The mass and radius of the neutron star in 4U 1820-30

Tolga Güver, Patricia Wroblewski, Larry Camarota, Feryal Özel

Research output: Contribution to journalArticlepeer-review

213 Scopus citations


We report on the measurement of the mass and radius of the neutron star in the low-mass X-ray binary 4U 1820-30. The analysis of the spectroscopic data on multiple thermonuclear bursts yields well-constrained values for the apparent emitting area and the Eddington flux, both of which depend in a distinct way on the mass and radius of the neutron star. The distance to the source is that of the globular cluster NGC 6624, where the source resides. Combining these measurements, we uniquely determine the probability density over the stellar mass and radius. We find the mass to be M = 1.58 ± 0.06 M and the radius to be R = 9.1 ± 0.4 km.

Original languageEnglish (US)
Pages (from-to)1807-1812
Number of pages6
JournalAstrophysical Journal
Issue number2
StatePublished - Aug 20 2010


  • Stars: individual (4U 1820-30)
  • Stars: neutron
  • X-rays: binaries

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The mass and radius of the neutron star in 4U 1820-30'. Together they form a unique fingerprint.

Cite this