Incredibly Dense Planet Discovered That Challenges Planet Formation Theories

Researchers have discovered an incredibly dense young exoplanet that is orbiting a young star in the Hyades cluster. The researchers say that the planet is unusually dense for its size and age. It's estimated to weigh in at 25 Earth-masses and is slightly smaller the Neptune. The existence of the planet puts it at odds with leading planet formation theories.The exoplanet is known as K2-25b, and the observations were performed with the WIYN 0.9-meter telescope at Kitt Peak National Observatory. The planet is dense enough for its age and size that scientists are questioning how it came to exist. The planet orbits an M-dwarf star, which is the most common type of star in the galaxy. One complete orbit takes 3.5 days.

The star's system is approximately 600 million years old and about 150 light-years away from Earth. Scientists have determined that planets with sizes between the Earth and Neptune are the most common companions to stars in the Milky Way.

K2-25b has a mass 25 times that of the Earth. Researchers say that it's nearly all core and has a tiny gaseous envelope. Scientists are trying to determine how with such a high mass and resulting strong gravitational pull that the planet avoided accumulating a significant gaseous envelope.

The size of the exoplanet was initially measured by the Kepler satellite and later refined using the WIYN telescope. Interestingly, one of the key breakthroughs for such accurate measurements of this exoplanet was a Engineered Diffuser made from off-the-shelf components for around $500. That diffuser is attached to the telescope and spreads the star's light out to cover more pixels on the camera for more accurate measurements. Scientists are continuing to study K2-25b, and for now, it's a mystery.