AstroTalk Episode March 9, 2017

Glutinous Star May Hold Clues To Planet Formation

3:05pm - 3:26pm

The young star FU Orionis suddenly began devouring material from the gas and dust surrounding it, in 1936. Over a 3 month super-binge, the star flared up 100 times brighter, and its termperature rose to 7,000 degrees Kelvin. Since 1936, FU Ornionis has continued to gobble up surrounding gas, but not at quite the same rate. The star is roughly the size of our Sun, and to this point, FU Ornionis has reached the point of being the brightest young star ever seen, for a star the size of our Sun. Scientists are now trying to figure out what the implications of this sudde4n heating is for how planets form. The chemistry of FU Orionis is thought to have changed with its heating, so the material in the disk that would make up planets also changed. Scientists believe this look at FU Orionis is just like looking back at the younger, formative, or baby years of the formation of our solar system. The intense baking of the star's surrounding disk likely changed its chemistry, permanently altering material that could one day turn into planets. Our solar system could have gone through a similar brightening change when it was forming. Scientists will now turn to studying FU Orionis at infrared wavelengths, to gather more data about this Sun-like star. Over the past years, FU O has devoured or eaten the equivalent weight of 80 Jupiters (or about 8,000 Earths). Scientists estimate that FU O will continue to snack on surrounding gas and dust for a few hundred more years, before it returns to its pre-1936 brightening level. The amount of visible and infrred light energy coming from FU O has decreased by 13% over the past 1 2 years. The dimming is thought to have occurred at shorter infrared wavelengths, not at longer wavelengths. This implies that 13% of the hotter material material has disappeared, while colder material remains, so it seems that only the inner part of the proto-lanetary disk has been eaten by FU O. The colder outer part has remained intact. This could have tremendous implications for how planets closer of farther from a star, like Earth or Mars, could have formed, or could have been influenced. The heating of the disk, and the changing of its chemical compositon at certain distances out from a star, could help explain the relative abundance of certain elements on Earth as opposed to Mars, or vice versa. FU Orionis is 1,500 light years from Earth, in the constellation of Orion.