Maryland

Researchers recently discovered a unique extrasolar planet called “Phoenix” that is capable of retaining its atmosphere by puffing itself up. Phoenix, a Neptune-sized planet, was discovered by a Johns Hopkins University-led team recently. 

Advertisment

An extrasolar planet, also known as exoplanet, is a planet outside our Solar System. There are currently around 5630 such exoplanets in our universe that are residing in different systems, defying our expectations. 

Puff planets, like Phoneix, are comparatively new class of exoplanets which are extremely rare- accounting for some 1 per cent of planets in our galaxy. Such puff planets or super-puff, as they are called, have a mass only a few times larger than Earth’s but have a radius larger than that of Neptune, which gives them a very low mean density. 

Phoenix: Puffiest exoplanet holding onto its atmosphere 

Advertisment

The team discovered Phoenix with the help of data from the Transiting Exoplanet Survey Satellite (TESS) and with the radial velocity measurements obtained by the High Resolution Echelle Spectrometer (HIRES) at the Keck Observatory. 

The data from both the satellite and observatory indicated that Phoenix is 0.55 times the size of Jupiter but only 0.06 times as massive, which orbits a red giant star with a period of approximately 4.2 days. This period is about six times closer to its star than the distance between Mercury and the Sun.

Also Read | After US and Mexico, WHO confirms human case of bird flu in India

Advertisment

Looking at the age and temperature of its star and the planet’s significantly low density, the researchers deduced that Phoenix’s gaseous envelopes should have been stripped away billions of years ago. 

The team also estimates that the planet is the puffiest “puff planet”, based on its density. 

“This planet isn’t evolving the way we thought it would. It appears to have a much bigger, less dense atmosphere than we expected for these systems. How it held on to that atmosphere despite being so close to such a large host star is the big question,” Sam Grunblatt, an astrophysicist with JHU explained in a press release.

Also Read | Astronauts may suffer permanent kidney damage after travelling to Mars: study

“It’s the smallest planet we’ve ever found around one of these red giants, and probably the lowest mass planet orbiting a [red] giant star we’ve ever seen. That’s why it looks really weird. We don’t know why it still has an atmosphere when other ‘hot Neptunes’ that are much smaller and much denser seem to be losing their atmospheres in much less extreme environments.”

Nevertheless, these findings are crucial to predict Earth's atmosphere that it may not evolve the way astronomers previously expected. Instead of our Sun blasting it away, our atmosphere may expand to become incredibly “puffy.”

(With inputs from agencies)