There are many star systems in the Milky Way. Most of these systems are composed of two stars, but others contain three, four, or even six stars.
Stable systems tend to be stable since unstable systems tend to break apart quickly, but sometimes you can get a kind of meta-stable system. It's stable enough for stars to evolve while still being young. That end could be a big deal.
It all comes down to the dynamics of gravity. In physics, two objects in isolation are always stable. elliptical orbits are the only paths they can have. The most common multiple star systems are simple binaries.
Things get more complicated when you have more than one mass. There isn't an exact solution to the three-body problem.
We can make accurate models. We can create an accurate model if we make precise measurements of the stellar motions.
These models will make good predictions over millions of years. HD 74438 is an interesting star system.
It was discovered by the Gaia-ESO Survey. The telescopes at Gaia aren't powerful enough to observe individual stars, but we know they are because of their stellar spectrum.
The stars' relative motion causes each star to have a slightly different wavelength of light. We can calculate their speed and motion.
The motion of HD 74438. The Mt John Observatory is located at the University of Canterbury.
In a recent article in Nature Astronomy, a team used ground-based observations to pin down the stars' positions.
They confirmed that the stars are in a 2 + 2 configuration, where they are in close proximity to each other. They were able to show that the tug of the outerbinary is making the innerbinary unstable.
HD 74438 is very young. It is part of an open cluster that is 43 million years old. All of the stars have the same mass as the Sun.
The stars are likely to die as white dwarfs. The stars could live long enough to become white dwarfs because of the small instability of the system. They could collide in the end because of their unstable orbits.
The HD 74438 is a perfect example of how a multiple star system could evolve to create a merger of white dwarfs.
White dwarf mergers are a way that type Ia supernovae occur. The supernovae play a major role in our measurement of expansion. HD 74438 is a multiple star system.
The study shows that double binaries can be in an unstable long-term relationship.
Nature Astronomy has published the research.
The article was published by Universe Today. The original article is worth a read.
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