Starship Asterisk*

Ann wrote:Adam Block has posted a new, fantastic image of R Aquarii.

http://en.wikipedia.org/wiki/R_Aquarii wrote:
R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary star system. The orbital period is approximately 44 years.[1] The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810. It has a distance of about 200 parsec, and is one of the nearest symbiotic stars and a well known jet source.[2]

By its gravitational pull, the white dwarf draws in material from the red giant and occasionally ejects some of the surplus in weird loops to form the nebula seen in the linked image.[3] The whole system appears reddened because it is situated in a very dusty region of space, and its blue light is absorbed before reaching us.

The nebula around R Aquarii is also known as Cederblad 211.
...
It is possible that the nebula is the remnant of a nova-like outburst, which may have been observed by Japanese astronomers, in the year 930 AD.

Ann

http://en.wikipedia.org/wiki/R_Aquarii wrote:
R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary star system. The orbital period is approximately 44 years.[1] The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810. It has a distance of about 200 parsec, and is one of the nearest symbiotic stars and a well known jet source.[2]

By its gravitational pull, the white dwarf draws in material from the red giant and occasionally ejects some of the surplus in weird loops to form the nebula seen in the linked image.[3] The whole system appears reddened because it is situated in a very dusty region of space, and its blue light is absorbed before reaching us.

The nebula around R Aquarii is also known as Cederblad 211.
...
It is possible that the nebula is the remnant of a nova-like outburst, which may have been observed by Japanese astronomers, in the year 930 AD.

[url=http://www.nasa.gov/mission_pages/NPP/news/earth-at-night.html][b][i]NASA-NOAA Satellite Reveals New Views of Earth at Night[/i][/b][/url]

---

This new global view of Earth's city lights is a composite assembled from data acquired by the Suomi National Polar-orbiting Partnership (NPP) satellite. The data was acquired over nine days in April 2012 and 13 days in October 2012. It took 312 orbits to get a clear shot of every parcel of Earth's land surface and islands. This new data was then mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.

The image was made possible by the satellite's "day-night band" of the Visible Infrared Imaging Radiometer Suite, which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires and reflected moonlight.

The day-night band observed Hurricane Sandy, illuminated by moonlight, making landfall over New Jersey on the evening of Oct. 29. Night images showed the widespread power outages that left millions in darkness in the wake of the storm.

Credit: NASA's Earth Observatory/NOAA/DOD