How far away is Proxima Centauri, our nearest neighbouring star?

Measured facts

Catalogue identity

Gaia DR3 5853498713190525696

Aliases

Proxima · GJ 551

Source id

5853498713190525696

Distance

1.302 pc · 4.25 ly

Measured catalogue

Gaia DR3 (ESA/Gaia/DPAC and the Gaia Archive)

Try a two-minute journey to our nearest stellar neighbour

Open the 3D view above and wait for the measured star catalogue to load. Proxima is selected as a point source. Drag to orbit and scroll or pinch outward to reveal the depth of the local star field; Return to Earth brings you home.

Compare the Distance fact with Barnard’s Star in Related destinations. A light-year measures distance, not travel speed. Even light takes about 4.25 years to cross this distance in the Solar System frame. The camera flight is a navigation aid, not a spacecraft timetable.

NASA describes Proxima as a red dwarf too faint for the unaided eye. Nearby does not mean visually bright. COSMOS uses catalogue brightness and a bounded point marker, rather than presenting an invented close-up of its surface.

What COSMOS shows

A nearby Gaia source identified by SIMBAD as Proxima Centauri. Its depth and motion here are derived only from Gaia DR3 astrometry.

COSMOS renders Proxima as a measured point source with G-magnitude-driven brightness and a restrained BP−RP colour. It never draws a stellar disc, because no instrument in this catalogue measures one.

Its depth is the naive reciprocal of high signal-to-noise parallax. That is a deliberate, auditable choice: no zero-point correction and no Bayesian prior are applied, and the limitation is disclosed rather than hidden.

Measured astrometry

Every field below is copied from the shipped Gaia DR3 manifest for the Gaia DR3 high-S/N stellar catalogue inside 100 pc. The catalogue selects sources with parallax S/N of at least 10 and a non-null G magnitude, then stores measured position, colour, motion and the published radial velocity. Naive reciprocal of raw Gaia DR3 parallax for this positive, S/N >= 10 sample. No zero-point correction or Bayesian prior is applied.

Parallax

768.066539 masUncertainty 0.049873 mas; signal-to-noise 15400.5.

Derived distance

1.301971 pc · 4.246 lyNaive reciprocal of the raw positive parallax; no zero-point correction and no Bayesian prior.

Right ascension / declination (ICRS)

217.392321° · -62.676075°Reference epoch J2016.0.

G magnitude

8.9847Used only through the bounded COSMOS brightness transfer, which is not an absolute luminosity estimate.

BP−RP colour index

3.8046Rendered through a restrained display transfer, not converted to a temperature.

Proper motion (μ_α*, μ_δ)

-3781.741 · 769.465 mas/yrμ_α* includes the cos δ factor. Positions are propagated linearly from J2016.0.

Radial velocity

-21.943 km/sIncluded, so all three velocity components are measured.

RUWE

0.971453Gaia renormalised unit weight error, carried as provenance rather than used as a selection cut for this landmark.

Catalogue chunk

core-25pcPart of the 371,766-source measured volume inside 100 pc.

Provenance

Provider

ESA Gaia Archive

Release

Gaia DR3

Licence

Gaia public archive data; follow ESA/Gaia/DPAC acknowledgement and citation guidance for publication.

Attribution

ESA/Gaia/DPAC and the Gaia Archive

Catalogue checked

2026-09-05

Catalogue SHA-256

0069111d383d2d2014a73819b637cefee233ed468309115c267098fe6092706d

Alias cross-identification

https://simbad.u-strasbg.fr/simbad/sim-id?Ident=Proxima+CentauriSIMBAD supplies only the visible common name for this source; the astrometry is Gaia.

Limitations COSMOS discloses

• Astronomic distance is a derived quantity from a truncated parallax, so it is not a direct measurement and it carries the stated parallax uncertainty.
• The rendered point size and colour come from bounded display transfers and must not be read as physical size, luminosity or temperature.
• Motion is propagated linearly from J2016.0. Over decades this approximation degrades, and COSMOS does not extrapolate it indefinitely.
• COSMOS names only a small set of nearby stars. It does not claim these are the nearest stars in existence, only that they are the measured landmarks the catalogue currently renders as destinations.

Sources and further reading

• NASA/Hubble: Proxima Centauri and naked-eye visibility