The ‘songs’ of the stars reveal their distance from Earth; understand

Astronomers have developed a revolutionary technique for measuring distances in space: using the “music” produced by the stars. This approach promises to provide significant support to the European Space Agency’s (ESA) Gaia satellite, whose mission is to measure the positions and distances of around two billion stars. This will help create a three-dimensional map of the Milky Way.

For those in a hurry:

Traditional methods for measuring stellar distances, such as the parallax method, face accuracy challenges for more distant stars. The research, conducted by scientists from the Federal Institute of Technology in Lausanne (EPFL) and the University of Bologna, overcomes these limitations by developing accurate observations of more than 12,000 oscillating red giant stars.

The ‘music’ of the stars

The article, published in the magazine Astronomy and astrophysicspresents a new method for detecting and measuring the polarization of the cosmic microwave background (CMB).

The technique, known as asteroseismology, analyzes stellar oscillations to measure distances. It’s a bit like using earthquakes to study the geology of our planet. The vibrations of the stars are converted into sound waves and associated frequencies, which are used to determine distances.

This analysis of the frequency spectrum of stars allows us to estimate the size of stars, similar to identifying the size of a musical instrument by the sound it produces. Once the size of the star is calculated, it is possible to determine its brightness, which, when compared with its appearance from Earth, helps calculate the distance.

How does it work

The method is based on the analysis of CMB image data obtained from radio frequency telescopes. CMB images are obtained by dividing the sky into small regions, called pixels. The polarization of the CMB is represented by two components, called linear polarization and circular polarization. The proposed method uses a machine learning algorithm to separate the two components of the CMB polarization.

Using this technique it is possible to detect the polarization of the CMB with high precision, even in regions with low signal intensity. This is important because the polarization of the CMB is weaker than its intensity. And regions with low signal intensity are generally the most interesting for studying the CMB, as they can provide information about the early phases of the Universe.

Asteroseismology was applied to data from ESA’s Planck, a radio frequency space telescope launched in 2009. The telescope provided high-quality data from the CMB, which was used to study the evolution of the Universe.

Importance and next steps

The results of the article show that this method is a promising tool for studying CMB. Furthermore, it was able to detect the polarization of the CMB with high precision, even in regions with low signal intensity.

This opens up new possibilities for studying the CMB, including studying the early stages of the Universe and dark matter, which could benefit several subfields of astronomy and astrophysics.

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Source: Olhar Digital