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12/12/2013 – Ephemeris – The bright star Betelgeuse (Don’t say it three times)
Ephemeris for Thursday, December 12th. The sun will rise at 8:10. It’ll be up for 8 hours and 52 minutes, setting at 5:02. The moon, 3 days past first quarter, will set at 4:26 tomorrow morning.
The bright red star in the constellation Orion’s shoulder is Betelgeuse, and it’s about 643 light years away. Despite its great distance, it is the star whose surface is easiest seen, after the sun of course. That’s because it’s so big, maybe as large around as the orbit of Jupiter. Its true diameter is hidden by the cloud of gas it’s expelling. Betelgeuse varies in size and brightness, so its size varies by nearly 30 percent. The Hubble telescope has sent back pictures of the star, and has found a bright spot, seen in ultraviolet light on what may be its surface. It has a really hot core generating energy that pushes out its gaseous envelope to a great size. Some astronomers think the Betelgeuse will become a supernova within a million years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran, the Hyades, of Taurus, Orion and the Pleiades at 10 p.m. December 12, 2013. Created using Stellarium.
“This artist’s impression shows the supergiant star Betelgeuse as it was revealed thanks to different state-of-the-art techniques on ESO’s Very Large Telescope, which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate. The scale in units of the radius of Betelgeuse as well as a comparison with the Solar System is also provided.” Credit: ESO/L. Calçada (ESO is the European Southern Observatory)
12/10/2013 – Ephemeris – The bright star Aldebaran, the Follower
Ephemeris for Tuesday, December 10th. The sun will rise at 8:08. It’ll be up for 8 hours and 53 minutes, setting at 5:02. The moon, 1 day past first quarter, will set at 2:18 tomorrow morning.
The central constellation of winter, Orion, is in the east southeast at 9 p.m. Above it is Taurus the bull. The bright orange star in Taurus is Aldebaran. Aldebaran appears at the lower left tip of a letter V group of stars lying on its side that is the face of the bull. Aldebaran isn’t actually part of the group, called the Hyades star cluster. The cluster is about 153 light years away, while Aldebaran is 65. The star has an orange hue because its surface is cooler than the sun’s. However Aldebaran is 44 times larger in diameter, and shines 465 times brighter than the sun. The name Aldebaran means “Follower” because it follows the Pleiades star cluster through the skies. The Pleiades is above right of Aldebaran.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran, the Hyades, of Taurus, Orion and the Pleiades at 10 p.m. December 10, 2013. Created using Stellarium.
12/09/2013 – Ephemeris – The bright star Capella, the she-goat
Ephemeris for Monday, December 9th. The sun will rise at 8:07. It’ll be up for 8 hours and 54 minutes, setting at 5:02, the earliest sunset of the year. The moon, at first quarter today, will set at 1:12 tomorrow morning.
A bright star called Capella is now high in the east. Capella is the farthest north of winter’s seven brilliant first magnitude stars. Capella never quite sets for anyone north of Ludington. Due to its brightness, and being the closest first magnitude star to the pole, Capella appears to move slowly as the earth rotates, and spends summer and autumn evenings close to the horizon and is a reminder that winter’s not far away. It has in years past elicited a few phone calls and other queries about that ‘bright object in the northeast’. Capella belongs to the pentagonal constellation of Auriga the Charioteer. Capella represents a mother goat he is holding. Three stars in a thin triangle nearby to the star’s right are her kids.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Constellations Cassiopeia, Perseus and Auriga. Created using Cartes du Ciel
Note the small slender triangle of stars under the “p” in Capella. That’s the Kids, an asterism or informal constellation.
10/25/2013 – Ephemeris – Fomalhaut the lonely star actually has companions
Ephemeris for Friday, October 25th. The sun will rise at 8:11. It’ll be up for 10 hours and 30 minutes, setting at 6:41. The moon, 1 day before last quarter, will rise at 11:56 this evening.
The lonely bright star low in the south at 9 p.m. these evenings is Fomalhaut the harbinger of autumn in my book. Fomalhaut has a recently discovered planet orbiting it Fomalhaut lower case b. However astronomers just announced the discovery of a third star in the system. I didn’t know it had two. The second star, Fomalhaut (capital) B is a binocular object 2 degrees of 4 moon widths south or below Fomalhaut. The just reported third star (now Fomalhaut big C) is a red dwarf star nearly 6 degrees or 11 moon diameters to the north of Fomalhaut or should I say Fomalhaut A. This star is 3 light years from the primary star which is itself only 25 light years from us. I think the more we study this star the more alphabet soup we’ll find.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The bright star Fomalhaut all alone at 8:30 p.m. Created using Stellarium.
10/17/2013 – Ephemeris – The lonely star
Ephemeris for Thursday, October 17th. The sun will rise at 8:00. It’ll be up for 10 hours and 53 minutes, setting at 6:54. The moon, 1 day before full, will set at 7:37 tomorrow morning.
There’s a bright star that appears for only seven and a half hours on autumn evenings. It’s appearance, low in the southeast at 10 p.m., is a clear indication of the autumn season. The star’s name is Fomalhaut, which means fish’s mouth. That’s fitting because it’s in the constellation of Piscis Austrinus, the southern fish. At our latitude it’s kind of the fish that got away, because Fomalhaut appears to be quite alone low in the sky. The dimness of the constellation’s other stars and location close to the horizon make the faint stars hard to spot. The earth’s thick atmosphere near the horizon reduces their brightness by a factor of two or more, so Fomalhaut, one of the brightest stars in the sky, keeps a lonely vigil in the south.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The bright star Fomalhaut all alone at 9 p.m. Created using Stellarium.
