Constellations

Tucana the Toucan is home to the Small Magellanic Cloud

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November 17, 2023

Chart with four stars connected by lines and labels for Achernar to left, 47 Tucanae and Small Magellanic Cloud below. — The claim to fame for Tucana the Toucan is that it’s in the same direction in the sky as where we see the Small Magellanic Cloud, a dwarf galaxy orbiting our Milky Way. It’s also home to another beautiful deep-sky object, visible to the unaided eye; the globular star cluster 47 Tucanae.

Tucana the Toucan, deep in southern skies

The constellation Tucana the Toucan is visible year-round from Earth’s Southern Hemisphere. That’s because it’s near the south celestial pole, the point in the sky around which all southern stars revolve. So those of us in the Northern Hemisphere would have to travel southward on Earth’s globe to see Tucana. And, once we got there, we’d find that the stars of this constellation aren’t particularly bright or remarkable. Yet many of us know Tucana by name. Why?

It’s because this constellation is famous for being home to the Small Magellanic Cloud, the fuzzy patch in the sky that represents one of two relatively large dwarf galaxies orbiting our Milky Way. Plus, southern stargazers know that a large globular star cluster – 47 Tucanae, visible to the unaided eye – is also located within the boundaries of Tucana. In fact, this constellation’s stars are harder to pick out than the globular cluster and galaxy that anchor its southern edge.

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Stars of Tucana

The brightest star in Tucana is Alpha Tucanae, a magnitude 2.87 star that lies almost 200 light-years from Earth.

On the opposite side of the constellation from Alpha is Beta Tucanae, a star system containing six stars loosely bound together. Beta 1 is the brightest and shines at magnitude 4.36. Beta 2 shines at magnitude 4.53, and Beta 3 shines at 5.07. The whole Beta Tucanae system is an average of 140 light-years from Earth.

Chart showing Tucana the Toucan in white. There are many black dots for stars, and green lines for constellations. — You’ll find the Small Magellanic Cloud in the southeast corner of the constellation Tucana. The nearby bright star is Achernar, across the border in the constellation Eridanus the River. Chart by IAU. Used with permission.

Small Magellanic Cloud

Despite its great distance of 197,000 light-years, the Small Magellanic Cloud is one of the closest galaxies to Earth. You can see it without optical aid as a misty, cloudy patch from dark-sky locations. The Small Magellanic Cloud is an irregular galaxy but has a central bar as part of its structure, making it look like a disturbed former spiral. It’s the smaller of the two satellite galaxies in the Southern Hemisphere skies, with the larger being the aptly named the Large Magellanic Cloud.

The Small Magellanic Cloud has many clusters and nebulae within its expanse. An excellent target for a telescope, clusters stream through its length and out one tail. The Small Magellanic Cloud’s nearby kin, the Large Magellanic Cloud, lies in the constellations Mensa and Dorado. Both of these nearby galaxies are being sucked inward by our Milky Way Galaxy and will eventually be absorbed by it.

Hazy cluster of reddish and white stars, with tight cluster ball of stars to the right. — The Small Magellanic Cloud galaxy is a striking feature of the southern sky, but visible-light telescopes cannot get a clear view. Like the “cloud” in its name, the satellite galaxy also harbors obscuring dust clouds. The Visible and Infrared Survey Telescope for Astronomy (VISTA) allows a clearer view of the Small Magellanic Cloud. Notice also globular cluster 47 Tucanae to the right of the galaxy. Image via ESO/ VISTA VMC.

11 dish telescopes in front of starry background with 2 small, fuzzy, glowing patches in the sky. — View larger. | Can you spot Tucana the Toucan in this image of the night sky over the ALMA telescopes in Chile? The Small Magellanic Cloud lies within the border of Tucana. The bright ball of light to the upper right of the Small Magellanic Cloud is the globular cluster 47 Tucanae. Imagine the Toucan standing with its feet on the Small Magellanic Cloud. Image via ESO/ C. Malin.

47 Tucanae

The globular cluster 47 Tucanae also bears the catalog name NGC 104. It shines bright at magnitude 4.0 and is easily visible with the unaided eye. In excellent seeing conditions, it appears as large as the full moon. It’s the second brightest globular cluster of the Milky Way and contains millions of stars. Use binoculars or a telescope to resolve thousands of stars in the cluster.

47 Tucanae lies 14,500 light-years away. 47 Tucanae and the Small Magellanic Cloud may look close together, but that is only a line-of-sight coincidence. The Small Magellanic Cloud is about 14 times farther away.

Densely packed cluster of white stars with some orangish dots on the outskirts. — The Southern Hemisphere’s 47 Tucanae is the second brightest globular cluster in the sky as viewed from Earth. Millions of stars create this cluster. Image via NASA/ ESA/ the Hubble Heritage/ Wikimedia Commons.

Bonus globular cluster

Want a bonus observing target? On the opposite edge of the Small Magellanic Cloud’s curving shape from 47 Tucanae is NGC 362, another bright globular cluster. NGC 362 is a bit dimmer than 47 Tucanae, at magnitude 6.4, but still a good target in binoculars or small telescopes.

Small, hazy yellowish star cluster on the outskirts of a larger group of blue stars. — The globular cluster NGC 362 appears on the outskirts of the Small Magellanic Cloud. NGC 362 orbits the Milky Way in a highly eccentric orbit. Image via NASA/ JPL-Caltech/ University of Virginia/ R. Schiavon/ Wikimedia Commons.

The Hubble Deep Field South

The Hubble Space Telescope took a series of famous images called “deep fields” starting in the 1990s. In these images, the space telescope stared at what mostly looks like a blank area of sky for a long period of time, allowing the faint background objects to come to light. One of these images, the Hubble Deep Field South, came from a region of Tucana.

Star chart of Tucana in white. There are many black dots for stars and green lines for constellations around. — View larger. | The red circle shows the location of the Hubble Deep Field South in the southern constellation of Tucana the Toucan. All the stars on this chart are visible to the unaided eye on a dark, clear night. Image via ESO.

Black left corner and black background otherwise sprinkled with yellow and white ovals and dots. — View larger. | This image – Hubble Deep Field South – from the NASA/ESA Hubble Space Telescope is one of the first deepest visible/ultraviolet light images of the universe. The Hubble Space Telescope captured a tiny region of Tucana the Toucan in this image. Take some time to admire the huge array of galaxies in the deepest depths of space and from the early years of the universe. Image via R. Williams and the HDF-S team/ ESO.

Bottom line: Tucana the Toucan is a constellation in the Southern Hemisphere that’s a cinch to spot. Just look for our little satellite galaxy, the Small Magellanic Cloud. Two easy-to-observe globular clusters also reside here.

Posted

November 17, 2023

Constellations

Kelly Kizer Whitt

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About the Author:

Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. She began her career at Astronomy Magazine, and she has made regular contributions to AstronomyToday and the Sierra Club, among other outlets. Her children’s picture book, Solar System Forecast, was published in 2012. She has also written a young adult dystopian novel titled A Different Sky. When she is not reading or writing about astronomy and staring up at the stars, she enjoys traveling to the national parks, creating crossword puzzles, running, tennis, and paddleboarding. Kelly lives in Wisconsin.

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Tucana the Toucan is home to the Small Magellanic Cloud