40 Eri B is the second brightest white dwarf and among the first to be discovered in 1783. White dwarfs were once normal stars similar to the Sun but collapsed after exhausting all their fuel.
Since the discovery of the first white dwarf, astronomers have tried to gain more insights into white dwarfs to get a deeper understanding of the evolutionary history of our home galaxy.
Daniel Mikkola, a doctoral student in astronomy at Lund University, said, “Thanks to observations from the Gaia space telescope, we have managed to reveal the three-dimensional velocity distribution for the largest catalog of white dwarfs for the first time to date. This gives us a detailed picture of their velocity structure with unparalleled detail.”
Using data from Gaia, astronomers measured the positions and velocities of about 1.5 billion stars. They have recently been able to concentrate entirely on the white dwarfs in the Solar neighborhood.
Mikkola said, “We have managed to map the white dwarfs’ velocities and movement patterns. Gaia revealed two parallel sequences of white dwarfs when looking at their temperature and brightness. If we study these separately, we can see that they move in different ways, probably as a consequence of them having different masses and lifetimes.”
According to astronomers, the study could help them develop new simulations and models to continue to map the history and development of the Milky Way. By learning more about white dwarfs, they will be able to clear up some of the mysteries surrounding the Milky Way’s formation.
Mikkola said, “This study is important because we learned more about the closest regions in our galaxy. The results are also interesting because our star, the Sun, will one day turn into a white dwarf just like 97 percent of all stars in the Milky Way.”
- Daniel Mikkola, Paul J. McMillan et al. The velocity distribution of white dwarfs in Gaia EDR3. arXiv: 2202.07672v1