Astronomers have actually determined the oldest star in our galaxy that is accreting debris from orbiting planetesimals, making it one of the earliest rocky and icy planetary systems ever found in the Milky Way.
Their findings conclude that a faint white dwarf located simply 90 light-years from Earth, along with the remains of its orbiting planetary system, are over 10 billion years old. Led by the University of Warwick, the study was released on November 5 in the Monthly Notices of the Royal Astronomical Society.
Most stars, including those like our Sun, will ultimately turn into white dwarfs. A white dwarf is a star that has actually consumed all of its fuel, lost its external layers, and is now undergoing a procedure of contracting and cooling. Any planets in orbit will be disrupted and, in some scenarios, damaged during this process, and their debris will be left to accrete onto the surface area of the white dwarf.
A new research study puts an age to a faint white dwarf star of over ten billion years
Swallowed up remains of recently orbiting planetesimals make this the earliest dead star with a progressed planetary system
Provides insight into the formation and advancement of asteroids, icy moons, and Earth-like rocky planets in the early history of deep space
Artists impression of the old white dwarfs WDJ2147-4035 and WDJ1922 +0233 surrounded by orbiting planetary debris, which will accrete onto the stars and contaminate their environments. A white dwarf is a star that has used up all of its fuel, lost its outer layers, and is now undergoing a process of contracting and cooling. By analyzing the spectrum from WDJ2147-4035, the group discovered the presence of the metals salt, lithium, and potassium and tentatively discovered carbon accreting onto the star– making this the oldest metal-polluted white dwarf found so far.
97% of all stars will end up being a white dwarf and theyre so common around the universe that they are extremely crucial to understand, especially these incredibly cool ones. Formed from the oldest stars in our galaxy, cool white overshadows provide information on the development and advancement of planetary systems around the oldest stars in the Milky Way.”
For this research study, the team of astronomers modeled 2 unusual white overshadows that were discovered by the GAIA area observatory of the European Space Agency. Both stars are polluted by planetary particles.
The astronomers used photometric and spectroscopic information from GAIA, the Dark Energy Survey, and the X-Shooter instrument at the European Southern Observatory to determine for how long the stars have actually been cooling for. They found that the red star WDJ2147-4035 is around 10.7 billion years old, of which 10.2 billion years have been invested cooling as a white dwarf.
Spectroscopy includes analyzing the light from the star at various wavelengths. This can identify when aspects in the stars atmosphere are taking in light at different colors and helps identify what elements those are and how much exists. By examining the spectrum from WDJ2147-4035, the team discovered the existence of the metals sodium, lithium, and potassium and tentatively spotted carbon accreting onto the star– making this the earliest metal-polluted white dwarf found so far.
The second blue star WDJ1922 +0233 is just somewhat younger than WDJ2147-4035 and was polluted by planetary debris of a comparable composition to the Earths continental crust. The science team concluded that the blue color of WDJ1922 +0233, regardless of its cool surface area temperature level, is triggered by its unusual mixed helium-hydrogen atmosphere.
The debris discovered in the otherwise nearly pure-helium and high-gravity atmosphere of the red star WDJ2147-4035 are from an old planetary system that made it through the development of the star into a white dwarf, leading the astronomers to conclude that this is the oldest planetary system around a white dwarf found in the Milky Way.
Lead author Abbigail Elms, a PhD trainee in the University of Warwick Department of Physics, stated: “These metal-polluted stars reveal that Earth isnt distinct, there are other planetary systems out there with planetary bodies similar to the Earth. 97% of all stars will end up being a white dwarf and theyre so common around the universe that they are really crucial to comprehend, especially these very cool ones. Formed from the earliest stars in our galaxy, cool white dwarfs provide info on the formation and evolution of planetary systems around the oldest stars in the Milky Way.”
” Were finding the oldest outstanding remnants in the Milky Way that are polluted by once Earth-like worlds. Its incredible to believe that this taken place on the scale of ten billion years, and that those worlds passed away way prior to the Earth was even formed.”
Astronomers can also use the stars spectra to figure out how quickly those metals are sinking into the stars core, which enables them to recall in time and determine how plentiful each of those metals was in the initial planetary body. By comparing those abundances to astronomical bodies and planetary product discovered in our own solar system, we can rate what those planets would have resembled before the star passed away and ended up being a white dwarf– however when it comes to WDJ2147-4035, that has actually shown tough.
Abbigail discusses: “The red star WDJ2147-4035 is a secret as the accreted planetary particles are extremely lithium and potassium-rich and unlike anything known in our own planetary system. This is an extremely fascinating white dwarf as its ultra-cool surface area temperature level, the metals contaminating it, its old age, and the truth that it is magnetic, makes it incredibly unusual.”
Teacher Pier-Emmanuel Tremblay of the Department of Physics at the University of Warwick said: “When these old stars formed more than 10 billion years earlier, the universe was less metal-rich than it is now, since metals are formed in progressed stars and enormous stellar surges. The two observed white dwarfs offer an interesting window into planetary formation in a metal-poor and gas-rich environment that was different to the conditions when the planetary system was formed.”
Recommendation: “Spectral analysis of ultra-cool white overshadows polluted by planetary debris” by Abbigail K Elms, Pier-Emmanuel Tremblay, Boris T Gänsicke, Detlev Koester, Mark A Hollands, Nicola Pietro Gentile Fusillo, Tim Cunningham and Kevin Apps, 5 November 2022, Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/ mnras/stac2908.
This research received financing from the European Research Council under the European Unions Horizon 2020 research study and development program, the Leverhulme Trust Grant and the UK STFC combined grant.
Artists impression of the old white overshadows WDJ2147-4035 and WDJ1922 +0233 surrounded by orbiting planetary particles, which will accrete onto the stars and contaminate their environments. WDJ2147-4035 is dim and very red, while WDJ1922 +0233 is abnormally blue.