07/25/2013 – Ephemeris – Vega, the fifth brightest night-time star
Ephemeris for Thursday, July 25th. The sun rises at 6:21. It’ll be up for 14 hours and 54 minutes, setting at 9:15. The moon, 3 days past full, will rise at 10:43 this evening.
The star Vega, which is nearly overhead or the zenith is a special star for astronomers. It’s part of the small constellation of Lyra the harp, which includes the parallelogram of stars near it. Vega is kind of a standard calibration star. It is the 5th brightest night-time star with a brightness of 0 magnitude, although recent measurements place it at 0.03. Of the spectral types which denote the star’s color and surface temperature, Vega comes out to be pure white, with a surface temperature nearly twice the sun’s. It’s almost exactly 25 light years away, and so is one of the closer stars. It’s a tenth the sun’s age and 40 times the sun’s brightness. It has perhaps a Jupiter sized planet, and a Kuiper belt of Pluto like objects orbiting it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Magnified view of Lyra showing Vega. Created using Stellarium.
07/22/2013 – Ephemeris – The star Deneb, brighter than it looks
Ephemeris for Monday, July 22nd. Today the sun will be up for 15 hours, setting at 9:18. The moon, at full today, will rise at 9:00 this evening. Tomorrow the sun will rise at 6:19.
At 11 this evening the bright star Deneb in Cygnus the swan will be moderately high in the east northeast. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is nearly overhead, and Altair to the south. While Deneb’s apparent magnitude, or brightness as seen from earth, makes it the dimmest of the three bright stars, Deneb’s vast distance of possibly 2,600 light years makes it 100 times the distance of Vega. If brought as close as Vega, Deneb would be several time brighter than Venus. For all this it is only 13-20 times the mass of the sun. It will have an extremely short life and it will explode, go supernova, in perhaps a few million years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Deneb with the other stars and constellations in the Summer Triangle. Created using Stellarium.
07/18/2013 – Ephemeris – The bright star Altair
Ephemeris for Thursday, July 18th. Today the sun will be up for 15 hours and 7 minutes, setting at 9:22. The moon, 3 days past first quarter, will set at 2:56 tomorrow morning. Tomorrow the sun will rise at 6:15.
Of the three stars of the Summer Triangle Altair in the constellation Aquila the eagle is the farthest one south and the closest. Altair is at a distance of 16.8 light years away. One light year is nearly 6 trillion miles. Altair is 10 times the brightness of the sun. While it’s almost twice the sun’s diameter, it rotates once in only 9 hours, and has a decidedly squashed appearance when seen close up. There are techniques that can actually accomplish this. Our sun’s a slow poke, taking nearly a month to rotate once. In science fiction the Altair system was the scene for the classic film Forbidden Planet, one of the few science fiction classic films of the 1950s.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
False-color image of the rapidly rotating star Altair, made with the MIRC imager on the CHARA array on Mt. Wilson.
United Planets Cruiser C57-D lands on Altair IV in the 1956 movie Forbidden Planet.
07/16/2013 – Ephemeris – The red giant star Antares
Ephemeris for Tuesday, July 16th. Today the sun will be up for 15 hours and 11 minutes, setting at 9:23. The moon, 1 day past first quarter, will set at 1:24 tomorrow morning. Tomorrow the sun will rise at 6:13.
Low in the south is the red giant star Antares. It lies at the heart of Scorpius the scorpion. Its name means Rival of Mars, because it has the same hue as the red planet. In Mars case the color comes from iron oxide, rust. In Antares case it has a cool surface temperature, relatively speaking of 5,700 degrees Fahrenheit. As a red giant star Antares is near the end of its life, though for a star Antares is young, possibly 12 million years old. That that age the sun was just getting started. But Antares with around 15 to 17 the sun’s mass has already run out of fusible hydrogen in its core and bloated out to over Mars orbit in size. Antares is 450 light years away and has a companion star in its system that looks greenish in contrast to Antares red. However when Antares A, the red giant’s light is blocked, the companion looks bluish.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellation Scorpius and the star Antares. Created using Stellarium.
07/15/2013 – Ephemeris – The moon will appear near Spica tonight
Ephemeris for Monday, July 15th. Today the sun will be up for 15 hours and 12 minutes, setting at 9:24. The moon, at first quarter today, will set at 12:48 tomorrow morning. Tomorrow the sun will rise at 6:12.
The moon this evening is very close to the bright star Spica. It might take a pair of binoculars to spot it in the glare of the moon. Spica will be just above left of the moon tonight. For other spots on the earth the moon will actually pass in front of the star. The event is called an occultation, from the word occult meaning hidden. Simply put the moon will pass in front of or hide the star for up to an hour. The chief beneficiary of this occultation is the state of Hawai’i. Occultations are one of the best ways to measure the position, diameter and shape of distant asteroids and Kuiper belt objects that are too small to measure otherwise. Satellites of these objects have also been discovered this way.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Spica and the Moon at 10 p.m. on July 15, 2013. Created using Stellarium.
Path on the Earth where the occultation of Spica will be visible. Credit Astronomical Almanac Online.
The Astronomical Almanac Online ( http://asa.usno.navy.mil/) “is a joint publication of the U. S. Nautical Almanac Office, United States Naval Observatory (USNO), in the United States and Her Majesty’s Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office (UKHO), in the United Kingdom.”
Bob Moler's Ephemeris Blog 