2024-01-10 05:15:35
RW Cephei, located about 16,000 light-years from Earth, is a gigantic star. If we placed it with its center where the Sun is, its outer edge would reach beyond the orbit of Jupiter. RW Cephei is near the end of his life as a working star. It is in the red giant stage, a phase in which stars swell, significantly increasing their diameter. In the case of stars like RW Cephei, rather than red giants, they are red hypergiants.
A year ago, RW Cephei experienced a strange and noticeable decrease in brightness.
As a result, a research team monitored the star’s brightness.
The team was led by Narsireddy Anugu of the CHARA interferometer, a set of six optical telescopes from Georgia State University located at the Mount Wilson Astronomical Observatory, California, United States.
The six telescopes that make up the CHARA interferometer are spread across the top of Mount Wilson to act together as one enormous telescope. The combination of its light beams gives the CHARA Interferometric Array the ability to see details of very tiny objects in the sky, about 30 times smaller than the smallest ones that can be seen with the largest conventional telescopes, and smaller than a being. human on the Moon seen from Earth.
Stars that are in the stage that RW Cephei is now experiencing show light variations that are related to changes in their outer layers. The changes are usually small, so when in December 2022, the brightness of RW Cephei had faded to about a third of its normal brightness, an unprecedented drop, the surprise in the astronomical community was capital.
Images of RW Cephei captured by the CHARA telescope array in December 2022 (left) and July 2023 (right) and processed in false colors. In December 2022, the brightness was the lowest on record. In July 2023, the brightness had already increased again. (Photos: Georgia State University / The CHARA Array)
The observations made during the monitoring of RW Cephei, as well as a thorough analysis carried out with the help of intelligent algorithms created by the research team, have made it possible to find the most plausible explanation.
Everything indicates that a large eruption, much of it in the direction of Earth, released a cloud of gas from RW Cephei, and that cloud, like fog, blocked a large fraction of the starlight. Specifically, as the cloud moved away, it cooled and created swarms of dust particles that effectively blocked a large percentage of the starlight. With the progressive expansion of the cloud, it has become less thick and the starlight observable from Earth has increased again.
The study is titled “The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis.” It was published in the academic journal The Astronomical Journal, and has also been presented at the latest congress of the American Astronomical Society, held in New Orleans, United States. (Source: NCYT from Amazings)
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