Hubble Heritage Archive

Hubble Heritage Archive - 1998

Hubble Heritage Archive: 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006

Gemini | Apollo | Hubble Space Telescope

Saturn October's first Hubble Heritage image is of Saturn. Saturn is an average of 9.5 A.U. from the sun, and it ranges from about 8.5-10.5 A.U. from Earth. The image was taken on September 30, 1996, for a total exposure time of 10 minutes.

To learn more about Saturn, view the Saturn page of this site.

October's second Hubble Heritage image is of SGR-I, a star field. 25,000 light-years from us, the Sagittarius Star Field lies in the constellation Sagittarius; this image covers approximately 1.8 arc minutes across (13.3 light-years). The image was originally taken on August 1, 1994, for a total exposure time of 2.8 hours.

While most of the innards of our galaxy are obscured from view by dense clouds of dust, there are a few narrow, dust-free regions. Through one of these, the Hubble Space Telescope peered through to offer this view of the Sagittarius Star Field. Some of these stars are among the oldest in the galaxy. By studying these, astronomers can learn more about the galaxy's evolution.

Many different colors of stars a re visible, which can be used to extrapolate the temperature, and then to estimate the age and mass.

NGC 7635 - The Bubble Nebula October's third Hubble Heritage image is of NGC 7635, AKA the Bubble Nebula, a nebula that is being shaped by a young star in its center. 11,300 light-years from us, the Bubble Nebula lies in the constellation Cassiopeia; this image covers approximately 2.6 arcminutes down, and the bubble is approximately 10 light-years across. The image was originally taken on September 6, 1992, for a total exposure time of 5 minutes.

There is a hot, massive star in the center of this expanding s hell of glowing gas. The shell is being shaped by a very strong stellar wind of material and radiation which is emanating from the bright star (visible near the left border) that is 10-20 times more massive than the sun.

Only part of the massive bubble - twice the distance between us and the nearest star (other than the sun) - is visible in this Hubble Heritage image.

The yellow gas in the lower right corner is a dense region of material that is being blasted by radiation from the Bubble Nebula's star, creating the finger-like tendrils and causing it to glow. The Bubble Nebula and the area around it is used to study how hot stars interact with surrounding interstellar material.

October's fourth Hubble Heritage image is of NGC 7742, a spiral galaxy. 72 million light-years from us, NGC 7742 lies in the constellation Pegasus; this image covers approximately 80 arcseconds across, and the entire visible object is about 36,000 light-years across. The image was originally taken on July 9, 1995, for a total exposure time of 1 hour.

This may look like a run-of-the-mill face-on spiral galaxy, but NGC 7742 is actually known as a Seyfert 2 active galaxy. This is a type that is probably powered by a large black hole residing in the center - the large yellow lump in the middle of this image.

The thick, lumpy ring around the core is an area of active star birth, about 3,000 light-years from the core. The spiral arms are tightly wound and faintly visible. Around the inner ring is a band of material which is probably the remnant of a once active stellar nursery.

NGC 3132 - Eight-Burst Nebula - Southern Ring Nebula - Planetary Nebula November's Hubble Heritage image is of NGC 3132, AKA the Eight-Burst Nebula, AKA the Southern Ring Nebula, a planetary nebula. 2,000 light-years from us, NGC 3132 lies in the constellation Vela; this image covers approximately 1.2 arcminutes down, and the nebula is about 0.4 light-years in diameter. The image was originally taken on December 7, 1995, for a total exposure time of 1 hour.

In this image, one can clearly see two central stars in the nebula - a large bright white one with a much smaller companion to the upper right of the main star. It is the smaller star that is responsible for the nebula. Its extremely hot temperatures cause it to radiate in ultraviolet light; this radiation is what makes the surrounding nebula fluoresce. The larger star is at an earlier stage of stellar evolution, but it will probably release its own planetary nebula once it dies.

Besides the two stars, this Hubble Heritage image shows many filaments made out of dust particles that have condensed from the gas. The nebula is color coded in temperature where blue is hottest and red is coolest.

December's Hubble Heritage image is of NGC 253, AKA The Sculptor Galaxy, AKA The Silver Coin Galaxy, a galaxy. 7.5 million light-years from us, NGC 253 lies in the constellation Sculptor; this image covers approximately 2.7 arcminutes down (5,800 light-years). The image was originally taken on May 29, 1994, for a total exposure time of 1.5 hours.

NGC 253 is an almost edge-on spiral galaxy, and it is one of the nearest galaxies beyond our Local Group (a small cluster of about 30 galaxies that contains the Milky Way and Andromeda galaxies).

This Hubble Heritage image presents the complex structures such as gas clouds, dark dust swaths, and young, bright star clusters - typical of spiral galaxies.

Caroline Herschel discovered NGC 253 in 1783 while searching for comets. The closeness to Earth presents an ideal target for amateur astronomers in the Southern Hemisphere.