Does a nearby star host an Earth-like planet?
The European Southern Observatory's(ESO) Atacama Large Millimeter/submillimeter Array (ALMA) has made some stunning and insightful observations since its inauguration in 2013, including looks at galaxy formation in the early Universe and snaps of the Milky Way's largest known stellar womb. The telescope's latest effort is one of its mostimpressive yet, providing us with the best-ever look at aplanet-forming disc.
TW Hydrae is a particularly interestingtarget for study, as it's the closest known protoplanetary disc toEarth, meaning that it provides one of our best opportunities to geta good look at how planets form. Located some 175 light-years away,the infant star is just 10 million years old and has a face-onorientation, meaning we can clearly view the structure from Earth.
Previous studies of the star confirmedthe presence of the planet-forming disc, but the new imagery fromALMA provides a much closer look, revealing the presence of gaps inthe material that strongly indicate the presence of infant planets,formed as particles came together and swept through the expanse of dust and gas.
The data was gathered by looking atradio emissions from the tiny, millimeter-sized particles of dust inthe disc. The project was possible thanks to wide separation ofALMA's dishes, which are as much as 15 km (9.3 miles) apart, providingextremely high spatial resolution.
The most intriguing of the gaps in the disc wasfound at a similar distance to that of the Earth from the Sun –some 150 million km (93 million miles) – indicating that the planet that formed it could have some properties similar to Earth. Other notable gaps inthe disc are located three and six billion kilometers fromthe star, putting the presumed planets in orbits similar to Uranusand Pluto.
Broadly speaking, the findings indicate that TW Hydraecould be fairly similar to our own solar system, only in an infantstate. Studying it in greater detail could well reveal new secretsabout how planets like Earth form. Looking forward, the researchers plan to scour thenight sky for similar planet-forming discs, looking to determine howcommon the features found around TW Hydrae are, and how they developover time, and are affected by different conditions.
The new observations aren't the firsttime that ALMA has turned its gaze towards the mysteries of planetformation. Back in 2015, it helped astronomers spot the fingerprints of huge planets sweeping through the clouds of dust and gas surrounding young stars.
The research was published in theAstrophysical Journal Letters.