Southern Crab Nebula

 Southern Crab Nebula

In celebration of the 29th anniversary of the launch of NASA's Hubble Space Telescope, astronomers captured this festive, colorful look at the tentacled Southern Crab Nebula.

The nebula, officially known as Hen 2-104, is located several thousand light-years from Earth in the southern hemisphere constellation of Centaurus. It appears to have two nested hourglass-shaped structures that were sculpted by a whirling pair of stars in a binary system. The duo consists of an aging red giant star and a burned-out star, a white dwarf. The red giant is shedding its outer layers. Some of this ejected material is attracted by the gravity of the companion white dwarf.

The result is that both stars are embedded in a flat disk of gas stretching between them. This belt of material constricts the outflow of gas so that it only speeds away above and below the disk. The result is an hourglass-shaped nebula.

The bubbles of gas and dust appear brightest at the edges, giving the illusion of crab leg structures. These "legs" are likely to be the places where the outflow slams into surrounding interstellar gas and dust, or possibly material which was earlier lost by the red giant star.

The outflow may only last a few thousand years, a tiny fraction of the lifetime of the system. This means that the outer structure may be just thousands of years old, but the inner hourglass must be a more recent outflow event. The red giant will ultimately collapse to become a white dwarf. After that, the surviving pair of white dwarfs will illuminate a shell of gas called a planetary nebula.

The object was first reported in the late 1960s, but was assumed to be an ordinary star. In 1989, astronomers used the European Southern Observatory's La Silla Observatory in Chile to photograph a roughly crab-shaped extended nebula, formed by symmetrical bubbles.

These early observations only showed the outer hourglass emanating from a bright central region. Hubble photographed the Southern Crab in 1999 to reveal complicated nested structures. These latest images were taken in March 2019 with a wide set of color filters on Hubble's newest, sharpest detector, Wide Field Camera 3. This image is a composite of observations taken in various colors of light that correspond to the glowing gases in the nebula. Red is sulfur, green is hydrogen, orange is nitrogen, and blue is oxygen.

Credits

NASA, ESA, and STScI

About The Object
Object Name Southern Crab Nebula; He2-104
Object Description Nebula with symbiotic Mira variable and white dwarf pair
R.A. Position 14:11:52.09
Dec. Position -51:26:24.39
Constellation Centaurus
Distance 10,700 light-years
Dimensions Image is 1.4 arcmin across (about 4.4 light-years).
About The Data
Data Description The HST observations include those from program
Instrument WFC3/UVIS
Exposure Dates 11-14 March 2019
Filters F475W, F502N, F606W, F656N, F658N, F673N
About The Image
Color Info These images are a composite of separate exposures acquired by the WFC3 instrument on the Hubble Space Telescope. Several filters were used to sample narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F502N Orange: F656N Green: F658N Red: F673N
Compass Image A nebula that consists of two multi-color horseshoe-shaped structures aligned so that they point in opposite directions, forming an hourglass shape. They are made of a patchwork mix of yellow, orange, red, and blue. Within the openings of the horseshoes on each side are streaks of yellow and orange that radiate outward from the center, giving them the appearance of crab legs. At the center of the hourglass shape is a star with a bright-white central core that is surrounded by a fuzzy blue halo and has four diffraction spikes radiating from its center. (This is actually two stars that are so close together they appear as one star.) A distinct figure-eight structure with multiple layers of orange, red, and blue sits behind the central star.
About The Object
Object Name A name or catalog number that astronomers use to identify an astronomical object.
Object Description The type of astronomical object.
R.A. Position Right ascension – analogous to longitude – is one component of an object's position.
Dec. Position Declination – analogous to latitude – is one component of an object's position.
Constellation One of 88 recognized regions of the celestial sphere in which the object appears.
Distance The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
Dimensions The physical size of the object or the apparent angle it subtends on the sky.
About The Data
Data Description
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
Instrument The science instrument used to produce the data.
Exposure Dates The date(s) that the telescope made its observations and the total exposure time.
Filters The camera filters that were used in the science observations.
About The Image
Image Credit The primary individuals and institutions responsible for the content.
Publication Date The date and time the release content became public.
Color Info A brief description of the methods used to convert telescope data into the color image being presented.
Orientation The rotation of the image on the sky with respect to the north pole of the celestial sphere.