- Tonian (Wikipedia)
The Tonian (from Ancient Greek: τόνος, romanized: tónos, meaning “stretch”) is the first geologic period of the Neoproterozoic Era. It lasted from 1000 to 720 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based on radiometric chronometry. The Tonian is preceded by the Stenian Period of the Mesoproterozoic Era and followed by the Cryogenian.
- Delta Scuti (stars.astro.illinois.edu)
Modest Delta Scuti (in Scutum, the Shield), shining only at 5th magnitude (4.71) in a relatively obscure modern constellation best known for its placement in the Milky Way, stands out as the prototype of one of these, the pulsating “Delta Scuti stars,” of which Caph in Cassiopeia is the brightest.
- Delta Scuti (Wikipedia)
Delta Scuti, Latinized from δ Scuti, is a variable star in the southern constellation Scutum. With an apparent visual magnitude that fluctuates around 4.72, it is the fifth-brightest star in this small and otherwise undistinguished constellation. Analysis of the parallax measurements place this star at a distance of about 199 light-years (61 parsecs) from Earth. It is drifting closer with a radial velocity of −45 km/s.