The hunt for exoplanets in the universe has always depended on our ability to observe the invisible. Until now we have mainly noticed the flickering of a star when it passes in front of one of these planets or the subtle gravitational wobble that it causes, but we have never seen them directly. Now a team of astronomers has perfected a much more ingenious method: searching for planets based on the “false” magnetic quiet of their stars.
And now it works. The project known as the Dispersed Matter Planet Project (DMPP) has just confirmed the discovery of seven new planets spread across five star systems, and its projections indicate that there could be hundreds of rocky worlds hidden in our closest cosmic neighborhood. And we have not been able to ‘see’ all of these with our traditional systems.
How it works. The DMPP method is fascinating because it turns the traditional way of observing the universe on its head. Now, instead of looking for active stars, the team selects bright, very nearby stars that have anomalously low calcium emission. In fact, they show levels of magnetic activity below their basal level.
But these samples do not indicate that the star is without activity, but rather that it is hidden. Here astronomers have discovered that these systems host planets very close to the star, which due to the intense heat are evaporating. From this gas that is released from these worlds, a kind of ‘shield’ or orbital cloud is formed that absorbs radiation and hides the activity of the stellar chromosphere. That is, the star’s apparent inactivity is the gas “fingerprint” of a disintegrating planet.
Its precision. To confirm these suspicions, the team does not stop at observing the gas, since it uses extremely high-precision radial velocity spectrographs such as HARPS-N, which are capable of measuring minute variations in the movement of the star.
One of the project’s most intriguing case studies is the DMPP-4 system, located about 25 parsecs away. In this star, candidates for planets with sub-Neptunian masses have already been detected, on the order of between 8 and 12.2 times the mass of the Earth, orbiting at breakneck speeds, with “years” that last only between 2 and 5 days.
Where are they? These planets inhabit what astronomers know as the “Neptunian Desert,” a region very close to the star where planets the size of Neptune are rarely found. The leading theory is that these worlds are actually rocky cores of ancient Neptunes that migrated into the system and whose atmospheres were swept away by intense stellar radiation.
Many to discover. The implications of this study are massive for modern astrophysics, as data from the DMPP project suggests that between 10% and 20% of these low magnetic activity stars could host compact systems of rocky planets that we have not known about until now. This not only helps explain certain anomalies in the historical catalogs of the Kepler telescope, but gives us a treasure map.
Being such bright star systems close to Earth, these newly discovered exoplanets become the perfect candidates to be observed by the James Webb Space Telescope (JWST) and the future generation of Extremely Large Telescopes (ELT).
Images | NASA Hubble Space Telescope
In WorldOfSoftware | A new “solar system” has just been discovered. There’s just one problem: it shouldn’t exist.
