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Open star cluster

Westerlund 1

Also Wd 1

Open in OuranosCompare its size

One of the most massive young star clusters known in the Milky Way, packed with supergiant and hypergiant stars, hidden behind heavy dust in Ara.

Measured

Distance
12,940 light-years
Size
about 11.2 light-years across (approximate)
Constellation
Ara
Position (J2000)
RA 16h 47m 02s, Dec −45.85°

How far, from the Sun

12,900 light-years. To cross it:

  • Light12,900 years
  • Voyager 1's speed230 million years
  • Driving at 100 km/h140 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 holds some of the largest stars known, including red supergiants and stars classed as yellow hypergiants.
  • It holds a magnetar, CXOU J164710.2-455216.

Where this comes from

  • Gaia DR2 cluster parallax 0.252 ± 0.011 mas (Cantat-Gaudin & Anders 2020, A&A 633, A99)
  • 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.