PSR J2144−3933

PSR J2144−3933 is a pulsar about 180 parsecs (587 light-years) from Earth. It is the coldest known neutron star with a surface temperature less than 42000 Kelvin as measured by the Hubble Space Telescope.^[1] It was previously thought to have a period of 2.84 seconds but is now known to have a period of 8.51 seconds, which is among the longest-known radio pulsar.

PSR J2144−3933

Observation data Epoch J2000      Equinox J2000
Constellation	Grus
Right ascension	21h 44m 12.10s
Declination	−39° 33′ 55.2″
Characteristics
Spectral type	Pulsar
Variable type	None
Astrometry
Distance	approx. 587 ly (approx. 180 pc)
Details
Rotation	8.51 s
Other designations
EUVE J2144-39.6
Database references
SIMBAD	data

J2144−3933 is also notable for other reasons: its mean pulse profile is very narrow in comparison to the pulse period with a half-intensity width of less than one degree of longitude. It also has the lowest spindown luminosity of any pulsar at about 3×10²¹ watts.

Writing in Nature, astrophysicists M. D. Young and coworkers consider this object and suggest that its existence throws current theories into doubt. They state:

Moreover, under the usual model assumptions, based on the neutron-star equations of state, this slowly rotating pulsar should not be emitting a radio beam. Therefore either the model assumptions are wrong, or current theories of radio emission must be revised^[2]

The fact that J2144−3933 is the coldest observed neutron star has been exploited to constrain the properties of dark matter.^[3][4][5]