variable star tagged posts

One of the brightest stars in the night sky, Betelgeuse, may not be on the brink of exploding as a supernova, according to a new study of the star’s brightening and dimming. Instead, recent research shows that the observed pulsing of the starlight is probably caused by an unseen companion star orbiting Betelgeuse.

Formally named Alpha Ori B, the “Betelbuddy” (as astrophysicist Jared Goldberg calls it) acts like a snowplow as it orbits Betelgeuse, pushing light-blocking dust out of the way and temporarily making Betelgeuse seem brighter. Goldberg and his colleagues present their simulations of this process in a paper accepted for publication in The Astrophysical Journal. The findings are published on the arXiv preprint server.

“We ruled out e...

IC 63 — nicknamed the Ghost Nebula — is about 550 light-years from Earth. The nebula is classified as both a reflection nebula — as it is reflecting the light of a nearby star — and as an emission nebula — as it releases hydrogen-alpha radiation. Both effects are caused by the gigantic star Gamma Cassiopeiae. The radiation of this star is also slowly causing the nebula to dissipate.
Credit: ESA/Hubble, NASA

About 550 light-years away in the constellation of Cassiopeia lies IC 63, a stunning and slightly eerie nebula. Also known as the ghost of Cassiopeia, IC 63 is being shaped by radiation from a nearby unpredictably variable star, Gamma Cassiopeiae, which is slowly eroding away the ghostly cloud of dust and gas...

This image, captured with the OmegaCAM camera on ESO’s VLT Survey Telescope in Chile, shows an unusually clean small galaxy. IC 1613 contains very little cosmic dust, allowing astronomers to explore its contents with great clarity. Credit: ESO

German astronomer Max Wolf discovered IC 1613’s faint glow in 1906. In 1928, his compatriot Walter Baade used the more powerful 2.5m telescope at the Mount Wilson Observatory in CA to successfully make out its individual stars. From these observations, astronomers figured out the galaxy must be quite close to the Milky Way, as it is only possible to resolve single pinprick-like stars in the very nearest galaxies to us.
Astronomers have since confirmed that IC 1613 is indeed a member of the Local Group, a collection of more than 50 galaxies that inclu...