NASA astronomers confirmed, using the NuSTAR X-ray telescope, that the neutron star M82
The compact object has a brightness approximately 10 million times that of Sol and exceeds the theoretical ceiling that should prevent the continuous accretion of matter.
Recent research demonstrates that extremely intense magnetic fields and a high rate of mass transfer explain the phenomenon without the need for optical tricks or intermediate-mass black holes.
The discovery reinforces that some ultraluminous X-ray sources are highly magnetized neutron stars.
Characteristics of the M82 X-2 object
The neutron star has a mass greater than the solar one concentrated in a diameter of about 20 kilometers.
Its surface gravity reaches 100 trillion times that of Terra.
The binary system includes a companion star that loses material at a rate equivalent to 1.5 Earth masses per year.
Eddington limit violated
The limit of Eddington establishes the balance between external radiation pressure and internal gravitational force.
Above this level, radiation would expel the gas before reaching the surface.
In M82 X-2, the observed luminosity reaches 10³⁹ erg per second, a value 100 to 500 times greater than expected for a typical neutron star.
Previous studies suggested intermediate-mass black holes as an explanation.
Role of extreme magnetic fields
Magnetic fields above 10¹³ gauss channel matter through narrow funnels along lines of force.
This configuration reduces photon scattering and allows continuous accretion even at high luminosity.
The behavior brings the object closer to the class of magnetars. Modelos Theorists indicate that the accretion disk ends near the radius where magnetic forces dominate.
Orbit and mass transfer measurements
Data collected by NuSTAR over eight years reveals gradual shortening of the orbital period.
The reduction occurs due to the intense transfer of mass and angular momentum.
The measured rate exceeds the classical Eddington limit for accretion by 150 times. Essas observations eliminate hypotheses based solely on directional beam effects.
Implications for ultraluminous sources
M82 X-2 serves as a natural laboratory for extreme conditions unattainable on land.
- Tests interaction between radiation pressure, magnetic fields and gravity
- Aids understanding of the evolution of compact binary systems
- Contributes to the interpretation of gravitational waves detected by LIGO and Virgo
- Suggests that many ULX sources harbor magnetized neutron stars rather than black holes
Future evolution of the system
The orbit will continue to shrink over millions of years.
The donor star will progressively lose mass.
The pair may form a more compact configuration in the future. The process changes the current appearance of the ultraluminous X-ray source.
Context in the galaxy M82
The galaxy Messier 82 has a high rate of star formation. Regiões of stellar birth concentrate several ultraluminous sources.
M82 X-2 is located far from the galactic center.
The environment favors binary systems with high mass transfer.
The study led by Matteo Bachetti, Observatório of Cagliari of Instituto Nacional of Astrofísica of
