The Carina Nebula in Three Colors
Astronomy Picture of the Day
Stars, like people, do not always go gentle into that good night. The above Carina Nebula, also known as the Keyhole Nebula and NGC 3372, results from dying star Eta Carinae's violently casting off dust and gas during its final centuries. Eta Carinae, one of the most luminous stars known, is visible as the bright star near the center of the nebula. The above picture was taken in three distinct colors of light: blue light as emitted from hot oxygen, green light as emitted by warm hydrogen, and red light as emitted by cool sulfur. Eta Carinae faded from being one of the brightest stars in the sky during the 1800s, but is still visible with binoculars in southern skies towards the constellation of Carina.
By University of Minnesota
Comet Hale-Bopp's Developing Tails Credit:
Astronomy Picture of the Day
Comet Hale-Bopp is living up to its expectations. Besides the brightness of its coma, a comet is typically remembered by the length of its tails. As visible in the above picture taken last week, Comet Hale-Bopp's blue ion tail shows a dramatic extension, with current reports of about 20 degrees from dark locations. The comet's white dust tail has so far shown a more modest extent but appears to be growing significantly. Comet Hale-Bopp's closest approach to the Sun occurs in about two weeks, and although it will not get much closer to the Sun than does our Earth, Comet Hale-Bopp is likely to tell even more spectacular tails then.
The Annotated Galactic Center
Astronomy Picture of the Day
The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders. Many are easily visible with binoculars. Constellations near the galactic center include Sagittarius, Libra, Scorpius, Scutum, and Ophiuchus. Nebulae include Messier Objects M8, M16, M17, M20 and the Pipe Nebula. Open star clusters include M6, M7, M18, M21, M23, M24, M25. Globular star clusters include M9, M22, M28, M54, M69, M70. And don't forget Baade's Window. Click on the photo to get the un-annotated version.
Our Increasingly Active Sun
Astronomy Picture of the Day
Our Sun is becoming a busy place. Only two years ago, the Sun was emerging from a solar minimum so quiet that months would go by without even a single sunspot. In contrast, already this year and well ahead of schedule, our Sun is unusually active, already nearing solar activity levels seen a decade ago during the last solar maximum. Our increasingly active Sun was captured two weeks ago sporting numerous interesting features. The image was recorded in a single color of light called Hydrogen Alpha, color-inverted, and false colored. Spicules carpet much of the Sun's face. The brightening towards the Sun's edges is caused by increased absorption of relatively cool solar gas and called limb darkening. Just outside the Sun's disk, several scintillating prominences protrude, while prominences on the Sun's face are known as filaments and show as light streaks. Magnetically tangled active regions are both dark and light and contain cool sunspots. As our Sun's magnetic field winds toward solar maximum over the next few years, whether the Sun's high activity will continue to increase is unknown.
By Mehmet Ergün
Palomar 13's Last Stand
Astronomy Picture of the Day
Globular star cluster Palomar 13 has roamed the halo of our Milky Way Galaxy for the last 12 billion years. The apparently sparse cluster of stars just left of center in this composite color digital image, it is one of the smallest, faintest globular clusters known. (The bright foreground star near bottom is unrelated and creates the spiky imaging artifacts.) Observations spanning forty years indicate that Palomar 13's galactic halo orbit is a highly eccentric one which, every one or two billion years, brings it relatively close to the galactic center. With each close approach to the Milky Way's central regions, gravitational tidal forces strip away the delicately bound cluster stars. In fact, detailed present day studies offer evidence for a dramatic end to this dwindling cluster's tidal tug of war. Palomar 13's latest close approach was only about 70 million years ago. But, when Palomar 13 again approaches the galaxy, it could well turn out to be the cluster's last stand.
The Carina Nebula in Three Colors
Astronomy Picture of the Day
Stars, like people, do not always go gentle into that good night. The above Carina Nebula, also known as the Keyhole Nebula and NGC 3372, results from dying star Eta Carinae's violently casting off dust and gas during its final centuries. Eta Carinae, one of the most luminous stars known, is visible as the bright star near the center of the nebula. The above picture was taken in three distinct colors of light: blue light as emitted from hot oxygen, green light as emitted by warm hydrogen, and red light as emitted by cool sulfur. Eta Carinae faded from being one of the brightest stars in the sky during the 1800s, but is still visible with binoculars in southern skies towards the constellation of Carina.
By University of Minnesota
Comet Hale-Bopp's Developing Tails Credit:
Astronomy Picture of the Day
Comet Hale-Bopp is living up to its expectations. Besides the brightness of its coma, a comet is typically remembered by the length of its tails. As visible in the above picture taken last week, Comet Hale-Bopp's blue ion tail shows a dramatic extension, with current reports of about 20 degrees from dark locations. The comet's white dust tail has so far shown a more modest extent but appears to be growing significantly. Comet Hale-Bopp's closest approach to the Sun occurs in about two weeks, and although it will not get much closer to the Sun than does our Earth, Comet Hale-Bopp is likely to tell even more spectacular tails then.