Old but still warm: Far-UV detection of PSR B0950+08

Abstract

We report on a Hubble Space Telescope detection of the nearby, old pulsar B0950+08 ($d\simeq 262$ pc, spin-down age 17.5 Myr) in two far-ultraviolet (FUV) bands. We measured the mean flux densities ${\bar{f}}_{\nu }=109\pm 6$ nJy and $83\pm 14$ nJy in the F125LP and F140LP filters (pivot wavelengths 1438 and 1528 Å). Using the FUV data together with previously obtained optical-UV data, we conclude that the optical-FUV spectrum consists of two components -- a nonthermal (presumably magnetospheric) power-law spectrum ($f_{\nu }\propto {\nu }^{\alpha }$) with slope $\alpha \sim -1.2$ and a thermal spectrum emitted from the bulk of the neutron star surface with a temperature in the range of $(1-3)\times 10^5$ K, depending on interstellar extinction and neutron star radius. These temperatures are much higher than predicted by neutron star cooling models for such an old pulsar, which means that some heating mechanisms operate in neutron stars. A plausible mechanism responsible for the high temperature of PSR B0950+08 is the interaction of vortex lines of the faster rotating neutron superfluid with the slower rotating normal matter in the inner neutron star crust (vortex creep heating).

9 pages, 5 figures. Accepted by the Astrophysical Journal

References in corpus (5)

• The ATNF Pulsar Catalogue
• Pulsar Wind Nebulae Created by Fast-Moving Pulsars
• Hubble Space Telescope detection of the millisecond pulsar J2124-3358 and its far-ultraviolet bow shock nebula
• UV emission from young and middle-aged pulsars: Connecting X-rays with the optical
• Optical excess of dim isolated neutron stars

Cited by in corpus (15)

• Thermal luminosities of cooling neutron stars
• Dark Matter Heating vs. Rotochemical Heating in Old Neutron Stars
• Hubble Space Telescope non-detection of PSR J2144-3933: the coldest known neutron star
• Heat blanketing envelopes of neutron stars
• Neutron - mirror neutron mixing and neutron stars
• Smoke and mirrors: Neutron star internal heating constraints on mirror matter
• Capture of Electroweak Multiplet Dark Matter in Neutron Stars
• Searching for New Physics in Ultradense Environment: a Review on Dark Matter Admixed Neutron Stars
• Thermal and nonthermal emission in the optical-UV spectrum of PSR B0950+08
• Hubble Space Telescope observations of the old pulsar PSR J0108-1431
• Timing and Evolution of PSR B0950+08
• Physics of radio emission in the long-period pulsars
• Search of nearby resolved neutron stars among optical sources
• Axion Emission from Proton Cooper Pairs in Neutron Stars
• Neutron star heating vs. HST observations