For more than a century, the star HD 140283 has been studied, but only now has its age been estimated: within hundreds of millions of years of the age of the Universe. Delivering a scoop, my Nature article, Nearby star is almost as old as the Universe, details this important new conclusion:
The team then exploited the fact that HD 140283 is in a phase of its life cycle in which it is exhausting the hydrogen at its core. In this phase, the star’s slowly dimming luminosity is a highly sensitive indicator of its age, says Bond. His team calculates that the star is 13.9 billion years old, give or take 700 million years. Taking into account that experimental error, the age does not conflict with the age of the Universe, 13.77 billion years.
The very first generation of stars coalesced from primordial gas, which did not contain appreciable amounts of elements heavier than helium, he notes. That means that as old as HD 140283 is, its chemical composition — which includes a low but non-zero abundance of heavy elements — shows that the star must have formed after the first stellar generation.
Conditions for making the second generation of stars, then, “must have been in place very early”, says Bromm. The very first stars are usually thought to have coalesced a few hundred million years after the Big Bang, he notes. Massive and short lived, they died after only a few million years — exploding in supernovae that heated surrounding gas and seeded it with heavier elements.
The Nature article contains more information about the research and characteristics of early stars.
Recent infrared images taken from the Hubble Space Telescope’s Wide Field Camera 3 are the deepest taken of the Universe, and they reveal several galaxies, including one that is the most distant object we’ve ever found. This galaxy is 13.29 billion light years (4.1 billion parsecs) from Earth and were first visible when the Universe was only 450 million years old (only 4 percent of what it is now). From my recent article in Nature, Galaxy found at record-breaking distance:
When we think of good vibrations, we usually don’t consider the vibrations made by stars. But a recent wave of work in asteroseismology is doing just that to break ground in our understanding of stellar structures. Due to the movement and changing temperatures of surface gas, a star pulses and vibrates. Those pulses and vibrations in the structure of the star provides insight about the star’s internal structure. From my Nature article Kepler’s surprise: The sounds of the stars:
…the vibrations penetrate deep into the stellar interior and become resonating tones that reveal the star’s size, composition and mass. So by watching for the characteristic fluctuations in brightness, says [University of Birmingham, UK, astrophysicist William] Chaplin, “we can literally build up a picture of what the inside of a star looks like”.
Better still, he adds, asteroseismologists are now hauling in the data wholesale. After years of being hampered by Earth’s turbulent atmosphere, which obscures the view of the Universe and has limited asteroseismology to about 20 of the brightest nearby stars, researchers have been astonished by the trove of information coming from a new generation of space observatories. Thanks to the French-led Convection, Rotation and Planetary Transits (COROT) space telescope, launched in 2006, and NASA’s Kepler space telescope, launched in 2009, they can now listen in on hundreds of stars at a time.
“We are in a golden age for the study of stellar structure and evolution,” says Hans Kjeldsen, an astronomer at Aarhus University in Denmark.