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The mass of Venus is 4.868×1024 kg. That is about 82% of the mass of Earth. Alright, end of story and thank you for reading. Okay, we would never do that to you here at Universe Today. There are far too many interesting facts about Venus to leave you hanging like that.
Here are a few other physical characteristics of the second rock from the Sun:
Diameter
12,100 km
Surface Gravity
8.87m/s2
Surface Area
460,000,000 km2
Volume
9.38×1011km3
Surface Atmospheric Pressure
92 times that of Earth
Average Surface Temperature
462 degrees Celsius
Rotation
Retrograde
Density
5.204 g/cm3
Scientists believe that the high mass and density of Venus can be accounted for by its high concentration of rock and metals. They believe that the planet has a liquid metallic core that is surrounded by a molten rock mantle. Actual proof of this is nearly impossible since the reflective nature of the planet’s atmosphere makes many types of observation impossible.
Venus was once thought to be a dead planet. There is no life on the surface for many reasons, but recent study of the surface has revealed that there may be active volcanoes on the planet. That means that it is alive, geologically speaking. Previously, scientists had known that the planet had been resurfaced by volcanic activity 300 to 500 million years ago, but had thought that the activity died out during that same time frame.
There have been many missions sent to Venus. The Soviet space program started the race to Venus with the Venera program. It is hard to tell exactly how many Soviet missions to Venus were launched since the program would not announce a probe that failed, but more than a dozen were successful. NASA launched several mission of its own. Early missions from both programs failed because neither was prepared for the extreme pressure within the Venusian atmosphere. Even those that were able to transmit from the surface could only survive for less than one hour.
The Venus Express is currently in orbit around Venus. BepiColumbo is set to launch in 2014. It is hoped that the Akatsuki probe can reawakened to gather information when it arrives in the area in 2016 and the Venus In-Situ Explorer is in the planning stages. Scientists are determined to unravel the planet’s mysteries. Like you, they want to know more than the mass of Venus.
Image constructed from Venus Express data - atmospheric particles being stripped away by the Solar Wind (credit: ESA)
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Although it’s similar in size, Venus is very different from Earth. The temperature at the surface is hot enough to melt lead, with an atmosphere of almost pure carbon dioxide, 92 times thicker than Earth’s atmosphere. Even with this extreme environment, is it possible that there’s life on Venus?
Probably not.
Here on Earth, we find life wherever we find liquid water: kilometers deep underground, beneath glaciers, and even inside nuclear reactors. If there’s liquid water, there’s life. But there doesn’t seem to be any liquid water on Venus.
Scientists think that Venus did have liquid water billions of years ago, but a runaway greenhouse effect heated up the planet to the point that all the water evaporated, and was eventually lost to space. The atmosphere is now 96% carbon dioxide, with the rest nitrogen and a few other trace compounds.
But there’s another possibility. High up in the atmosphere of Venus, at an altitude of 50 km, the air pressure and temperature get to the point that they’re very similar to Earth. In fact, at this altitude, it’s the most Earthlike place in the whole Solar System. Some scientists think that there could be microbial life high up in the atmosphere of Venus.
Since the Sun’s solar wind is constantly blowing on Venus, and Earth is “downwind” from Venus, it’s possible that microbial life is being blown from Venus to Earth. Maybe life on Earth got its start on Venus.
You can read a longer article about the possibility of life on Venus here. And here’s a video that shows how the atmospheres of Venus and Mars leak into space.
The first color pictures taken of the surface of Venus by the Venera-13 space probe. The Venera 13 probe lasted only 127 minutes before succumbing to Venus's extreme surface environment. Part of building a longer-lasting Venus lander is figuring out how to power it. Credit: NASA
You might be surprised to know that Venus is the hottest planet in the Solar System. The temperature across the entire planet is 735 Kelvin, or 462 degrees Celsius.
That makes it hotter than Mercury, which can dip down to -220 degrees Celsius and get up to 420 degrees C. Venus is nearly twice as far away from the Sun as Mercury, and receives 25% of it’s sunlight.
The temperature on the surface of Venus is the same across the entire planet. It doesn’t matter if it’s day or night, at the poles or at the equator – the temperature is always the same 462 degrees.
[/caption]So why is Venus so hot? Billions of years ago, the atmosphere of Venus was probably very similar to the Earth’s, with liquid water lasting on the surface. But a runaway greenhouse effect evaporated all the water, leaving a thick atmosphere of carbon dioxide. The light from the Sun is trapped by the carbon dioxide atmosphere and keeps the planet so warm.
