Open AccessWhat is the nature of RX J0720.4–3125?
Author(s) -
Heyl Jeremy S.,
Hernquist Lars
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01799.x
Subject(s) - physics , black body radiation , rosat , astrophysics , neutron star , sky , astronomy , radiation , optics , galaxy
RX J0720.4–3125 has recently been identified as a pulsating soft X‐ray source in the ROSAT all‐sky survey with a period of 8.391 s. Its spectrum is well characterized by a blackbody with a temperature of 8 × 10 5 K. We propose that the radiation from this object is thermal emission from a cooling neutron star. For this blackbody temperature we can obtain a robust estimate of the object's age of ∼ 3 × 10 5 yr, yielding a polar field ∼ 10 14 G for magnetic dipole spin‐down and a value of P compatible with current observations.