PV Telescopii variable
Encyclopedia
PV Telescopii variable is a type of variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

 that is established in the General Catalogue of Variable Stars
General Catalogue of Variable Stars
The General Catalogue of Variable Stars is a list of variable stars. Its first edition, containing 10,820 stars, was published in 1948 by the Academy of Sciences of the USSR and edited by B. V. Kukarkin and P. P. Parenago. Second and third editions were published in 1958 and 1968; the fourth...

with the acronym PVTEL. This class of variables are defined as "helium supergiant Bp stars
Ap and Bp star
Ap and Bp stars are peculiar stars of types A and B which show overabundances of some metals, such as strontium, chromium and europium; in addition, larger overabundances are often seen in praseodymium and neodymium...

 with weak hydrogen lines and enhanced lines of He and C". That is, the hydrogen spectral lines of these stars are weaker than normal for a star of stellar class
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

 B, while the lines of helium and carbon are stronger. The prototype for this category is PV Telescopii
PV Telescopii
PV Telescopii is a class B-type supergiant in the constelation Telescopium. It is also the prototype of variable stars called PV Telescopii variables. These are blue supergiants with weak Hydrogen lines and enhanced Helium and Carbon lines. Their variable periods are from a few hours to a few...

 (PV Tel), which undergoes small but complex luminosity variations and radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

fluctuations. The PV Tel stars are extremely hydrogen-deficient compared to other B-class stars and vary in luminosity on time scales ranging from a few hours to several years. As of 2008, there are twelve confirmed PV Tel variables in the General Catalogue of Variable Stars.
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