WPBT2's Star Gazers

Episode #13-07 "The Four Brightest Stars of Orion the Hunter"
Air Dates Febtuary 18, 2013 - February 24, 2013

JAMES: Hey there Star Gazers. I'm James Albury of the Kika Silva Pla Planetarium in Gainesville Florida.

MARLENE: And I'm Marlene Hidalgo, science teacher from Miami Dade County Florida

DEAN: And I'm Dean Regas, astronomer from the Cincinnati Observatory.

JAMES: Almost everyone knows that the most famous star pattern of winter is Orion the Hunter. And although everyone loves his red shoulder star Betelgeuse, Orion's other three bright stars are also quite wonderful. Let's show you.


MARLENE: O.K., we've got our skies set up for any clear night in February from 7 to 9 p.m. your local time. And if you look south you'll see Orion in all his glory. The dead giveaway is the three stars, equally spaced in a row, which mark his belt. Above the belt are the two bright stars, which mark his shoulders and below are the two bright stars which mark his knees.

DEAN:  The name Betelgeuse supposedly comes from an Arabic word which means "armpit of the central one" and is correctly pronounced bet-el-jooz. But most people pronounce it beetle juice so they can remember it.  Because if you stepped on a beetle, you'd get red beetle juice. At least that's what lecturers in planetariums have been telling kids for years.


JAMES: At any rate Betelgeuse is a gigantic red variable star. When it contracts to its smallest size, it is 500 times as wide as our million mile wide sun but when it expands to its largest size, it is almost 900 times as wide. And its red color indicates that it is a much cooler star than our yellow sun.

MARLENE: Orion's other shoulder star is named Bellatrix, which in Arabic means the conqueror. And although it is much smaller than Betelgeuse it still is seven solar diameters, which means it is seven times as wide as our sun. And it is a pale blue-white star, which means that it is many, many times hotter than both red Betelgeuse and our yellow sun.

DEAN: Orion's left ankle is a white supergiant star named Rigel. And it is much larger than Bellatrix, 92 solar diameters or 92 times as wide as our sun. His other knee-star, named Saiph is blue in color and is likewise a super giant, although somewhat smaller, 21 solar diameters. Which makes our sun look really puny next to it or any of Orion's four brightest stars.


JAMES: Now although experts disagree as to the exact distance of each of these stars from Earth, they are all hundreds of light years away, which means that when we look at them we see them not as they exist now but as they existed some time in the past depending on how far away they are.

MARLENE: For instance when we look at Bellatrix we see it as it existed 243 years ago because it is 243 light years away and it takes that long for its light to reach us.

DEAN: We see Betelgeuse as it existed 429 years ago because it is 429 light years away. But as far away as his shoulder stars are his knee stars are much, much farther.

JAMES: Indeed, Rigel is 777 light years away

MARLENE: And Saiph is 725 light years away. Wow!

DEAN: Now let's look at something a bit closer to home



DEAN: Look up to the right of Orion and you're sure to spot a bright white light in the night sky, Jupiter.

MARLENE: And next week you'll have a great chance to actually notice Jupiter move from night to night. Use a pair of binoculars and look just above Jupiter for a pair of stars. They're about 2 degrees, that's four moon widths, above Jupiter. Look on the night of Feb. 27th and Jupiter and this pair of stars will be in line. Keep watching over the next ten nights and you'll see Jupiter move out of line with these two stars. March 1st, March 3rd, March 5th, March 7th and March 9th. Neat, huh?

JAMES: And another reason to practice using your binoculars is that, tada! Comet Panstarrs may be visible in the western sky after sunset in about two weeks. Comets are notoriously unreliable but when they behave they can be an unforgettable sight.

DEAN: So there you have it the four brightest stars of Orion the hunter, each one much larger than our own sun.

MARLENE: And so far away that no one alive today will see what they actually look like in the present time. Something to think about and marvel at as you….

THREE: Keep looking up!


Episode #13-07 "The Four Brightest Stars of Orion the Hunter"
Air Dates Febtuary 18, 2013 - February 24, 2013

MARLENE: The four brightest stars of winter's Orion are absolutely incredible.


JAMES: First look south for three equally spaced stars in a row. Then up to the left is one of his shoulder stars Betelgeuse, which is a gigantic red variable star.

MARLENE: At its smallest it is 500 times as wide as our sun and at its largest 900 times as wide.

JAMES: His other shoulder star Bellatrix is pale blue and seven times as wide as our sun.

MARLENE: His western ankle Rigel is 92 times as wide.

JAMES; And his other knee Saiph is 21 times the width of the sun. So our million mile wide sun is really puny compared to Orion's shoulder and knee stars and thank heavens they're all hundreds of times farther away than our sun or we'd all be crispy critters.

MARLENE: And there's another bright light just up and to the right of Orion. It's the largest planet in our sun's family, Jupiter.

BOTH: Keep looking up!


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