It’s also believed that Venus once had plate tectonics like we have on Earth. Here on Earth, the plate tectonics help regulate the amount of carbon dioxide in the atmosphere by trapping excess carbon dioxide underneath the surface of the Earth. When the plate tectonics stopped, the carbon cycle stopped as well, and carbon dioxide was able to accumulate in the atmosphere of Venus.
Apollo 8's famous Earthrise picture. Would you like to have this view? Credit: NASA
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The Apollo 8 mission was a seminal moment not in only the history of spaceflight, but in human history as well. The mission came during a time when the US and the world were divided by war and racial issues. It’s been said that Apollo 8 “saved” 1968 from being an otherwise divisive and disheartening year, and because of the success of the mission – in terms of both technical and philosophical matters — the Apollo 8 crew of Frank Borman, Jim Lovell and Bill Anders were named “Men of the Year” by Time Magazine. Apollo 8 was the first human mission to orbit the moon, but it wasn’t supposed to be. And the mission was responsible for one of the most iconic images of our time.
Read more about Apollo 8 and watch an excellent video NASA put together to commemorate the mission on its 40th anniversary
Originally the mission was slated to test the lunar lander hardware in Earth orbit. But the lunar lander wasn’t ready and then other political issues came into play. NASA was told, incorrectly it turned out, by the CIA that the Soviet Union was preparing its own manned lunar mission and was ready to launch. As NASA wanted to be first to the moon and also fulfill President John Kennedy’s call for a US manned lunar landing by the end of the decade, they took a gamble and designated Apollo 8 to go and orbit the moon.
The decision was controversial. NASA’s giant Saturn V rocket, the only rocket capable of taking humans to the Moon, had been fraught with problems and instrument failures on its two test flights. Also, fresh in everyone’s minds was the fire in 1967 in which killed three astronauts – Gus Grissom, Ed White and Roger Chaffee – during a ground test of an Apollo capsule. Apollo 8 launch. Credit: NASA
Yes, it was a gamble, but it paid off. The crew launched on December 21, and it was the first manned launch of the Saturn V rocket. It went well, although Anders tells the story how he felt severe vibrations during the first moments of launch, and feeling almost like a bug on top of a car antenna, vibrating back and forth. But the giant rocket, 363 feet tall and weighing 6.25 million pounds performed well and following a rocket burn for trans-lunar injection, the astronauts were on their way to the moon.
Early on Christmas Eve, Apollo 8 reached its destination. The astronauts fired the propulsion system to slow the rocket, putting them into lunar orbit. For its first three obits, the astronauts kept its windows pointing down towards the Moon and frantically filmed the craters and mountains below. One of their main tasks was to do reconnaissance for the future Apollo landings.
It was not until Apollo 8 was on its fourth orbit that Borman decided to roll the craft away from the Moon and to point its windows towards the horizon in order to get a navigational fix. A few minutes later, he spotted a blue-and-white object coming over the horizon. Transcripts of the Apollo 8 mission reveal the astronauts’ wonder and amazement at what they were seeing: Earth, from a quarter of million miles away, rising from behind the Moon. “Oh my God! Look at the picture over there. Here’s the Earth coming up,” Borman shouted. This was followed by a flurry of exclamations by Anders and Lovell and a scramble to find a camera. Anders found one first and the first image he took was black-and-white, showing Earth just peeping over the horizon. Then Anders found a roll of 70mm color film for the Hasselblad camera, and he took the photograph of Earthrise that became an icon of 20th-century, portraying technological advances and heightening ecological awareness. Apollo 8 crew. Credit: NASA
This was the way humans first recorded their home planet from another world. “It was the most beautiful, heart-catching sight of my life,” Borman said later, “one that sent a torrent of nostalgia, of sheer homesickness, surging through me. It was the only thing in space that had any color to it. Everything else was either black or white. But not the Earth.”
Jim Lovell said that Earth was “a grand oasis in the vast loneliness of space.”
The three astronauts agree the most important thing they brought back from the mission was the photography, not only of the moon, but of Earth.
