Astronomers Develop First 3-D Map of Milky Way

Comparison of simulation of three main star forming episodes in the spiral arms with the currently observed Cepheid variables. Oldest stars (red) are 400 million years old and the youngest (blue) are 30 million years old. Top view of the Milky Way, simulations are shown in the left panel, observations – in the right panel. (J. Skowron / OGLE / Astronomical Observatory, University of Warsaw)

(CN) – The Milky Way galaxy is home to countless stars, planets, and other celestial objects. Currently, scientists’ knowledge of its shape is based on what is known about other galaxies and models of our own solar system – but it is not the whole picture.

Astronomers Dorota Skowron and her colleagues from the University of Warsaw used a much more accurate means of gathering this information. In their study published Thursday in the journal Science, they showed that by measuring the distance between classical Cepheid variable stars within the galaxy, they could develop a three-dimensional map of the Milky Way in unprecedented detail.

Cepheid variables are different from ordinary stars, and have been used in the past as markers to measure distances of up to millions of light-years. The Hubble Telescope recently used these stars to determine the distance to a galaxy in the Virgo cluster, 56 million light-years from Earth. The Cepheid variable stars are useful because they pulsate at a constant rate of luminosity similar to a lighthouse, allowing astronomers to determine their distance from another object.

Thanks to a project named the Optical Gravitational Lensing Experiment (OGLE), scientists have identified more than double the number of classical Cepheid variables previously known. Skowron and her colleagues charted the distances of more than 2,400 Cepheid variables and determined their coordinates relative to the sun. Using this mapping approach, they re-examined what is known about the Milky Way’s physical features.

The Milky Way is classified as a barred spiral galaxy, giving it an S-like shape. From a frontal view, it has four primary arms branching out of a central bar and from a side view it appears to be a thin band of gas, dust, and stars emitting a milky light, hence its name. Skowron and the team found it is not flat like a disk, but rather warped and twisted – a feature previously detected but never before seen in this way.

With this new information and cutting-edge three-dimensional map of the Milky Way galaxy, Skowron and the team have opened doors to understanding more about the supermassive cluster of stars we call home.

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