The eleventh letter of the Greek alphabet.
In lower case, λ, it denotes → wavelength.
It is also used in the → Bayer designation system
to identify a specific star in a → constellation.
See also → lambda point.
From Phoenician lamedh.
Lambda Bootis star
setâre-ye lâmbda Gâvrân
Fr.: étoile lambda du Bouvier
The prototype of a small class of stars (A-F types) which have weak metallic lines (indicating that they are depleted in metals heavier than Si, but with solar abundances of C, N, O, and S). Moreover, they have moderately large rotational velocities and small space velocities. Lambda Boo stars may be pre-main-sequence objects, or they may be main sequence stars that formed from gas whose metal atoms had been absorbed by interstellar dust.
Named after the prototype, the star → Lambda (λ) of constellation → Bootes; → star.
lambda cold dark matter model
Fr.: modèle ΛCDM
The → standard model of → Big Bang that incorporates both → dark matter and → dark energy. See also → cold dark matter (CDM).
→ lambda, → cosmological constant; → cold; → dark; → matter; → model.
Fr.: Lambda (λ) Orionis
Same as → Meissa.
Lambda (λ), a Greek letter used in the → Bayer designation of star names.
Fr.: point lambda
The temperature (roughly 2.17 K) at which → liquid helium (→ helium I) becomes → superfluid (→ helium II).
The name was given by the Dutch physicist Willem Hendrik Keesom (1876-1956), who discovered the behavior of helium near this transition point and successfully solidified helium in 1926 (under an external pressure of 25 atmospheres). The name was originally suggested by Paul Ehrenfest (1880-1933), who was inspired by the shape of the → specific heat curve, which resembles the Gk. letter → lambda; → point.
Shaula (Lambda Scorpii)
Fr.: Shaula, λ Scorpii
The second brightest star in the constellation → Scorpius, lying at a distance of 570 → light-years. With → Lesath (Upsilon Scorpii) both stars make up the Scorpion's stinger. Shaula is a → multiple star with three visible → components. The first one, Lambda Scorpii A, is classified as a B2 IV → subgiant. The 15th magnitude Lambda Scorpii B has a separation of 42 arcseconds from component A, while the 12th magnitude Lambda Scorpii C is 95 arcseconds from A. It is not known whether or not these components are physically associated with component A. The component A is actually a → triple system consisting of two → B-type stars and a → pre-main sequence star.
Shaula, from Ar. ash-shaulah (