Lambda Cancri
A blue-white spectroscopic binary in Cancer.
Lambda Cancri is a spectroscopic binary star in the zodiac constellation of Cancer, faintly visible to the naked eye with a combined apparent visual magnitude of +5.93. It is located approximately 569 light-years from the Sun and is drifting further away at a line-of-sight velocity of about +23 km/s. The system lies near the ecliptic, making it subject to lunar occultation.
Quick Facts
- Apparent visual magnitude
- +5.93
- Distance from sun
- approximately 569 ly
- Radial velocity
- +23 km/s
- Spectral type (primary)
- B9.5 V
Facts from the source article.
Nomenclature
The binary's Bayer designation is λ Cancri, Latinised to Lambda Cancri. The components are designated Lambda Cancri A and B according to the Washington Multiplicity Catalog convention, adopted by the International Astronomical Union. The system appears in a lunar station named πιαυτος (piautos) in a Coptic manuscript list; Walter Crum suggested Piautos combines the Coptic determiner pi- with the Greek autos, meaning 'the same, the very one'. The origin of these names is unknown, as the Greeks are not known to have used lunar stations. In 2016, the IAU Working Group on Star Names approved the name Piautos for Lambda Cancri on 1 June 2018, attributing it to the brightest component, Lambda Cancri A. In Chinese, the asterism Beacon Fire includes Lambda Cancri with Psi, Phi1 and 15 Cancri; Lambda Cancri itself is known as a part of that asterism, and from this the name Kwan Wei, meaning 'the bright fire', was given.
Properties
The binary nature was announced in 2016 by K. Gullikson and associates. The primary, Lambda Cancri A, is a B-type main-sequence star of class B9.5 V, about 105 million years old, with a projected rotational velocity of 188 km/s. It has 2.6 solar masses, 3.7 solar radii, and radiates 131 times the Sun's luminosity at an effective temperature not specified. Its close companion, Lambda Cancri B, has 80% of the Sun's mass.
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