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Neutron star

Hercules X-1

Also Her X-1 · HZ Herculis

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An X-ray pulsar spinning every 1.24 seconds in a 1.7-day orbit with a companion star.

Measured

Distance
about 28,290 light-years (published estimates 21,530–32,130)
Constellation
Hercules
Position (J2000)
RA 16h 57m 50s, Dec +35.34°

How far, from the Sun

About 28,300 light-years. To cross it:

  • Light28,300 years
  • Voyager 1's speed503 million years
  • Driving at 100 km/h305 billion years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Facts

  • It was one of the first X-ray pulsars found, by the Uhuru satellite in 1971.
  • Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.

Where this comes from

  • Gaia DR3 parallax 0.1153 ± 0.0138 mas (Gaia Collaboration 2023, A&A 674, A1); Reynolds et al. 1997, MNRAS 288, 43 found 6.6 ± 0.4 kpc from the companion
  • This research has made use of the SIMBAD database, CDS, Strasbourg, France (Wenger et al. 2000, A&AS 143, 9).
  • This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI: 10.26093/cds/vizier).

Every catalogue Ouranos draws is credited on the credits page.