In 2012, astronomers detected a fuel large transiting in entrance of WASP-49A, a G-type star positioned about 635 light-years from Earth. The info obtained by the WASP survey indicated that this exoplanet (WASP-49 b) is a fuel large roughly the identical measurement as Jupiter and 37% as large. In 2017, WASP-49 b was discovered to have an in depth cloud of sodium, which was confounding to scientists. Additional observations in 2019 utilizing the Hubble House Telescope detected the presence of different minerals, together with magnesium and iron, which seemed to be magnetically certain to the fuel large.
WASP-49 b and its star are predominantly composed of hydrogen and helium, with solely hint quantities of sodium – not sufficient to account for this cloud. As well as, there was no indication of how this sodium cloud was ejected into house. In our Photo voltaic System, fuel emissions from Jupiter’s volcanic moon Io create an analogous phenomenon. In a latest research, a world staff led by scientists from NASA’s Jet Propulsion Laboratory discovered potential proof of a rocky, volcanic moon orbiting WASP-49 b. Whereas not but confirmed, the presence of a volcanic exomoon round this fuel large may clarify the presence of this sodium cloud.
The research was led by Apurva Oza, a former postdoctoral researcher at NASA’s Jet Propulsion Laboratory and now a workers scientist at Caltech. He was joined by colleagues from NASA JPL and researchers from the European Southern Observatory (ESO), the Indian Institute of Astrophysics, the Caltech/IPAC-NASA Exoplanet Science Institute, the Institute of Science and Expertise Austria (ISTA), the Birla Institute of Expertise and Science, and a number of universities. The paper that particulars their findings was just lately printed in The Astrophysical Letters.
Io is essentially the most volcanic physique in our Photo voltaic System, with a whole bunch of energetic volcanoes and in depth lava formations. This exercise is the results of tidal interplay with Jupiter’s highly effective magnetic area, which causes the inside of Io to flex and contract, creating dense lava flows that break by way of the floor. These volcanoes spew lava as much as 300 km (186 mi) into house, together with sulfur dioxide, sodium, potassium, and different gases, creating an enormous cloud round Jupiter as much as 1,000 occasions the planet’s radius.
Whereas the staff’s observations didn’t detect any exomoons immediately round WASP-49 b, an enormous sodium cloud may represent oblique proof of a volcanic moon that is just too small and dim to detect. For years, Oza has investigated how exomoons is likely to be detected by way of their volcanic exercise. To find out if this was the case round WASP-49 b, he and the staff noticed WASP-49 b over time utilizing the Echelle SPectrograph for Rocky Exoplanets and Secure Spectroscopic Observations (ESPRESSO) on the ESO’s Very Giant Telescope (VLT).
This proved fairly difficult due to the space concerned and the way in which the star, planet, and cloud typically overlap, making it very tough to differentiate between them. However, their observations revealed a number of items of proof that recommend {that a} separate physique is accountable for the sodium cloud. For instance, their observations indicated that the cloud immediately elevated in measurement throughout two observations, suggesting it was being replenished. In truth, they estimate that the cloud is replenished at a fee of 100,000 kg (220,000 lbs) per second.
Additionally they noticed the cloud shifting sooner than the planet, suggesting it was generated by one other physique orbiting sooner than the planet. “We expect it is a actually crucial piece of proof,” stated Oza. “The cloud is shifting in the wrong way that physics tells us it needs to be going if it had been a part of the planet’s ambiance.” Their observations additionally famous one thing fascinating as WASP-49 b orbited its mother or father star each 2.8 days. Throughout this time, the cloud appeared and disappeared behind the star or the planet irregularly.
To deal with this, the staff additionally used a pc mannequin to simulate the presence of an exomoon and evaluate it to their observations. Their outcomes confirmed that an exomoon with an orbital interval of eight hours may clarify the cloud’s movement and exercise, together with the way it appeared to cross in entrance of the planet and can disappear and reappear at intervals. One other takeaway from this research was what it suggests about this attainable exomoon’s future.
If WASP-49 b is analogous in measurement to Earth’s Moon, Oza and his colleagues estimate that the tidal interplay with the planet’s gravity and its speedy mass loss will finally trigger it to disintegrate. “If there actually is a moon there, it’ll have a really harmful ending,” stated Oza. Whereas these observations are intriguing, the staff emphasizes that follow-up observations are wanted to be taught extra in regards to the cloud’s orbit and construction.
Additional Studying: NASA, The Astrophysical Letters
