Story behind hare constellation under Orion


By Tom Burns - Stargazing



‘Tis the season when purveyors of public programs in astronomy talk much about Orion and his environs. His faithful huntin’ dawg Canis Major follows at his feet.

He raises his club in an unending battle with the pugnacious bull, Taurus. He stands with brave resolution on a helpless bunny rabbit.

In the latter case, we’re talking Lepus, the Hare, a somewhat sturdier version of our domestic rabbit. For one thing, they have enormous ears. All the better to hear you with, my dear. Their powerful hind legs endow them with the strength to hop like Hades. All the better to escape their many predators.

They seem pretty benign as they nibble gently on our garden produce. However, Orion has a good reason for standing on the bunny, as we shall see.

Nurturing Lepus stands in sharp contrast to the studly warrior and hunter Orion to its north. Look for it underneath Orion’s rectangular-shaped outline.

This old galley rhyme, which I found in RH Allen’s wonderful old book “Star Names: Their Lore and Meaning,” will tell you where to look:

“Orion’s image in the south

Has four stars — small but fair;

Their figure quadrilateral

Points out the timid Hare.”

As Orion stands on Lepus, he celebrates his victory over that fluffy denizen of the night. Yet to the ancients, the hare’s reproductive capabilities could be dangerous in their own inimitable way, as a story associated with Lepus suggests.

The reason for Orion’s odd rabbit-corpse vigil traces far back to a deadly (no kidding) outbreak of rabbits on the Greek island of Leros.

Hyginus, a Roman writer of the first century BCE, is the source of the tale. However, Hyginus oddly makes no mention of Orion.

Please forgive me for adding a few Orion-related flourishes of my own.

The island of Leros, off the southwest coast of Turkey, had no hares, or so the story goes. They were considered very tasty, so some industrious soul got the bright idea of bringing in a pregnant female. Well, we all know what those long-eared rascals like to do.

So pretty soon, the island, which is only 20 or so square miles in size, was crawling with Thumper’s cousins. They ate everything, including the entire agricultural output of the island. The populace was reduced to starvation.

The Lerosians had to work hard at stemming the bunny epidemic. You’ll know what I mean if you’ve tried to chase down a rabbit. In my version of the story, the inhabitants sought the help of the mighty hunter Orion.

Orion was not averse to rabbit slaughter. He once boasted that he had killed every kind of animal on Earth. What are a million or so delectable rodents, more or less?

Besides, Orion was not the brightest bulb that ever lit up the cosmos, if you know what I mean: “Me strong. Me brave. Me kill all the bunnies. Ha, ha, ha!”

With some Lerosian help, Orion slaughtered most of the hares and drove the rest into the sea. The Lerosians were finally rid of their cottontail pestilence.

The gods put Lepus in the sky to remind themselves (and us) to avoid wretched excess. Orion is standing on the hare to make sure it stays put.

Beyond that story, the ancient writers have very little to say about what they must have considered an obscure constellation. Hyginus claims that the Hare was placed among the stars by Mercury (Hermes to the Greeks), the swift-footed messenger of the gods, to honor its swiftness.

But speed is not the only characteristic that Mercury intended to honor. The god also wanted to celebrate the hare’s unique procreative talent. Hyginus writes that “hares have the exceptional power among quadrupeds of giving birth and being pregnant at the same time.”

I am not a biologist, so I cannot vouch for the hare’s incredible reproductive talent. During the first century CE, the Greek writer Pseudo-Eratosthenes traces a description of the hare’s ability to give “birth to some offspring, while it bears others in its womb” to none other than Aristotle himself.

As Aristotle wrote in his Historia Animalium (History of Animals), “Hares breed and bear at all seasons, superfetate (i.e., get pregnant again) during pregnancy and bear young every month.”

Astronomically speaking, Lepus is not the most interesting of the constellations. The Hare’s stars are faint compared to the intensity of Orion’s bright stars. The light pollution from Columbus, our neighboring city to the south, practically erases the constellation. Besides, Lepus isn’t exactly full of objects for the telescopist to observe.

One barely notable object is a globular cluster marked as M79 on most star maps. This dense ball of more than 100,000 stars is as bright as perhaps 90,000 of our suns, but it’s so far away that it isn’t much to look at.

M79 is visible in binoculars as a faint, fuzzy patch. A moderate-sized telescope will begin to resolve some stars around its edges. At 42,000 light-years away from Earth, M79 is about as far away as you can get and still be in our Milky Way galaxy. (One light-year equals 5.9 trillion of your puny Earthling miles.)

It took 170 years after the invention of the astronomical telescope for French astronomer Pierre Méchain to stumble upon it in 1780. Still, it’s worth a look if you can escape the city light pollution and have a telescope big enough to resolve it into a myriad explosion of stars.

The diehard telescopists among us have noted its odd shape and informally dubbed it the “Starfish Cluster.” Check it out if you get a chance. Lepus wouldn’t be worth bothering about except for one extraordinary star called R Leporis. Long ago, when I spent a lot of time loitering on the front lawn at Perkins with a telescope, I always found time to point my ‘scope at this strange star. You’ll need dark, rural skies to see it in all its glory.

Over about 428 days, “R” changes from very dim, so that it can be seen only in a large telescope, to nearly naked-eye brightness, and then back to dim again.

Because such variable stars have reached their decrepitude, they change enormously in their brightness.

As stars age, they have less hydrogen to burn into helium. As their thermonuclear fires falter, they cool off. The explosive pressures at their center cause them to expand to enormous size, radiate a lot of energy into space, and get temporarily brighter.

As the star radiates heat and light, the central explosive pressures lessen. Gravity takes over, allowing them to contract a bit and become dimmer. That cycle can repeat itself many times before the star finally burns out.

At less than 6,000 degrees Fahrenheit, R’s temperature is much lower than that of a yellow star like our sun, which is medium hot at 10,000 degrees.

Its low temperature allows R to keep a lot of carbon in its atmospheric shell. The carbon filters out the blue light as R’s light shines through its atmosphere. That filtration enhances its distinctive red color, which is already quite ruddy owing to the star’s relative coolness. And that’s what makes R so entertaining. In a sky filled with white stars, bluish stars, and even pale orange stars, R shines a deep crimson.

Its discoverer, J.R. Hind, described it in 1845 as “resembling a drop of blood on the background of the sky.” Color, especially red, is hard for the human eye to discern at night. Hind’s Crimson Star, as R Leporis is sometimes called, simply blows you back from the telescope.

Observing a star like R can be a frustrating experience because its brightness affects its color. One year, it is easy to find in binoculars, but it looks more coppery than red. The following year, only a telescope will show it, but then it appears as a glowing drop of deep red wine on the face of the night. However, its ruddiness never fails to amaze. Observed over time, it looks like a crimson heart beating oh-so-slowly to the rhythm of the cosmos.

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By Tom Burns

Stargazing

Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.