carbon stars

The Blue-Green Beauty of Planetary Nebulae

May 16, 2018 by Joe Bergeron Filed Under: Deep Sky

A long-exposure image of the Helix Nebula (NGC 7293) shows far more color than can be observed visually, even through a large telescope. Image credit: Terry Hancock.

New and would-be amateur astronomers are often mystified and disappointed by the lack of color in things they see through their telescopes. And why shouldn’t they be? Popular astronomy shows, magazines, and web sites encourage people to believe that celestial objects are rich with blistering, saturated color, much like the image above. Why doesn’t that new $400 8-inch Dobsonian show bright pink nebulae, and galaxies of blue and gold? [Read more…] about The Blue-Green Beauty of Planetary Nebulae

Share This:

Seeing Carbon Stars, Close Up and Far

September 22, 2017 by Brian Ventrudo Filed Under: Deep Sky

his ALMA image reveals much finer structure in the U Antliae shell than has previously been possible. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. During this period of only a few hundred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Examination of this shell in further detail also shows some evidence of thin, wispy clouds known as filamentary substructures. Credit: ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum

Many experienced stargazers are connoisseurs of carbon stars, deep-red and highly evolved stars that are dredging up carbon and other nuclear reactants from their innards on their way to becoming, briefly, planetary nebulae. These striking stars are the most colorful of all celestial sights and they’ve long intrigued astronomers who are trying to fine tune their theories of how stars come to the end of their lives. Carbon stars are too far away to reveal much detail directly, so astronomers study them indirectly by examining their spectra. But a team of researchers at the remarkable ALMA telescope in northern Chile have captured an amazingly beautiful and revealing image of a carbon star in the constellation Antlia. Let’s have a look at what they saw, then set some time aside to go see a carbon star for ourselves with a small telescope or pair of binoculars [Read more…] about Seeing Carbon Stars, Close Up and Far

Share This:

Star Tour – Cor Caroli and “La Superba”

April 14, 2017 by Brian Ventrudo Filed Under: Deep Sky

An artist's rendering of the carbon star La Superba in the constellation Canes Venatici. Credit: Wikipedia Commons. — An artist’s rendering of the carbon star La Superba in the constellation Canes Venatici. Credit: Wikipedia Commons.

Turn your gaze to the sky under the handle of the Big Dipper and you’ll see only two reasonably bright stars. These are the 3rd-magnitude stars Cor Caroli and 4th-magnitude Chara. Cor Caroli (the “Heart of Charles”) was named by Edmund Halley after the martyred English King Charles I. It is a pretty double star, easily split in a small telescope even at 30-40x. The blue-white primary shines at magnitude 2.9; the fainter yellow companion is magnitude 5.6 some 19 arc-seconds away from the primary. The pair is about 110 light years away [Read more…] about Star Tour – Cor Caroli and “La Superba”

Share This:

The Allure of Carbon Stars

January 27, 2017 by Brian Ventrudo Filed Under: Deep Sky

The carbon star R Leporis. Credit: Damian Peach

For visual observers with small optics, the colors of the deep sky range from subtle to nonexistent. Galaxies and nebulae cast too little light to stimulate the color-sensing cone cells in our retinas, so they appear pale gray-white or, in the case of a bright planetary nebulae, gray-green. Bright stars are a little more colorful. Betelgeuse appears clearly orange, even to the unaided eye, Rigel shines blue-white, and the showpiece double star Albireo in the constellation Cygnus shows off a blue-green primary and red-orange secondary in even the smallest telescope. Otherwise, star colors are quite subtle, especially to new stargazers. But there is one exception– carbon stars. These deep ruby-red stars, which dredge up nuclear soot from their innards, give off a striking glow that’s easy to see in a small telescope. See your first carbon star and you’ll want to see many more [Read more…] about The Allure of Carbon Stars

Share This: