Displaying items by tag: Variable Star
So named because of its changing light and dark patterns on the nebula is though to be caused by dust clouds near the illuminating source by the star R Monocerotis casting shadows on the nebula. The star itself a T Tauri variable, is encased dense clouds of dust.
The patterns are know to change over weeks and months. Discovered by William Herschel and studied by Edin Hubble.
Quick capture of Nova Sgr 2021 No.2 (V6595 Sgr) from last night. Discovered on April 4th, currently around Mag 8.
Mira or Omicron Ceti is a red giant star in Cetus. Prototype for a class of red giant variable stars that pulsate over periods of 100 to 1,000 days. Mira itself pulsates over 331.65 days going from a magnitude 2.0 down to 10.1. The star also undergoes a helium flash period about every 10,000 years. A white dwarf also is in orbit around Mira at 70 AU, and material lost from Mira is accreated by the white dwarf. Not massive enough to end in a black hole, it will eventually lose its out shells and become a white dwarf itself. As it plows through space, the mass lost forms a comet like tail and shock wave bubble in its direction of travel.
Algol, Beta Persei, sometimes known as the Demon Star was one of the first noticed variable stars, dipping from mag 2.1 to 3.4 every 2 days, 20 hours and 48.8 minutes when a dimmer companion passes in front of it from our viewpoint. Probably noticed by ancient astronomers. It is a multi star system with at least 3 stars in the system. Primary star Beta Persei A is of type B8V, one of the spectroscopic stars B is an orange sub giant of type KOIV, and C is type A7m. The A and B stars are only 0.062 AU apart, while C orbits the pair at 2.69 AU.
7.3 million years ago, Algol came within 9.8 light years of our solar system, it would have shined in the night sky a magnitude brighter than Sirius does today.
It has a very dark reputation in ancient history as a star of death and misfortune.
Ross 248 or HH Andromedae is a red dwarf star currently located in Andromeda. At a distance of 103 light years, it is one of the closer stars. In about 33,000 years it will actually be the closest star for about 9,000 years as it comes with in 3 light years before continuing on. Despite its closeness, it shines only at a magnitude 12.3, so its not visible with out a telescope. As like many red dwarf stars, its also a flare star. No unseen companions have been detected around it so far.
As a closer star, some movement is visible in images taken years apart. This animation shows the movement over a 5 year period.
Barnard's Star is a red dwarf located 6 light years away. At mag 9.5 telescope is needed to see it. It displays the highest motion across the sky (proper motion). It's motion is visible in images taken a year apart. My images from 2014-2020.
Antares is a swollen red supergiant star located in Scorpius the Scorpion. As the brightest star in that constellation it is designated as Alpha Scorpii. It is the 15th brightest star visible from Earth. It's outer layers are so swollen it would extend out past the orbit of Mars if it was located where our Sun is at. It also has a companion star that is a blue-white main sequence star. It illuminates part of the Rho Ophiuchi cloud complex. As with many stars with this size, it most likely will explode as a supernova in the future.
Wolf359 is a red dwarf star at a distance of 7.8 light years away from Earth. Located in the constellation of Leo it is one of the nearest stars. It is also one of the faintest low mass stars known. So despite its closeness, it takes a telescope to see it as it shines at a dim magnitude 13.5. A relative young star at less than 1 billion years, as a red dwarf, it will survive for a trillions of years. It is also a flare star with a high rate of flares. It possibly has two planetary objects around it. The Wolf designation comes from Max Wolf who studied high proper motion stars and kept a catalog of them. It's motion can be seen over the years across the sky.
The nebula patterns and brightness slowly changes over months and years from shadows of dust clouds illuminated by the star R Monocerotis, which in itself encased in a dust cloud. Discovered by William Herschel, and studied by Edwin Hubble who it is named after.
An animated sequence of yearly images of the nebula, how much is due to different processing and different scopes and camera I don't know, but changes are visible in the nebula.