Sirius A
Sirius A is the brighter main-sequence star in the Sirius binary system.
How big is it?
2,379,000 km across
Diameter · rounded model
A little perspective
Sirius A vs Sun: diameter comparison
The diameter of Sirius A is about 1.71 times the diameter of the Sun.
Sirius A is the brighter main-sequence star in the Sirius binary system.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
Measurements, assumptions & sources +
Sirius A
Diameter: 2,379,000 km; rounded model.
A rounded main-sequence star model for the brighter member of Sirius.
Defined examples — our methodology
The marked diameter is calibrated. Unmeasured illustration details are representative.
Sun
Diameter: 1,391,000 km; approximate.
Our star, modelled with the IAU nominal solar radius. “Surface” means the visible photosphere. The core is much hotter; this is not a solid surface.
IAU — nominal solar and planetary conversion constants
The marked diameter is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 2,379,000 km
We compare the diameter of Sirius A. This is an illustrative comparison value, not a claim that every example is the same.
A rounded main-sequence star model for the brighter member of Sirius.
The marked horizontal span follows the measured feature, not the edges of the image. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 2,379,000 km | Not recorded | rounded model | |
| 2.06 M☉ | Not recorded | rounded model |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
SpaceSun1,391,000 kmThe Sun is the star at the centre of the Solar System.
SpaceJupiter139,800 kmJupiter is a giant planet composed mainly of hydrogen and helium, orbiting the Sun beyond the asteroid belt.
SpaceNeutron star20 kmA neutron star is the dense remnant core left after a massive star explodes as a supernova, composed mostly of neutrons.
SpaceEarth–Moon distance384,400 kmThe Earth–Moon distance is the average space between the centres of the Earth and the Moon.
SpaceProxima Centauri214,300 kmProxima Centauri is a red dwarf star and the closest known star to the Sun.
SpaceSaturn116,500 kmSaturn is a giant planet made mostly of hydrogen and helium, distinguished by its extensive ring system.SpaceRed giant0.465 AUA red giant is a star that has expanded and cooled after exhausting the hydrogen in its core.
SpaceUranus50,720 kmUranus is an ice giant planet with a blue-green atmosphere, orbiting the Sun on its side.