Astronomers have developed a new way to measure cosmic distances by listening to the frequencies of the “music” played by pulsating stars that collectively act like a vast orchestra of different cosmic instruments.
Results may help European Space Agency (ESA) satellite Gaia can better measure the positions of approximately two billion stars, as well as their distances to the stars. Soil Gestures and movements while creating a precise, 3D map Milky Way.
Scientists often use a process called: parallax, the apparent change in the position of an object when viewed from two different positions, to measure the distance to various stars. They then measure the star’s angles using Gaia’s position. space, try to triangulate. But the problem is that the further away a star is, the smaller the apparent displacement of the parallax. And the smaller the parallax displacement, the more likely small systematic errors will occur, potentially biasing the measurements.
A research team, including scientists from the Federal Institute of Technology in Lausanne (EPFL) and the University of Bologna, is working to eliminate these errors. In short, they developed the most sensitive observations yet of more than 12,000 oscillations. red giant stars.
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“We measured Gaia biases by comparing reported parallaxes. satellite with the same parallaxes stars “We determined it using asteroseismology,” said Saniya Khan, a researcher from the EPFL Standard Candles and Distances group who led the latest study. he said in a statement.
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The team’s analysis of stellar oscillations is called “asteroseismology” and is similar to how geologists study the structure of the Earth by watching patterns in stars. earthquakes.
Khan and his colleagues used the sample stars’ vibrations and oscillations, which can be seen as tiny changes in light intensity, to convert them into sound waves. In turn, they were able to detect a spectrum of relevant sound frequencies. It was then possible to convert these stellar audio frequencies into distance measurements.
“The frequency spectrum allows us to determine how far away a star is, allowing us to obtain asteroseismic parallaxes,” Khan said. “In our study, we listened to the ‘music’ of a large number of stars; as many as 15,000 of them.” light years far!”
The vocal range also gave the team more information about the stars in their sample, helping them pick out the cosmic instruments in this celestial orchestra.
“By analyzing the frequency spectrum of stellar oscillations, we can estimate the size of a star, just as you can describe the size of a musical instrument by the type of sound it makes – think of the difference in pitch between a violin and a cello.” Andrea Miglio said in the statement:
When the team used this method to calculate a star’s size, its brightness could also be calculated. This brightness is also comparable to how bright the star appears to us as we stand here on Earth. This information was combined with observations of the stars’ temperatures and chemical makeup to calculate the final distance.
This calculated distance was then used to determine the parallax that could be controlled by comparing it with the parallaxes obtained by Gaia during data collection. It was like a large-scale check of the ESA mission’s measurement accuracy.
“Gaia has increased the number of stars whose parallaxes have been measured by a factor of 10,000, a huge increase in accuracy over its predecessor, the ESA Hipparcos mission,” said Richard Anderson, leader of the EPFL Standard Candles and Distances research group. expression. “Asteroseismology is the only way we can check Gaia’s parallax accuracy across the entire sky, that is, for both low- and high-density stars.”
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Just like the stars it studies, this distance measurement method based on asteroseismology may have a bright future.
“Upcoming space missions such as TESS and PLATO aim to detect and investigate outer planets “It will use asteroseismology and deliver the necessary datasets to ever-expanding regions of the sky,” Khan concluded. “Methods like ours will therefore play a crucial role in improving Gaia’s parallax measurements, which will help us pinpoint our location on Earth.” Universe and take advantage of numerous subdomains astronomy And astrophysics“
The team’s research was published in the journal In September. Astronomy and Astrophysics.