The European Space Agency's Gaia mission has spotted an unusual family of stars all strangely eager to leave home -- a family we couldn't have discovered without the star-surveying spacecraft, and one unlike all others we have spotted to date.
Stars in the Milky Way tend to form in families, with similar stars springing to life in roughly the same place at roughly the same time. These stars later head out into the wider galaxy when they're ready to fly the nest. While smaller groups can completely dissipate, siblings from sizeable families usually move similarly and largely travel together.
We have seen many star families with Gaia. We've spotted strings of stars stretching out across the Milky Way and remaining intact for billions of years, mapped the ancient star streams that wound together to form the earliest structure of our galaxy, and put together a stellar 'family portrait' of our cosmic home.By studying star families we can piece together not only the characteristics and behaviour of the stars themselves, but also learn about how our galaxy is evolving as a whole.
A family like no other
Using Gaia data, scientists have now spotted a star family unlike any other: a massive family of over 1000 young stars behaving oddly. Despite its size, the family -- dubbed Ophion -- will soon have completely dispersed in record time, leaving just an empty nest behind.
"Ophion is filled with stars that are set to rush out across the galaxy in a totally haphazard, uncoordinated way, which is far from what we'd expect for a family so big," says Dylan Huson of Western Washington University (WWU), USA, and lead author of the discovery paper. "What's more, this will happen in a fraction of the time it'd usually take for such a large family to scatter. It's like no other star family we've seen before."
A new model
To find Ophion, Dylan and colleagues developed a new model to explore Gaia's vast, unrivalled trove of spectroscopic data and learn more about young, low-mass stars lying reasonably near to the Sun. They applied this model, named Gaia Net, to the hundreds of millions of stellar spectra released as part of Gaia's data release 3. They then narrowed their search to 'young' stars of under 20 million years in age -- and out jumped Ophion.
"This is the first time that it's been possible to use a model like this for young stars, due to the immense volume and high quality of spectroscopic observations needed to make it work," adds ESA Gaia Project Scientist Johannes Sahlmann. "It's still pretty new to be able to reliably measure the parameters of lots of young stars at once. This kind of bulk observing is one of Gaia's truly unprecedented achievements."
Source: ScienceDaily
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