Keywords: Sirius, white dwarf
1.06.2005
About 1,600 light-years away, in a binary star system fondly known as J0806, two dense white dwarf stars orbit each other once every 321 seconds. Interpreting x-ray data from the Chandra Observatory astronomers argue that the stars' already impressively short orbital period is steadily getting shorter as the stars spiral closer together.
Mira: The Wonderful Star
5.05.2005
To seventeenth century astronomers, Omicron Ceti or Mira was known as a wonderful star - a star whose brightness could change dramatically in the course of about 11 months. Modern astronomers now recognize an entire class of long period Mira-type variables as cool, pulsating, red giant stars, 700 or so times the diameter of the Sun.
Frosted Leaf Orion
16.11.2010
Sometimes, you can put some night sky in your art. Captured above Japan earlier this month, a picturesque night sky was photographed behind a picturesque frosted leaf. The reflecting ice crystals on the leaf coolly mimic the shining stars far in the background.
Winter Hexagon Over Stagecoach Colorado
2.01.2011
If you can find Orion, you might be able to find the Winter Hexagon. The Winter Hexagon involves some of the brightest stars visible, together forming a large and easily found pattern in the winter sky of Earth's northern hemisphere.
Spherical Planetary Nebula Abell 39
28.07.2005
Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules.
Sirius, Sun, Moon, and Southern Cross
7.07.2000
From left to right are the enclosures of Yepun (ye-poon; Sirius), Antu (an-too; Sun), Kueyen (qua-yen; Moon), and Melipal (me-li-pal; Southern Cross), pictured here as night falls at Paranal Observatory in northern Chile. These are the four 8.2 meter wide telescope units of the European Southern Observatory's Very Large Telescope (VLT).
The Planet, the White Dwarf, and the Neutron Star
18.07.2003
A planet, a white dwarf, and a neutron star orbit each other in the giant globular star cluster M4, some 5,600 light-years away. The most visible member of the trio is the white...
White Dwarf Stars Cool
1.11.1997
Diminutive by stellar standards, white dwarf stars are also intensely hot ... but they are cooling. No longer do their interior nuclear fires burn, so they will continue to cool until they fade away. This Hubble Space Telescope image covers a small region near the center of a globular cluster known as M4.
Hen 1357: New Born Nebula
3.04.1998
This Hubble Space Telescope picture shows Hen-1357, the youngest known planetary nebula. Graceful, gentle curves and symmetry suggest its popular name - The Stingray Nebula. Observations in the 1970s detected no nebular material, but this image from March 1996 clearly shows the Stingray's emerging bubbles and rings of shocked and ionized gas.
SN 1006 Supernova Remnant
4.07.2008
A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum.
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