Star

Messier 40

Also M40 · Winnecke 4 · WNC 4

Open in Ouranos

A pair of unrelated stars that only look close together; Messier logged it while searching for a nebula reported by Hevelius.

Measured

Distance: about 1,013 light-years (published estimates 471–1,013)
Constellation: Ursa Major
Position (J2000): RA 12h 22m 12s, Dec +58.08°

How far, from the Sun

About 1,010 light-years. To cross it:

Light1,010 years
Voyager 1's speed18 million years
Driving at 100 km/h10.9 billion years

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

Facts

Gaia shows the two stars are at very different distances: about 1,010 and 470 light-years.
It is a chance alignment, not an orbiting pair.

Where this comes from

Gaia DR3 parallaxes 3.2191 ± 0.0118 mas (HD 238107, brighter star) and 6.9328 ± 0.0155 mas (HD 238108, fainter star) (Gaia Collaboration 2023, A&A 674, A1)
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.