Displaying items by tag: Variable Star
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.
Sometimes called the Oyster Nebula, NGC 1501 is a planetary nebula located in Camelopardalis (The Giraffe). The central star shed its outer layers and those layers are now illuminated by the central star. The central star is also reported to be a pulsating variable star with an extremely short period of brightness changes.
Also known as Herschel's Garnet Star is a supersized red giant star. It is among one of the larger stars known. If it was located where our Sun is, the outer layer would reach beyond the orbit of Jupiter. The lifetime of massive stars like this are measured in millions of years. Mu Cephei will most likely end as a supernova; with either a neutron star or a black hole remaining. As a (super) red giant, it varies in magnitude between 3.4 and 5.1. It is an estimated distance of 2,800 light years away. Located near the Elephant Trunk Nebula the area has many areas of dust and gas clouds nearby.
Imaged with the ED80cft refractor and the ZWO 1600 mono camera.
T Cancri is a red giant variable that gets it's deep reddish color from carbon that is dredged up from its core that forms a fine soot layer that scatters away the blue and green light, much like a sunset does. T Cancri varies in brightness from a magnitude 7.6 down to 10.5 in the green light band over a period of around 482 days. It was around magnitude 8.6 when this image was taken.
Other names for La Superba are Y CVn, and HD 110914. La Superba is a late stage red giant star, with a mass of three times that of our Sun, but with its outer layers extending out to a radius of 2.2 Astronomical units (1 AU is the distance of the Earth to the Sun). So if La Superba was at the same location as our Sun, it's outer layers would extend out to Mars. Like many red giants, it is also a variable star changing in brightness by around 1 magnitude over a 160 day cycle.
As Orion sets in the western sky, I say goodbye to one of the long period variable stars I follow until Fall when it starts rising in the east.
V Ori is a Mira type variable star that varies between 8.9 - 14.7 in V band over a period of approximately 267 days. Mira type variables are cool red giant stars that vary in brightness by over 2.5 magnitudes over periods that range from 80 to over 1000 days. The stars are in their late stage of life, fusing helium at the core and a swelling outer layer that is only weakly bound to the star. The star will eventually stop fusing, and transition to a white dwarf with a planetary nebula surrounding it. The pulsation is thought to be caused by shock waves originating from the star and traveling out through the extended shell.
Color image of V Ori taken on March 21, 2017, when it was around magnitude 9.6 in V visual band.
Light curve of V Ori, looking like it is near its peak on April 1st.
RX And is a recurring dwarf nova star located in the constellation of Andromeda. Currently classified in the class of Z Camelopardalis variable stars, it consists of a white dwarf with an accretion disk siphoning matter from a secondary dwarf star. Once the accretion disk reaches a certain threshold, it becomes very bright until it can slowly cool back down. Usually this cycle takes from 10-13 days for RX And, but occasionally it gets stuck in a bright mode for periods for days to even years.
As part of an AAVSO optical monitoring campaign in support of Chandra X-Ray observations, I've been taking photometric measurements once a night. The star normally varies from as dim as 14.8 to as bright as 10.3 magnitudes. With a quick rise time in under 24 hours, sunscreen would be an essential item for anyone near this star system. My exposure times went from 480 seconds at its dimmest to 50 seconds near its brightest. All images were taken through a "V" filter which is a standard green band pass filter used for observations with the 80 mm refractor.
Image taken the morning of September 7, 2016. It's magnitude was around 14.34 at the time, or about the same as the other stars near it. I needed an exposure time of at least 480 seconds to collect enough signal for an accurate reading.
By the morning of September you can see that now the star is much brighter than its nearest stars. It was then at a magnitude of 11.31 and using an image exposure of 50 seconds to keep from saturating the ccd pixels. The actual rise time took less than 24 hours to brighten to 11th magnitude.
An AAVSO chart of observations of RX And by different users, with my observations marked by crosshairs. It's easy to see the fast rise and fall times of the brightness changes.
It's been an interesting project for me.