To commemorate the 40th anniversary of Apollo 8, the crew of the International Space Station’s Expedition 18, Commander Mike Fincke and Flight Engineers Sandy Magnus and Yury Lonchakov will send a message to be aired on a message that will air on NASA Television as part of the daily Video File, beginning at 11 a.m. CST, Friday, Dec. 19. The video also will be broadcast in high definition on the NASA TV HD channel at 10
a.m., noon and 3 p.m. on Friday, Dec. 19, and Tuesday, Dec. 23.
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When you look at the Moon and Mercury, their surfaces are pounded with impact craters. Mars has many craters, and even Earth has its share. But what about Venus, are there craters on Venus?
There are craters on Venus, but not many. The Solar System is relatively empty now, but less than a billion years after the formation of the Solar System, there were still many objects left over. These crashed into planets and moon, during a time scientists call the late period of heavy bombardment. Many of the craters on Mercury and the Moon were formed during that time.
Strangely, Venus shows no record of the heavy bombardment period. Either it didn’t get struck, which is unlikely, or some process resurfaced the planet, removing all traces of the impact craters. The resurfacing process stopped at some time in Venus’ more recent history. And so, all the craters that scientists do see on the surface of Venus are relatively young.
Craters on Venus are different from craters on other planets. The planet’s thick atmosphere stops the smaller objects from even reaching the surface of Venus; they just burn up in the atmosphere. There are about 1000 craters identified on the surface of Venus.
Crater Mead is the largest known crater on Venus, named after the American anthropologist, Margaret Mead. It measures 280 km in diameter, and contains several concentric rings.
We have written many articles about Venus on Universe Today. Here’s an article about the evolution of Venus’ surface, and here’s a “Where in the Universe” challenge featuring a crater on Venus.
Carbonates appear in green in this area about 20 km (12 miles) wide on Mars. NASA/JPL/JHUAPL/MSSS/Brown University
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Scientists from the Mars Reconnaissance Orbiter have made a major discovery about the history of water on Mars. The CRISM instrument, the Compact Reconnaissance Imaging Spectrometer for Mars, on board NASA’s Mars Reconnaissance Orbiter has found carbonates, a long-sought-after mineral, embedded in bedrock on the Martian surface. The Phoenix Mars Lander also discovered carbonates in soil samples, which was a surprise and MRO has observed carbonates in windblown dust from orbit. However, the dust and soil could be mixtures from many areas, so the carbonates’ origins have been unclear. The latest observations indicate carbonates may have formed over extended periods on early Mars. Additionally the new findings indicate that Mars had neutral to alkaline water when the minerals formed at these locations more than 3.6 billion years ago, and not the acidic soil that appears to dominate the planet today. This means that different types of watery environments have existed on Mars. The greater the variety of wet environments, the greater the chances one or more of them may have supported life.
“We’re excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars’ history,” said Scott Murchie, principal investigator for the instrument at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Carbonate rocks are created when water and carbon dioxide interact with calcium, iron or magnesium in volcanic rocks. Carbon dioxide from the atmosphere becomes trapped within the rocks. If all of the carbon dioxide locked in Earth’s carbonates were released, our atmosphere would be thicker than that of Venus. Some researchers believe that a thick, carbon dioxide-rich atmosphere kept ancient Mars warm and kept water liquid on its surface long enough to have carved the valley systems observed today.
“The carbonates that CRISM has observed are regional rather than global in nature, and therefore, are too limited to account for enough carbon dioxide to form a thick atmosphere,” said Bethany Ehlmann, lead author of the article and a spectrometer team member from Brown University, Providence, R.I.
On Earth, carbonates include limestone and chalk, which dissolve quickly in acid.
“Although we have not found the types of carbonate deposits which might have trapped an ancient atmosphere,” Ehlmann said, “we have found evidence that not all of Mars experienced an intense, acidic weathering environment 3.5 billion years ago, as has been proposed. We’ve found at least one region that was potentially more hospitable to life.” Possible carbonates in Nilli Fossae. Credit: NASA/JPL/University of Arizona
The researchers report clearly defined carbonate exposures in bedrock layers surrounding the 1,489-kilometer-diameter (925-mile) Isidis impact basin, which formed more than 3.6 billion years ago. The best-exposed rocks occur along a trough system called Nili Fossae, which is 666 kilometers (414 miles) long, at the edge of the basin. The region has rocks enriched in olivine, a mineral that can react with water to form carbonate.
