Binary star systems—two stars gravitationally bound and circling a shared center—are far from unusual, with over half the stars in our galaxy belonging to such pairs or multi-star groups.
Diverse Duos with Dramatic Interactions
These stellar duos often differ significantly in mass, luminosity, and size, and the gravitational dynamics between them can profoundly influence their life cycles. In many cases, one star can siphon matter from its companion, sometimes triggering spectacular phenomena like novae or even supernovae.
Exploring binary systems is crucial to advancing our knowledge of stellar evolution and the behavior of matter under extreme conditions.
A research group from China has recently identified an exceptionally rare pulsar within a binary system, one whose energy pulses are periodically obscured by its stellar partner every few hours. The study, led by Han Jinlin from the National Astronomical Observatories of China, was published in the journal Science.
What Are Pulsars and Why They Fascinate Scientists
Astronomers have identified around 3,500 pulsars in our galaxy, and they find these objects fascinating. Massive stars leave behind these compact remnants when they end their lives in supernova explosions.
They emit focused beams of radiation from their magnetic poles, and as they spin, these beams sweep across space. When Earth lies in the path of a beam, we observe regular bursts of radio, X-ray, or gamma radiation.
The Five-hundred-meter Aperture Spherical Radio Telescope (FAST), nicknamed the “China Sky Eye,” enabled the discovery. As the world’s largest single-dish radio telescope, FAST is located in a karst valley in Guizhou Province and features over 4,400 movable panels forming its immense 500-meter dish, enabling it to detect faint signals from the depths of the cosmos.
FAST’s Mission and Global Collaboration
FAST officially commenced operations in January 2020 and began accepting international research proposals in March 2021. Its mission includes investigating pulsars, fast radio bursts, neutral hydrogen, and searching for signs of extraterrestrial life.
The newly identified system, PSR J1928+1815, lies 455 light-years from Earth and offers an extraordinary look into how binary systems evolve—especially into how a neutron star or pulsar can form alongside a companion.
In such systems, the more massive star reaches the end of its life more quickly, collapsing into a neutron star or black hole. Its lighter companion may then lose material to the denser object, creating a shared gaseous envelope of hydrogen around both.
For a brief period—just as observed with PSR J1928+1815—the two stars orbit within this common envelope. Over roughly a millennium, the neutron star pushes away the surrounding gas, leaving behind a hot, helium-fusing star in orbit around it.
The Brief Phase of Enveloped Orbiting
This rare find provides strong evidence for long-held theories about mass exchange, orbital tightening, and envelope ejection in binary systems. Observations like these deepen our understanding of how stars evolve, how neutron stars behave, and how these binaries might eventually merge—producing gravitational waves detectable across the universe.
Thanks to cutting-edge observatories like FAST, astronomers are optimistic about uncovering more of these elusive stellar pairs and further unraveling the mysteries of our cosmos.
Read the original article on: Science Alert
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