31 Crateris is a binary star system in the constellation

Corvus ''Corvus'' is a widely distributed genus of medium-sized to large birds in the family Corvidae. It includes species commonly known as crows, ravens and Rook (bird), rooks. The species commonly encountered in Europe are the carrion crow, the hoo ...

. Varying between apparent magnitudes 5.19 and 5.23 over 1.48 days, it has the variable star designation of TY Corvi. It is actually a remote system with a hot blue-white star of spectral type B1.5V and a companion about which little is known. The two stars orbit each other every 2.9631 days. The primary is possibly a

blue straggler A blue straggler is a main-sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams ...

of the Hyades group. The primary is around 15.5 times as massive as the Sun and 52,262 times as luminous. British astronomer

John Flamsteed John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called ''Atlas Coe ...

numbered the stars in an expanded constellation he termed ''Hydra and Crater'', which included the stars of Hydra immediately below the Cup. Published in 1712, this was not followed by later astronomers. 31 Crateris ended up in the constellation Corvus after formal boundaries were set in 1922. On 27 March 1974, the ''

Mariner 10 ''Mariner 10'' was an American Robotic spacecraft, robotic space probe launched by NASA on 3 November 1973, to fly by the planets Mercury (planet), Mercury and Venus. It was the first spacecraft to perform flybys of multiple planets. ''Ma ...

'' mission detected emissions in the far ultraviolet. These were initially thought to be

Mercury's moon Mercury is the closest planet to the Sun and lacks any natural satellites. An undiscovered moon orbiting the planet was hypothesized to exist in the early 1970s, but it turned out to be misinterpreted data from the star 31 Crateris. Observation of ...

before the source was shown to be 31 Crateris.

References

{{Stars of Corvus B-type main-sequence stars Blue stragglers Crateris, 31 104337 058587 Corvus (constellation) 4590 Durchmusterung objects Spectroscopic binaries Mariner program