M82 X-2

M82 X-2

M82 X-2 glows pink in the X-ray spectrum at the center of Messier 82. M82 X-1 is to its right.[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 09h 55m 51.0s
Declination 69° 40′ 45″
Astrometry
Distance12 million ly
(3.5 million pc)
Other designations
CXOU J095550.9+694044, NuSTAR J095551+6940.8
Database references
SIMBADdata

M82 X-2 is an X-ray pulsar located in the galaxy Messier 82, approximately 12 million light-years from Earth.[2] It is exceptionally luminous, radiating energy equivalent to approximately ten million Suns. This object is part of a binary system: If the pulsar is of an average size, 1.4 M☉, then its companion is at least 5.2 M☉.[3] On average, the pulsar rotates every 1.37 seconds, and revolves around its more massive companion every 2.5 days.[4]

M82 X-2 is an ultraluminous X-ray source (ULX), shining about 100 times brighter than theory suggests something of its mass should be able to. Its brightness is many times higher than the Eddington limit, a basic physics guideline that sets an upper limit on the brightness that an object of a given mass should be able to achieve. Possible explanations for violations of the Eddington limit include geometrical effects arising from the funneling of in-falling material along magnetic field lines.

While M82 X-2 was previously known as an X-ray source, it was not until an observation campaign to study the newly discovered supernova SN 2014J in January 2014 that X-2's true nature was uncovered.[5][6] Scientists looking at data from the NuSTAR spacecraft noticed a pulsing in the X-ray spectrum coming from near the supernova in Messier 82.[2][7] Data from the Chandra and Swift spacecraft was used to verify the NuSTAR findings and provide the necessary spatial resolution to determine the exact source.[3][4] After combining the NuSTAR and Chandra data, scientists were able to discern that M82 X-2 emitted both an X-ray beam and continuous broad X-ray radiation.[1] LXs). In 2023 new NuSTAR data confirmed that it exceeded the Eddington limit.[8][9]

  1. ^ a b Smith et al. 1995, p. 204.
  2. ^ a b Cite error: The named reference llnl20141009 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference nasa20141008a was invoked but never defined (see the help page).
  4. ^ a b Smith et al. 1995, p. 202.
  5. ^ Cite error: The named reference caltech20141008 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference futurity20141009 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference nasa20141008b was invoked but never defined (see the help page).
  8. ^ Bachetti, Matteo; Heida, Marianne; Maccarone, Thomas; Huppenkothen, Daniela; Israel, Gian Luca; Barret, Didier; Brightman, Murray; Brumback, McKinley; Earnshaw, Hannah P.; Forster, Karl; Fürst, Felix; Grefenstette, Brian W.; Harrison, Fiona A.; Jaodand, Amruta D.; Madsen, Kristin K. (1 October 2022). "Orbital Decay in M82 X-2". The Astrophysical Journal. 937 (2): 125. arXiv:2112.00339. Bibcode:2022ApJ...937..125B. doi:10.3847/1538-4357/ac8d67. hdl:2299/25784. ISSN 0004-637X.
  9. ^ "NASA Study Helps Explain Limit-Breaking Ultra-Luminous X-Ray Sources". NASA Jet Propulsion Laboratory (JPL). Retrieved 18 April 2023.