Lambda Velorum apparent magnitudes +2.14 to +2.30. λ Velorum is an evolved star that has exhausted the hydrogen in its core region. It has about seven times the mass of the Sun. It is likely to be on or approaching the asymptotic giant branch (AGB), although its properties do not exclude it being a slightly more massive star on the red giant branch (RGB). As an AGB star it has an inert core of carbon and oxygen and is alternately fusing helium and hydrogen in two shells outside the core. The star's outer envelope has expanded to form a deep, convective, hydrogen
Hydrogen-deficient star Hydrogen-deficient star A hydrogen-deficient star is a type of star that has little or no hydrogen in its atmosphere. Hydrogen deficiency is unusual in a star, as hydrogen is typically the most common element in a stellar atmosphere. Despite being rare, there are a variety of star types that display a hydrogen deficiency. Hydrogen-deficient stars had been noted prior to the discovery of their hydrogen deficiency. In 1797, Edward Pigott noted the profound variation in stellar magnitude of R Coronae Borealis (R CrB). In 1867, Charles Wolf and Georges Rayet discovered unusual emission line structure in Wolf-Rayet stars. Hydrogen deficiency