Looking Up column: Chasing Taurus the Bull

Peter Becker
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The Crab Nebula, M1, photographed by the Hubble Space Telescope.

It’s usually not a great idea to find yourself in front of a bull. That happened to me just once, on a trail. He made a nice display of aiming his horns and was scraping his front hoof on the ground as my friends and I scrambled up an embankment! Thankfully the farmer came by and led him away. Much safer but no less amazing in a different way is to chase after the bull in the night sky.

The constellation Taurus the Bull is immediately above Orion, due south around 9 p.m. in late January or early February. This region of the sky has many fascinating features that can be enjoyed without a telescope and is a real pleasure with binoculars.

Its most prominent star is fiery red Aldebaran, usually thought of as the eye of the bull. This is not to be confused with bright red-orange Betelgeuse, on the top left corner of the familiar Orion star pattern. Aldebaran is a short hop to the upper right of Orion. Aldebaran is a massive red supergiant star, 65 light-years distant. It’s so big, if it replaced the sun, its surface would nearly reach Mercury’s orbit - not good for Mercury - but I said “if.”

It’s easy to identify Aldebaran not just because of its magnitude and hue, but it is at the end of a remarkable, V-shaped open star cluster, the Hyades. This is the closest and largest star cluster visible. When seen in the southern sky, the “V” is on its side and marks the head of Taurus. Aldebaran is not part of this star cluster; by chance, it is positioned so it appears like part of the V pattern, but the star is much closer (and thus brighter to our eyes) than any of the Hyades’ stars (which are 151 light-years away).

All of the night’s stars rise in the east and set in the west, like the sun and moon, because the Earth on which we ride along, is spinning west to east. As it appears, the celestial bull is crossing the sky backward - tail first! This is quite unlike any earthly bull I know.

To the upper left of the Hyades is amazing star cluster the Pleiades, bright and compact. This is a favorite of mine to be sure, and no doubt of most “backyard astronomers.” The Pleiades can be thought of as the tip of one of the bull’s horns. This cluster is 444 light-years from here.

Over to the left (east) of Aldebaran and the Hyades are two easily visible stars, one further up than the other, right above Orion. Zeta Tauri is the one lower down, and Beta Tauri, higher up. Beta has been imagined as the tip of the bull’s other horn, and Zeta, his nose, making a long triangle with the Hyades’ “V.”

Other depictions, however, connect the stars differently and make Zeta Beta the tips of the two horns; the Pleiades then marks a shoulder. Fainter stars within Taurus to the right (west) of the Hyades are used to mark either the bull’s front legs or hindquarters.

The stars themselves, great balls of gas shining by nuclear fusion and at widely varying distances, know nothing of our imaginative names or patterns we use to help us remember and enjoy them all the more. A star-trekking astronaut traveling thousands of light-years would never recognize our familiar constellations and might wish to make his or her own.

Beta Tauri, commonly known as Elnath, is shared in depictions of the constellation Auriga the Chariot Driver, making Elnath one of the pattern’s stars. Auriga, discussed in the last column, is to the upper left of Taurus and highlighted by the brilliant yellow star Capella (nearly overhead on mid-evenings this time of year, as seen from the mid-north).

Taurus is along the ecliptic, the imaginary line on the sky which the sun follows, and the moon and major planets do so closely.

On very rare occasions, any constellation may temporarily be joined by what appears as a new star. It’s not a planet that happens to be crossing through, but an actual star that was invisible to the naked eye and suddenly erupted into brilliance. This might be a “nova,” which flares up and fades away, and may flare again. Then there is the exceedingly rare supernova when a star blows itself to smithereens.

This happened in Taurus the Bull, in the year 1054. The telescope had not yet been invented, but astronomers of the day didn’t need one to see this. The unexpected star was first noticed in July 1054 and remained visible for almost two years. At its peak, it was bright enough to be seen in daylight, estimated to have been magnitude -6. This is far brighter than Venus, which tops magnitude -4 as it orbits the sun.

Definite records of the supernova are known from Chinese, Japanese and Islamic star watchers. No certain records have been found from Europe, where the so-called Dark Ages were underway. A pictograph left by the Ancient Puebloan culture in New Mexico may depict the unusual star among its carvings.

Very close to Zeta Tauri (one degree away) is the remnant of the 1054 explosion. What is left is a cloud of dust ejected from the blast, visible as a hazy nebula. The slowly expanding cloud is already six light-years across. It is bright enough to catch with binoculars on a dark night. A small or medium-sized telescope shows its shape, which to me reminds me of a baby’s bootie. Nicknamed the Crab Nebula, its common catalog listing is M1. The Crab is 6,523 light-years away.

Last quarter moon is on Feb. 4. This week, catch planet Mercury very low in the southwest during twilight.

Keep looking up at the sky!

Peter Becker is managing editor at The News Eagle in Hawley, Pennsylvania. Notes are welcome at news@neagle.com. Please mention in what newspaper or website you read this column.

The constellation Taurus the Bull.