stars around which they orbit. It is a small “wobble” caused by a periodic shift in the speed of the star. This also happens in our solar system. For example, Jupiter, the largest planet, causes an oscillatory movement of the Sun that can be measured in about 30 miles per hour. The Earth, on the other hand, causes a movement of only 0.2 miles per hour.

Of course, the size of the oscillation is proportional to the mass of the planet and this is why it is possible not only to discover the planets themselves but also to measure their mass with extreme precision. The similar instruments used until now can in fact measure this type of oscillation only up to 2 miles per hour but now the NEID will be able to measure oscillations at even shorter speeds, up to one mile per hour, as explained by Jason Wright, a researcher at the State University of Pennsylvania involved in the project. This means that even exoplanets with a land mass can be more easily discovered.

Such an instrument, in collaboration with others such as the TESS space telescope, will therefore allow a greater number of discoveries of exoplanets so that “things will become really interesting and we will be able to learn what planets are made of,” as the scientist himself explains.

The instrument has already been tested with observations of the brightness of the star 51 Pegasi. The instrument can also be updated and can be used by practically all astronomers, as explained by Sarah Logsdon, another researcher involved in the project.