“This discovery of carbonates in an intact rock layer, in contact with clays, is an example of how joint observations by CRISM and the telescopic cameras on the Mars Reconnaissance Orbiter are revealing details of distinct environments on Mars,” said Sue Smrekar, deputy project scientist for the orbiter at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The findings will appear in the Dec. 19 issue of Science magazine and were announced Thursday at a briefing at the American Geophysical Union’s Fall Meeting in San Francisco.
Rover Driver Scott Maxwell with a model of MER. Photo courtesy Scott Maxwell
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In January of 2004, NASA’s twin robot geologists, the Mars Exploration Rovers Spirit and Opportunity, landed on the Red Planet. During those nearly five years, the rovers have returned hundreds of thousands of images and enough data to keep scientists busy for decades. But almost nine years ago, Scott Maxwell started working on developing software and techniques for driving the rovers around on Mars surface. Today he’s the Mars Rover Driver Team Lead for MER at JPL, and he says that every day of working on this mission has been incredible. “It’s been an amazing experience,” he said, “and I like to say it’s the best job on two planets.” To celebrate the upcoming fifth anniversary of the rovers on Mars, Universe Today caught up with Scott to get an update on the current status of the two rovers, to find out what the five-year MER mission has been like for a rover driver, and to ask the pressing question, just how do you drive a rover from 150 million kilometers away?
Both rovers have been inactive recently because of solar conjunction, where the sun is between Earth and Mars, which makes communications difficult because the amount of radio noise generated by the Sun. So, when I talked to Scott on Wednesday of this week he was just working on the commands that would be sent to Spirit for the first drive she has taken since several weeks ago. So how is Spirit doing these days?
“Spirit is struggling valiantly to climb up the north face of Home Plate,” Scott said. “As you know, we’ve just come out of solar conjunction, and so we’re picking up where we left off on Spirit’s climb up the face. Her solar array energy levels are not as good as they were before the mini-dust storm we had before the conjunction, so that’s obviously a cause for concern. It’s unfortunate because that means we have less energy for driving. But she’s still alive and that’s a lot better than what we thought she’d be five years into the mission.” Home Plate is the raised plateau. Spirit is the dark spot at the 1 o'clock position. Image: NASA/JPL/University of Arizona
Home Plate is a low plateau about 80 meters (260 feet) in diameter. Spirit spent the Martian winter parked on the north side of the plateau with her solar panels slanted towards the low sun in order to stay alive. But Spirit’s solar arrays are severely dust-covered, decreasing the amount of power available for science activities and driving. But the scientists and engineers haven’t given up on Spirit, and still have big plans for her.
“Our longer term goal is to head south from Home Plate to a pair of features called ‘Goddard’ and ‘Von Braun’,” said Scott. “Von Braun is a hill and Goddard is a crater-like feature next to it, and that’s the next area we’d like to explore. As you know, the area around home plate appears to be a region of past hot-springs or volcanic fumarole activity, the kind of place where life might have formed on Earth, so it makes it a particularly exciting place to explore on Mars, as we try to find out more about what was going on here.”
But ‘Goddard’ and ‘Von Braun’ are on the south side of Home Plate and Spirit is on the north side. The easiest route would be to “climb back up on the top of Home Plate and kind of skate across it where the driving is good” Scott said, but if Spirit isn’t able to make the climb, they will drive down the north slope and go around Home Plate the long way. But that might take more time, and time might be getting limited for Spirit. Bonestell panorama, taken by Spirit during her winter stay on the north side of Home Plate. Credit: NASA/JPL/Cornell
So, the shortest way is up and over Home Plate. But Spirit has a bum right front wheel, and is trying to climb up some difficult terrain. “Imagine you’re in the desert, climbing up a sand dune, but every step you take the sand crumbles out from beneath you,” said Scott. “That’s what Spirit is experiencing. So even though we’re commanding the wheels to go several meters, she might only make a few centimeters of progress in a sol (Martian Day).”
But the driving team will keep trying, as ‘Von Braun’ and ‘Goddard’ are of interest to the science team.
Opportunity, on the other hand, is in very different driving conditions. “Right now she’s basically on a parking lot, with only a couple of speed bumps every once in awhile,” Scott said. “Opportunity can drive 100 meters a sol, like the length of a football field every day, without breaking a sweat. We recently had a nearly record-setting drive, with Opportunity where we drove nearly 216 meters in one day,” Scott said proudly. “So that’s our silver medal drive, our second longest drive ever with either of the rovers.” (The longest drive was 220 meters in one day.)
