Przybylski's Star


Przybylski's Star, or HD 101065, is a rapidly oscillating Ap star at roughly from the Sun in the southern constellation of Centaurus.

Scientific history

In 1961, the Polish-Australian astronomer Antoni Przybylski discovered that this star had a peculiar spectrum that would not fit into the standard framework for stellar classification. Przybylski's observations indicated unusually low amounts of iron and nickel in the star's spectrum, but higher amounts of unusual elements like strontium, holmium, niobium, scandium, yttrium, caesium, neodymium, praseodymium, thorium, ytterbium, and uranium. In fact, at first Przybylski doubted that iron was present in the spectrum at all. Modern work shows that the iron-group elements are somewhat below normal in abundance, but it is clear that the lanthanides and other exotic elements are highly overabundant.
Przybylski's Star also contains many different short-lived actinide elements with actinium, protactinium, neptunium, plutonium, americium, curium, berkelium, californium, and einsteinium being detected. The longest-lived isotope of einsteinium has a half-life of only 472 days. Other radioactive elements discovered in this star include technetium and promethium.
Compared to neighboring stars, HD 101065 has a high peculiar velocity of.

Theories

Because of the odd properties of this star, there are numerous theories about why the oddities occur. One such theory is that the star contains some long-lived nuclides from the island of stability and that the observed short-lived actinides are the daughters of these progenitors, occurring in secular equilibrium with their parents.

Properties

HD 101065 is the prototype star of the rapidly oscillating Ap star variable star class. In 1978, it was discovered to pulsate photometrically with a period of 12.15 min.
A potential companion had also been detected, a 14th magnitude star 8 arc seconds away. This would be a separation of nearly 1,000 AU. However, Gaia Data Release 2 suggests that this star lies at a distance from us of light-years, more than twice the distance of Przybylski's Star.