The white dwarf observed by the team is understood to be accreting, or feeding, from an orbiting buddy star.
With the new observations, astronomers saw it lose brightness in 30 minutes, a process only previously seen to occur in accreting white overshadows over a duration of a number of days to months.
The brightness of an accreting white dwarf is affected by the amount of surrounding material it eats so the researchers state something is disrupting its food supply.
They hope the discovery will assist them discover more about the physics behind accretion– where items like black holes, white dwarfs, and neutron stars feed upon surrounding product from neighboring stars.
The findings are released in the journal Nature Astronomy.
TW Pictoris is a fairly intense double star where a white dwarf accretes material from a companion star. Observations with the Transiting Exoplanet Survey Satellite (TESS) have revealed how TW Pictoris all of a sudden and abruptly fades in less than 30 minutes. The figure reveals how the TESS observations reveal this shift from a bright mode marked in blue, to a faint mode marked in red. Credit: Simone Scaringi
The team observed the phenomenon in the white dwarf binary system, TW Pictoris, which is discovered about 1,400 light years from Earth.
TW Pictoris consists of a white dwarf that feeds from a surrounding accretion disc sustained by hydrogen and helium from its smaller buddy star. As the white dwarf consumes– or accretes– it becomes brighter.
Using the exact observational detail offered by TESS– normally utilized to search for worlds outside our solar system– the Durham-led team saw abrupt falls and rises in brightness never before seen in an accreting white dwarf on such short timescales.
Because the flow of material onto the white dwarfs accretion disc from its companion star is relatively continuous it must not significantly affect its luminosity on such brief timescales.
Instead, the researchers think what they are experiencing could be reconfigurations of the white dwarfs surface magnetic field.
The totally incorporated Transiting Exoplanet Survey Satellite (TESS), which released in 2018 to discover countless new worlds orbiting other stars. Researchers led by Durham University, UK, utilized TESS to observe the white dwarf double star TW Pictoris. Credit: Orbital ATK/ NASA
During the “on” mode, when the brightness is high, the white dwarf feeds off the accretion disc as it generally would. Suddenly and quickly the system turns “off” and its brightness plunges.
The researchers say that when this happens the magnetic field is spinning so quickly that a centrifugal barrier stops the fuel from the accretion disc from continuously falling onto the white dwarf.
NASAs Transiting Exoplanet Survey Satellite (TESS) is moved inside the Payload Hazardous Servicing Facility at the firms Kennedy Space Center in Florida. Credit: NASA/Frankie Martin
During this stage, the quantity of fuel the white dwarf has the ability to eat is being regulated through a procedure called magnetic gating.
In this case, the spinning electromagnetic field of the white dwarf manages the fuel travelling through a “gate” onto the accretion disc, resulting in semi-regular little boosts in brightness seen by the astronomers.
After some time, the system sporadically turns “on” again, and the brightness increases back to its initial level.
Lead author Dr. Simone Scaringi, in the Centre for Extragalactic Astronomy, at Durham University, UK, said: “The brightness variations seen in accreting white overshadows are generally fairly sluggish, taking place on timescales of days to months.
” To see the brightness of TW Pictoris plunge in 30 minutes is in itself extraordinary as it has actually never ever been seen in other accreting white overshadows and is totally unexpected from our understanding of how these systems are supposed to feed through the accretion disc. It appears to be changing on and off.
” This truly is a formerly unacknowledged phenomenon and because we can draw contrasts with comparable habits in the much smaller sized neutron stars it might be a crucial step in assisting us to much better comprehend the process of how other accreting things feed upon the material that surrounds them and the important function of magnetic fields in this process.”
As white dwarfs are more common in the Universe than neutron stars, the astronomers intend to look for other examples of this behavior in future research tasks for more information about accretion.
Referral: “An accreting white dwarf showing quick transitional mode changing” 18 October 2021, Nature Astronomy.DOI: 10.1038/ s41550-021-01494-x.
The research was funded in the UK by Durham University. The research group also consisted of the Italian National Institute for Astrophysics, the South African Astronomical Observatory, the University of Cape Town and the University of the Free State, both also South Africa, Radboud University, The Netherlands, the University of Southampton, UK, and the University of Notre Dame, USA.
TW Pictoris is a reasonably bright binary system where a white dwarf accretes product from a companion star. Observations with the Transiting Exoplanet Survey Satellite (TESS) have revealed how TW Pictoris all of a sudden and abruptly fades in less than 30 minutes. The figure shows how the TESS observations expose this shift from a bright mode marked in blue, to a faint mode marked in red. The completely integrated Transiting Exoplanet Survey Satellite (TESS), which introduced in 2018 to discover thousands of brand-new worlds orbiting other stars. Researchers led by Durham University, UK, utilized TESS to observe the white dwarf binary system TW Pictoris.
An artists impression example of a white dwarf– in this image the white dwarf MV Lyrae– accreting as it draws in product from a companion star. Credit: Helena Uthas
Astronomers have actually used a planet-hunting satellite to see a white dwarf quickly turning on and off for the first time.
The scientists led by Durham University, UK, used NASAs Transiting Exoplanet Survey Satellite (TESS) to observe the unique phenomenon.
White dwarfs are what a lot of stars become after they have burned off the hydrogen that fuels them. They are roughly the size of the Earth, however have a mass more detailed to that of the Sun.
