Astronomy

The pattern of the relative abundances of ions of different atomic or molecular mass (mass-to-charge ratio) within a sample. It frequently refers to the measured relative ...

refractory inclusion

Astronomy; Planetary science

Inclusions, enriched in the rare earths and the other elements mentioned in the definition of refractory, which are identified in rocks petrographically because of their ...

pulsar

Astronomy; Planetary science

Variable radio star having stable, very short (around one second) periods of pulsations. Electrons moving rapidly in a pulsar's magnetic field produce narrow beams of radiation ...

refractory elements

Astronomy; Planetary science

Any chemical element that vaporizes (that is, boils) at high temperatures or condenses from a gas at high temperatures. Examples are calcium (Ca), aluminum (Al), uranium (U), ...