thanks : India Today
dedicated by: Kavignar Thanigai
This solar system has two suns and the debris of a world with a similar composition to the Earth’s continental crust.
- Astronomers identified the oldest star in our galaxy
- The fate of most stars, including those like our Sun, is to become a white dwarf
- The team used spectroscopic and photometric data from GAIA
By India Today Web Desk: The universe has been over 13.7 billion years old and has seen several planetary systems born, grow old and die. Astronomers on Earth have for the first time discovered the remains of the oldest solar system in the Milky Way galaxy. The debris of the planetary system is just 90 light-years from Earth.
Astronomers identified the oldest star in our galaxy that is accreting debris from orbiting planetesimals, making it one of the oldest rocky and icy planetary systems discovered in our galaxy. This planetary system orbited a faint white dwarf star and the remains of the solar system discovered are at least 10 billion years old.
A white dwarf is a star that has burnt up all of its fuel and shed its outer layers and is now undergoing a process of shrinking and cooling. The fate of most stars, including those like our Sun, is to become a white dwarf and scientists have said that when a star loses its end of life any orbiting planets will be disrupted and, in some cases, destroyed.
The details of the findings have been published in the Monthly Notices of the Royal Astronomical Society. The team of astronomers modelled two unusual white dwarfs that were detected by the space observatory GAIA of the European Space Agency. Both the stars are polluted by planetary debris.
While one of them was spotted to be blue the other is the faintest and reddest found to date in the local galactic neighbourhood.
When these old stars formed more than 10 billion years ago, the universe was less metal-rich than it is now since metals are formed in evolved stars and gigantic stellar explosions. The two observed white dwarfs provide an exciting window into planetary formation in a metal-poor and gas-rich environment that was different to the conditions when the solar system was formed,” Professor Pier-Emmanuel Tremblay of the Department of Physics at the University of Warwick, said in a statement.
he team used spectroscopic and photometric data from GAIA, the Dark Energy Survey, and the X-Shooter instrument at the European Southern Observatory to analyse how long it has been cooling. The star named WDJ2147-4035 is around 10.7 billion years old, of which 10.2 billion years have been spent cooling as a white dwarf.
The second ‘blue’ star WDJ1922+0233 is only slightly younger than WDJ2147-4035 and was polluted by planetary debris of a similar composition to the Earth’s continental crust.
“We’re finding the oldest stellar remnants in the Milky Way that are polluted by once Earth-like planets. It’s amazing to think that this happened on the scale of ten billion years and that those planets died way before the Earth was even formed.” Lead author Abbigail Elms, a Ph.D. student at the University of Warwick said.