One thing Opportunity does have to watch out for is sand dunes in the region. In 2005, Opportunity became stuck in one of those dunes, and it took the rover driving team over a month to figure out how to maneuver Opportunity out of the sand trap, called Purgatory Dune. In honor of the difficulties and lessons learned from getting stuck, all the potential sand traps in the region are called “Purgatoids.”
“Opportunity is in a region where Purgatiods are all around her.” Scott said. “But the good news is that we have better data now, than we did when we first encountered these features.” The MER team now has the benefit of the Mars Reconnaissance Orbiter’s HiRISE Camera in orbit around Mars, looking down at — if not watching over – the rovers and their activities. “So we have the data and images from HiRISE, and we think we have identified a way to pick out these Purgatoids from orbit.” Scott said. “So we take the images from MRO, and use them as part of our path planning for Opportunity every day, and also for our longer scale path planning. On top of that we have other measures we have adopted after that first Purgatory incident, where the rover stops every once in awhile and ‘checks’ itself, gauging whether it is actually moving or if it is stuck and the wheels are just spinning. So even if we get into a Purgatoid, we’ll be able to catch it before too long and have the chance to get ourselves out before we dig in too far.”
But so far, with the new technique of being able to identify Purgatoids from orbit, Opportunity hasn’t run into a single one. Opportunity's traverse map through Sol 1716 As of sol 1707 (Nov. 11, 2008), Opportunity's total odometry was 13,493.85 meters (8.38 miles).
“It makes us happy to put the pedal to the metal and just drive,” Scott said, “It’s a lot of fun.”
Opportunity is “putting the hammer down” to reach a crater about 12 kilometers (7 miles) away called Endeavour. The huge crater is 22 kilometers (13.7 miles) across, and scientists expect to see a much deeper stack of rock layers than Opportunity saw while she was in Victoria Crater the past two years. The 12 km driving distance would match the total distance it has traveled from 2004 to mid-2008. Even at the 100-meter plus pace each sol, the journey could take two years.
But Scott Maxwell and the 13 other rover drivers working on the MER mission are up for the challenge.
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Like all the planets, Venus formed approximately 4.6 billion years ago when the Sun and the Solar System came out of the solar nebula. So, the age of Venus is 4.6 billion years old.
Before the Solar System, there was just a large cloud of hydrogen gas in a giant nebula. Some event, like a nearby supernova explosion put a shock into the cloud, and caused it to begin collapsing. Many stars, large and small, formed in this nebula, and one of these went on to be the Sun. As the material condensed together, conservation of momentum caused it to spin up and flatten out.
A protoplanetary disk of material formed around the newborn Sun, and it was here that the planets formed. Dust clumped together to form rocks, rocks smashed together into boulders, and mountain-sized objects became protoplanets. In the first few hundred million years of the age of Venus, it’s likely that the planet was smashed many times by these large asteroid and protoplanets. But eventually, Venus became the dominant object in the region, sucking in everything with its gravity.
We know that Venus was probably the victim of a large collision because it rotates in the opposite direction from the rest of the planets in the Solar System. A large collision could have turned its rotation backwards.
How do we know Venus’ age? We can’t measure the age of Venus directly, because of the intense heat and pressure on the surface of Venus. Instead, scientists measure the age of meteorites that have fallen to Earth. After analyzing hundreds of objects, scientists have found that they all formed at approximately the same time. These meteorites are the leftover pieces from the formation of the Solar System, and help prove that all the objects in the Solar System formed at the same time.
And so we know that the age of Venus is 4.6 billion years old.
We have written many articles about Venus. Here’s one about how life on Venus could be blown to Earth, and here’s an article about how you might keep a Venus rover cool.
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Space is totally inhospitable. If the freezing temperatures don’t get you, the intense radiation will kill you. Or the vacuum, or the lack of breathable atmosphere, or meteoroid impacts. Well… you get the idea. That’s why most space exploration is done by hardy robots. They don’t need to eat, drink or breathe. They get their energy from the Sun, and they’ve proven they’ve got the right stuff to explore every planet and major moon in the Solar System. Let’s hear it for the space robots.
