VY Canis Majoris
VY Canis Majoris — a red hypergiant in Canis Major roughly 3,900 light-years away and one of the largest stars known: about 1,400 times the Sun's radius (near-infrared interferometry; Wittkowski et al. 2012), so vast that in the Sun's place its surface would reach out past the orbit of Jupiter. It is shedding its outer layers in violent, uneven eruptions, wrapped in a lopsided nebula of its own ejected gas and dust — yet from Earth it is a mere 8th-magnitude point, far too faint for the naked eye.
Key facts
Science
Physical
- Mass
- 3.38 × 10³¹ kg · 17 M☉
- Radius
- 6.6 AU · 1,420× wider than the Sun
- Density
- 0.00000837 kg/m³ · 8.4e-09× water
- Spectral type
- M3–M4.5 Ia (oxygen-rich red hypergiant)
Composition
- By mass
- A cool, extremely luminous oxygen-rich red hypergiant about 1,400 times the Sun's radius (Wittkowski et al. 2012) — among the largest stars known. Its surface is so tenuous and unstable that it drives episodic, directed outbursts, building the clumpy, asymmetric nebula of gas and dust that surrounds it. Both its size and its energy output carry tens-of-percent uncertainty (a later analysis, Davies & Beasor 2020, revised its luminosity downward); its distance comes from maser astrometry (Zhang et al. 2012). It will end as a supernova.
Temperature
- Surface
- 3,490 K (3217 °C)
Radiation & temperature
- Surface temperature
- 3,490 K (3217 °C)
- Peak wavelength
- 830 nm · near-infrared (mostly invisible to the eye)
Discovery & history
- Name
- VY Canis Majoris — the variable-star designation 'VY' in Canis Major, the Greater Dog.
Catalogued as a 7th-magnitude star by Jérôme Lalande in 1801. Hubble (WFPC2) and later the VLT's SPHERE imaged the star's asymmetric nebula and dusty knots directly, tracing centuries of episodic, explosive mass loss as it nears the end of its life and an eventual supernova.
Images
Images from open archives · credit shown per image