News | February 21, 2020
Discovery Alert: This Four-planet System is Leaking
Planets: DMPP-1 d, e, c and b
The discovery: Three "hot super-Earths" and a "warm Neptune" orbit a relatively nearby, bright star not unlike our own Sun, a new study suggests. One or more of these planets is so thoroughly cooked that its atmosphere appears to be leaking into space – in fact, that's how astronomers found these planets using a brand-new detection method.
Key facts: DMPP-1 belongs to the class of stars labeled "F": a bit larger and hotter than our Sun, which is a "G"-type star. DMPP-1 is also more yellow-white than our yellow star. The name itself stands for the "Dispersed Matter Planet Project," and it's the first star with planets detected by searching for the gas that they're venting into space.
Details: A team of scientists led by Carole Haswell and Daniel Staab of the U.K.'s Open University tried out their new search method using a 3.6-meter telescope in Chile. Relying on an instrument called a spectrograph, they zeroed in on a star about 200 light-years away. The spectrograph can reveal what types of gases are present in a planetary system, and in this case, found evidence of a possible "circumstellar gas shroud" – a diffuse cloud of gas orbiting the star, likely bleeding into space from one or more of the inner, "super Earth" planets. The team used radial velocity measurements, which track the wobbles of a star caused by the gravity of orbiting planets, to estimate the size and number of planets in this system.
Fun facts: The planet, or planets, that are leaking gas could shed light on the "Neptune desert" – an orbital region so close to a star that Neptune-type planets migrating inward from the outer reaches of the system would have their atmospheres stripped away, leaving behind nothing but a rocky core. It's possible the gas-hemorrhaging planet, or planets, are in the late stages of this process.
The discoverers: The overall Dispersed Matter Planet Project Survey, led by Haswell, used the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph on the European Southern Observatory's 3.6-meter telescope in La Silla, Chile. This international science team studied stars now known as DMPP-1, 2 and 3. The paper on DMPP-1, led by Staab, was published in "Nature Astronomy" in December 2019, and the discoveries were entered into the NASA Exoplanet Archive in January 2020.