Baffling age-defying star offers new clues to odd behavior
Scientists have been studying the star (called IRAS 19312+1950) for the last 16 years and have repeatedly failed to determine if it is extremely young or extremely old.
“Astronomers recognized this object as noteworthy around the year 2000 and have been trying ever since to decide how far along its development is,” said Martin Cordiner, an astrochemist at NASA’s Goddard Space Flight Center in Maryland.
NASA researchers initially thought the star was an elderly ‘red supergiant’ (a name given to the largest stars in the universe by volume), but a new study by a fresh team has classified it as something completely different, a protostar - a star in its earliest stage of formation.
This is IRAS 20324+4057...— Learn to Skywatch (@Learntoskywatch) June 11, 2016
A protostar better known as the "Cosmic Caterpillar"
Image: NASA/ESA/STScI/AURA/IPHAS pic.twitter.com/AoKSZ4oJoB
Located more than 12,000 light-years from Earth and lodged deep within the Milky Way, some researchers suspected the massive oxygen-rich star may have simply reached its peak and begun to decline.
There have been some clues that suggest the star is old: When stars reach the later part of their lifespan, they have used up most of their hydrogen and so rely on heavier fuels that don’t last as long, IRAS has emitted a maser (an intense radio source) that “is almost exclusively associated with late-stage stars”.
However, the IRAS is also surrounded by a large chemical-rich cloud that is usually observed in the regions where new stars are born, yet there are no “stellar nurseries” near this star.
At the centre of this NASA/ESA Hubble Space Telescope image, a star known as IRAS pic.twitter.com/7e1uQatWbh— My country? Europe. (@MycountryEurope) March 8, 2016
Theories to explain the star’s complexities range from the possibility that the surrounding cloud resembles the one associated with new stars, to the idea that telescopes may be somehow capturing images of both an old star and a new star in the making together.
Now, new data analysis using NASA’s Spitzer Space Telescope and ESA’s Herschel Space Observatory have lead Cordiner and his team to believe that the star is, in fact, in its very early stage of formation.
The new data indicates that the star is burning much brighter than when it was first observed - emitting about 20,000 times the energy of the sun - and there are large amounts of ice from water and carbon dioxide in the cloud that surrounds it.
“We think the star is probably in an embryonic stage, getting near the end of its accretion stage – the period when it pulls in new material to fuel its growth,” said Cordiner.
The team does acknowledge that, while we now know more than ever about the mysterious object, its peculiar features mean it is not your typical protostar.