An investigation carried out by the astrophysicists of the Instituto de Astrofísica de Canarias (IAC) Zofia Chrobáková, a doctoral student at the IAC and the College of La Laguna (ULL), and Martín López Corredoira, issues one particular of the most intriguing results about the dynamics of the Milky Way in new years: that the precession, or the wobble in the axis of rotation of the disc warp is incorrect. The final results have just been revealed in The Astrophysical Journal.
The Milky Way is a spiral galaxy, which indicates that it is composed, amid other components, of a disc of stars, gas and dust, in which the spiral arms are contained. At first, it was believed that the disc was entirely flat, but for some decades now it is regarded that the outermost aspect of the disc is distorted into what is termed a “warp”: in one particular course it is twisted upwards, and in the reverse course downwards. The stars, the gas, and the dust are all warped, and so are not in the very same plane as the extended interior aspect of the disc, and an axis perpendicular to the planes of the warp defines their rotation.
In 2020, an investigation announced the detection of the precession of the warp of the Milky Way disc, which indicates that the deformation in this outer region is not static, but that just like a spinning leading the orientation of its axis is itself rotating with time. Also, these researchers located that it was more quickly than the theories predicted, a cycle each individual 600-seven-hundred million years, some three occasions the time it requires the Sun to travel when round the centre of the Galaxy.
Precession is not a phenomenon which takes place only in galaxies, it also comes about to our world. As nicely as its once-a-year revolution all over the Sun, and its rotation interval of 24 several hours, the axis of the Earth precesses, which implies that the celestial pole is not constantly close to the present pole star, but that (as an case in point) fourteen,000 years in the past it was close to the star Vega.
Now, a new review by Zofia Chrobáková and Martín López Corredoira has taken into account the variation of the amplitude of the warp with the ages of the stars. The review concludes that, applying the warp of the old stars whose velocities have been calculated, it is possible that the precession can vanish, or at minimum become slower than what is presently thought. To get there at this result the researchers have used information from the Gaia Mission of the European Space Agency (ESA), analysing the positions and velocities of hundreds of hundreds of thousands of stars in the outer disc.
“In preceding scientific studies it experienced not been observed,” clarifies Zofia Chrobáková, a predoctoral researcher at the IAC and the first writer of the article, “that the stars which are a couple tens of hundreds of thousands of years old, these as the Cepheids, have a much bigger warp than that of the stars noticeable with the Gaia mission, which are countless numbers of hundreds of thousands of years old.”
“This does not always mean that the warp does not precess at all, it could do so, but much a lot more slowly and gradually, and we are likely unable to measure this motion right up until we obtain better information,” concludes Martín López Corredoira, and IAC researcher and co-writer of the article.