Compared to the life expectancy of stars, human lives are pretty short. Stars such as Betelgeuse (in Orion) live for millions of years. Others exist for billions of years. We (if were fortunate) get maybe 100 years (basically). To us, stars do not appear to alter much over our lifetimes, unless they blow up as supernovae. However, what about throughout 20 or 30 successive lifetimes?
Orions Belt can be plainly seen, as well as Betelgeuse (red star in the upper left corner). Astronomers of early antiquity saw this star as white-yellow.
Qian wasnt the only skywatcher to tape-record this stars color. Almost 2 thousand years later, around 2 A.D., astronomer Claudius Ptolemy noted it was a “bright, reddish star”. By the 16th century, astronomer Tycho Brahe kept in mind that the star was redder even than Aldebaran (in Taurus).
Well, it turns Betelgeuse did experience apparent modifications in that period of time– and really noticeably so. Betelgeuse has been tracked for thousands of years (as we reported previously this year). In the year 1800 B.C.E., an astronomer in China called Sima Qian, observed that Betelgeuse was a rich, yellow-colored color.
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Changing Colors Indicates Internal Change
“The really truth that it altered in color within 2 centuries from yellow-orange to red tells us, together with theoretical estimations, that it has 14 times the mass of our Sun– and the mass is the primary specification defining the evolution of stars,” he said. “Betelgeuse is now 14 million years old and in its late evolutionary phases.
Neuhäuser and colleagues studied the historic records for star observations of a number of stars. For Betelgeuse, they wrote, “The color change of Betelgeuse is a brand-new, tight restraint for single-star theoretical evolutionary models (or merger designs).
Color: A Clue to Betelgeuse Aging
As a star like Betelgeuse ages, its brightness, size, and color modification. Basically, when Betelgeuses core ran out of hydrogen, it evolved from a yellow-white star to end up being a red supergiant.
As it aged, Betelgeuse experienced mass loss, and it started to cool. It just took a number of thousand years for it to change color. That suggests this evolution was relatively fast. Generally, they progress from blue-white dwarfs to red supergiants over the course of a few centuries. Betelgeuse did it in two, which shows its mass, and from that, the researchers at Jena could determine its age. So, it now ends up that the color modification seen in the centuries in between Sima Qians observations and Ptolemys (from white to red) is an attribute of that evolution.
History Helps Investigate the Hertzsprung Gap
Does it occur to other stars? The researchers likewise studied other stars to see how their colors altered over human time. It appears to be a much slower-evolving star.
The observable properties (brightness, color, temperature, chemical composition, etc) of Betelgeuse and other stars whose colors have been kept in mind throughout history might offer more insight into the physics at work as these stars progress. Of course, astronomers will need to adjust the historic observations carefully with present-day data.
But, this information should assist pinpoint outstanding masses with even greater precision. As the authors state in their papers conclusions, “This might offer further insight into the physics of outstanding interiors and late advancement of supergiants (and the time left up until they go supernova). The historic color advancement is a new tight restriction on either the single-star evolutionary designs or the Betelgeuse merger designs.”
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Red Giant Betelgeuse was yellow some 2,000 years agoColour advancement of Betelgeuse and Antares over two centuries, stemmed from historic records, as a new constraint on mass and age
Orions Belt can be plainly seen, as well as Betelgeuse (red star in the upper left corner). Nearly two thousand years later on, around 2 A.D., astronomer Claudius Ptolemy noted it was a “brilliant, reddish star”. Neuhäuser and colleagues studied the historical records for star observations of a number of stars. As a star like Betelgeuse ages, its size, brightness, and color modification. Essentially, when Betelgeuses core ran out of hydrogen, it progressed from a yellow-white star to become a red supergiant.