Betacoronavirus the Latin “corona” meaning crown or halo, referring to their image under electron microscopy of crown-like spikes on their surface similar to the solar corona. This morphology is created by the viral spike (S) peplomers, which are proteins that populate the surface of the virus and determine host tropism. The order Nidovirales is named for the Latin nidus, which means nest. It refers to this order’s production of a 3' co-terminal nested set of subgenomic mRNA's during infection. Betacoronavirus Betacoronaviruses are one of four genera of coronaviruses of the subfamily "Coronavirinae" in the family "Coronaviridae", of the order "Nidovirales". They
Stellar halo dominated by stars which formed within the galaxy, and an outer region primarily composed of stars accreted through merger events. Predictions for these components include different structure and rotation directions. Observational evidence for this dual halo in the Milky Way has been claimed but contested. Studies of the Milky Way galaxy have found that approximately 0.1-1% of its total stellar mass is contained within the stellar halo, and that it extends to over 100 kiloparsecs from the galactic centre. Stellar halo The stellar halo of a galaxy refers to the component of its galactic halo containing stars. The halo extends