March 26
The Heart of Charles
Sun Position
The Sun is in Aries at roughly +4° declination; the Northern Hemisphere is accumulating daylight quickly, and the Southern Hemisphere's autumn evenings are arriving earlier each week.
Sky Highlight
Canes Venatici, the hunting dogs, is a faint spring constellation that rides beneath the handle of the Big Dipper and is best placed in March and April evenings from the Northern Hemisphere. It is home to M51 (Whirlpool Galaxy) and M3 (a globular cluster), but its brightest star, Cor Caroli, is itself the main reason to find the constellation.
Deep Sky Object
M3, a globular cluster in Canes Venatici, about 34,000 light-years away, one of the finest globular clusters in the Northern Hemisphere sky; it contains several hundred thousand stars and resolves into individual points in medium telescopes. Visible from both hemispheres but best from the north.
Featured Star
Cor Caroli (α² CVn) is a chemically peculiar A-type star 110 light-years away, spectral class A0pSiEuHg, the prototype of the Alpha-2 Canum Venaticorum class of magnetic variables. Its name means 'heart of Charles,' given to honor King Charles II of England after the Restoration; it has a visual companion about 19 arcseconds away, making it an easy and attractive double.
Around This Date
- March 26, 1859Urbain Le Verrier submitted his analysis of an anomaly in Mercury's perihelion precession to the French Academy of Sciences, a problem that classical mechanics could not explain and that would eventually be resolved by Einstein's general relativity in 1915.
- March 26, 1996Comet Hyakutake made its closest approach to Earth, passing at about 0.10 AU and briefly becoming one of the brightest comets in decades; it was also the first comet detected as an X-ray source, a wholly unexpected discovery made during this apparition.
A magnetically peculiar star named for a king, orbited by a companion easy to split. Cor Caroli is one of those places in the sky where history and physics arrived at the same point.