if the universe is 13.8 billion years old, how can the Methuselah star be more than 14 billion years old?
For over 100 years, astronomers have been observing a curious star located some 190 light-years away from Earth in the Libra constellation. It rapidly journeys across the sky at 1.3 million kilometers per hour. But more interesting than that, Methuselah (HD 140283) as it is commonly known — is also one of the oldest known stars in the universe. Here are some unbelievable facts about the Methuselah star, one of the oldest stars known.
The estimated age of the star
A study published in 2013 determined the estimated age of the Methuselah star to be 14.46 billion years. At the time, Methuselah was the oldest star known. The study used the Hubble Space Telescope’s Fine Guidance Sensors to measure a trigonometric parallax of 17.15 milliarcseconds for the star and used the precise distance to determine the star’s age. Earlier estimates were even higher, providing an age of 16 billion years.
Is Methuselah older than the universe?
Even though the estimated age of Methuselah (14.46 ± 0.8 billion years) is higher than the age of the universe (13.787 ± 0.020 billion years), the star cannot be older because it could not have formed before the Big Bang. With a margin of error of 0.8 billion years, the star may be as young as 13.66 billion years, which does not conflict with the age of the universe. However, Methuselah must have formed shortly after the Big Bang. Another study conducted in 2014 updated the star’s age to 14.27 ± 0.38 billion years.
How was the star born?
The Methuselah star, which is now growing into a red giant, was born in a dwarf galaxy that the nascent Milky Way ate up more than 12 billion years ago, as concluded by the researchers. The star’s long, looping orbit is likely a residue of that climactic act of star eating itself.
What is the type of the Methuselah star?
Methuselah is a yellow subgiant star and is 2.04 times larger than the Sun and 4.82 times more luminous. The star has an estimated mass of 0.780 or 0.805 solar masses and a surface temperature of 5,787 K. It is a slow spinner. It is one of the most metal-poor (and therefore oldest) stars ever discovered.
Location of Methuselah
Methuselah lies in the region of the sky between Zeta Ophiuchi in the constellation Ophiuchus and Zubeneschamali, the brightest star in Libra. With an apparent magnitude of 7.205, the star requires binoculars to be seen.
Note that the ideal time of year to observe the stars and deep-sky objects in Libra is during June when the constellation climbs high above the horizon in the evening sky.
