Astronomers have spotted four dead white dwarf stars playing a game of cosmic hide-and-seek, hidden in the brightness of their four red dwarf companion stars.
This marks the first detection of white dwarfs present in a double star system in our cosmic backyard. white dwarfs All of them lie within about 65 light-years of Earth, and one of them ranks ninth in the top 10 nearest white dwarfs to the Solar System.
White dwarfs are a type of stellar remnants that are left behind when stars rotate around themselves. size of sun ran out of fuel needed for nuclear fusion. Due to this their core starts collapsing. The lack of fusion also means that these stellar remnants cool and become blurry. Thus, the light of very large and bright red dwarf stars is incredibly effective at masking white dwarfs.
“It is usually easy to find isolated white dwarfs nearby, but we could not see these four stars directly in visible wavelengths because their red dwarf companions were blocking their light,” said team leader Mary O’Brien of the University of Warwick in the UK. said in a statement. “It’s a reminder that even in our own cosmic neighborhood, we can still find surprises if we look in the right way, at the right wavelength.”
wobbles gave them
Although astronomers have been diligently surveying our cosmic backyard for decades, white dwarfs are extremely good at remaining invisible. In fact, the only thing that gave away these four hidden dead stars? The wires behind which they were hidden created a strange “wobble” in their motion, as if a hidden child was moving the curtain.
The team followed these telling clues by taking a closer look at these systems with long-term service to NASA Hubble Space Telescope. The investigation was performed in ultraviolet light and used custom calibration to prevent the brightness of the red dwarf companions from mimicking the white dwarf signals.
This investigation not only revealed four mysterious white dwarfs, but also revealed that one of these systems, G 203-47, located just 25 light years away, has some strange features. Twenty-seven years passed between the initial radial wobble and the detection of this hidden dead star.
However, this is not a strange thing. What’s strange is that this white dwarf’s red dwarf companion rotates only once every 100 Earth days, yet it takes only 15 days to orbit its dead star companion. This means that gravitational forces have failed to lock the red dwarf and white dwarf together, which happens in similar systems.
“What is surprising is that G 203-47 should not rotate so slowly if it formed at the same time as similar systems. This suggests that these binaries have had very different evolutionary histories,” said team member David Wilson of the University of Colorado Boulder. “Initially some suffered violent, prolonged interactions, which left them badly off-guard. Others, like G 203-47, experienced softer, brief encounters, which left them in this unusual state.”
The discovery of these white dwarfs helps researchers better understand the population of dead stars throughout the galaxy. In fact, predictions would have suggested finding about four to five closely orbiting white dwarf-red dwarf pairs within about 65 light-years of our Solar System, so finding four should add much more confidence to our current theoretical models.
“Only 30% of red dwarfs within 20 Digvikala [65 light-years] have been systematically surveyed for hidden white dwarf companions,” team member and University of Warwick researcher Pierre-Emmanuel Tremblay said in the statement. “We think there may be nine or 10 additional binary system In our local stellar atmosphere we have not found it yet.
“If we put more targeted effort into observing red dwarfs, perhaps we would find more surprises like this.”
The team’s research was published Tuesday (July 14) in the journal Monthly Notices of the Royal Astronomical Society (MNRAS).
