Largest Stars in the Milky Way

Data

Note: What You Should Know About the Largest Stars in the Milky Way

Not every "huge" star you've heard about actually tops the list — and that's one of the most fun things about astronomy. This page ranks the largest known stars by solar radius (R☉), and the current record-holder in the Milky Way is RSGC1-F01 at about 1,530 R☉, which means its radius is roughly 1,530 times that of the Sun. For contrast, VY Canis Majoris sits at about 1,420 R☉, and VX Sagittarii comes in around 1,500 R☉. All of these monsters are red supergiants or red hypergiants.

What Does "1,530 Solar Radii" Actually Mean?

• Scale: The Sun's radius is about 696,000 km. At 1,530 R☉, RSGC1-F01 sprawls across roughly a billion kilometers — more than 10 times the distance from Earth to the Sun.
• What fits inside: If you swapped this star for the Sun, it would easily swallow the orbit of Jupiter — and then some. The gigantic volume is why astronomers call them supergiants rather than ordinary giants.
• Low density: Despite their bulk, these stars are surprisingly diffuse — the "atmosphere" out to that radius is thin and tenuous compared to the dense core.

Why Are They So Huge?

• Late-life expansion: Massive stars burn through their core hydrogen fast, then puff outward into red supergiants as heavier elements take over fusion.
• Fragile balance: Their outer layers are held up by the balance between outward radiation pressure and gravity — a delicate state that makes them prone to violent pulsations.
• Matter loss: They throw off enormous amounts of material as stellar winds. VY Canis Majoris, for instance, is losing mass at an astonishing rate, blasting dust and gas out into space.

They're Rare and Short-Lived

• Rarity: There are hundreds of billions of stars in the Milky Way, yet only a handful are true red supergiants this large — the table lists 18, and the very top few are all found in or near the RSGC1 star cluster toward the galactic center.
• Short lives: A star this massive might last only a few million years before exploding — a blink of an eye next to the Sun's expected 10 billion years.
• Fate: Most will end in a spectacular core-collapse supernova, leaving behind a neutron star or black hole. Some may even collapse straight to a black hole without a visible blast.

Star-Spotting Tips

• Cygnus is a goldmine: BC Cygni, KY Cygni, and RW Cygni all live in the constellation Cygnus — a great region to photograph with long-exposure imaging even if you can't see them by eye.
• Variable behavior: Many of these stars pulse and dim unpredictably. RW Cephei had a famous dimming event in 2022, reminding us that these giants are never quite steady.
• Binaries: VV Cephei A is part of an eclipsing binary system, so it periodically dips in brightness as its companion passes in front — a fun object to chart over weeks.

Fun Facts

• Not in the top 5 here: Everyone knows UY Scuti and Betelgeuse, but neither tops this particular Milky Way list — the biggest here beats them on the solar-radius scale used for this ranking.
• The Sun is a dwarf by comparison: If our Sun sat next to RSGC1-F01, it would look like a tiny speck, invisible against the giant's glare.
• Cluster superiority: Three of the top four spots (RSGC1-F01, RSGC1-F04, and RSGC1-F06) belong to the same cluster — RSGC1 is clearly a nursery of extremes.

In short: the largest stars in the Milky Way are dramatic, fragile, brilliant monsters born in dense star clusters — and they're living on borrowed time. Sizes here can shift as measurements improve, so think of these radii as "best current estimate" rather than the final word.