If you love a cosmic mystery – and which one of us doesn’t – then you’re going to really enjoy what’s about to occur in the night sky. It all has to do with an easily located variable star in the constellation of Cepheus and an unseen companion which crosses its path every 5.6 years…
Click to enlarge mapThe star’s name is EE Cephei (RA 22 09 22.76 Dec +55 45 24.2) and and 10.8 magnitude it’s well within range of large binoculars and small telescopes. You’ll find it located about a degree and a half southwest of 4.2-magnitude Epsilon Cephei (about a finger width held at arm’s length). This will get you in the correct approximate field. For smaller optics you’ll see far fewer stars than what are depicted on the photographic chart, but the brighter ones will lead the way. However, in larger telescopes you’ll easy pick out the star patterns – so use the inset to help guide you to the right star! Now, here’s why it’s so important…
According to Mike Simonsen’s excellent blog: “This story starts in the 1950’s with the discovery of the variable nature of the star EE Cephei (Cep). Astronomers noticed it fainter than normal in 1947 and again in 1952. At first it was suspected of being an R Coronae Borealis type star. These are giant Carbon-rich, Hydrogen-poor stars that exhibit unpredictable fading episodes, believed to be caused by dust forming episodes in the outer layers of these stars’ atmospheres. The dust blocks the visible light, so we see the star fade, sometimes dramatically, by up to 9 magnitudes. It can take a year or more for them to return to maximum light, where they will shine contentedly for another undetermined period before coughing up dust and fading again.
When EE Cep faded again in 1958, Italian astronomers Romano and Perissinnotto suggested it might actually be an eclipsing binary with a very long period. Eclipsing binaries are stars that orbit around a common center of mass, and due to a line of sight effect we see them fade at regular intervals as one star passes in front of the other from our point of view. Sometimes, the alignment is so nearly edge on that we see a secondary eclipse as the smaller star of the binary pair disappears behind the primary. Because the orbits of these binaries are usually quite stable and the eclipses occur at regular intervals, observing eclipsing binaries is extremely helpful to astronomers in determining stellar masses, sizes, temperatures, luminosities and orbital parameters. Most have periods measured in hours, days or weeks because they are compact systems, with the stars in close proximity to each other, if not actually in contact.”
Exciting? Maybe not to some, but to those of us who not only enjoy astronomy as a passtime, but as a vocation – any event is welcomed and thoroughly studied. The EE Cephei event was confirmed after eclipses were observed again in 1964 and 1969 by L. Meinunger published the first ephemeris and established a period of 2049 days. All of this was well and good – but no secondary eclipse has ever been observed.
Says Mike: “The mysteries about this star were far from being unraveled though. One of the striking characteristics of EE Cep is the different eclipse depths and durations. Unlike many eclipses, whose periods can be measured to 8 significant digits, and whose range in magnitudes is very predictable, all of the observed eclipses of EE Cep have been different from each other in depth and duration.”
What’s happening is something strange is occurring with the light curve – it’s bottoming out and there may be a very good reason. As a highly respected member of the American Association of Variable Star Observers (AAVSO), Mike Simonsen has an answer to that mystery, too. “The most popular model to explain the secondary is that of a dark, opaque, relatively thick disk around a low-mass single star or a close binary. Differences in the shape of the particular eclipses could be explained by changes in both the inclination of the disc to the line of sight, and the tilt of its cross-section to the direction of motion.
The majority of the eclipses exhibit five repeatable phases that can be explained if the secondary is a disk shaped object with a gap in the center, like a giant cosmic donut. First, atmospheric and real ingress, where the dusty disk begins to obscure the light from the primary star, and then obscures it more fully as thicker, more opaque material blocks the light from the primary. Then a sloped-bottom transit, as the primary shines through the hole in the donut as it passes in front of the star. Then finally, real and atmospheric egress, as the disc moves away from in front of the primary star. The unique, flat-bottomed eclipse observed in 1969, can be explained by a nearly edge-on, non-tilted eclipse of the primary by the disc.
The color filter observations from the last eclipse show two increases in blue light (blue maxima) about 9 days before and after mid-eclipse. These subtle increases can be explained by the primary being a rapidly rotating Be star. These stars are darker around the equator and bluer at the poles. The reason there are two blue maxima can be explained if the disc is divided into two parts by a transparent gap. Spectroscopic observations show that the eclipsed component is a rapidly rotating Be star.”
Does this answer all the questions about EE Cephei? No. That’s the purpose of this article… More observations are needed and so is the help of all amateur astronomers ready and willing to take on the task. According to Mike, “The issue is far from settled. The light and color variations may have more to do with the different opacities in different parts of the disk. And here is where you can help write the story of this mysterious object. The next eclipse of EE Cephei starts right now. Mid-eclipse is predicted for January 14-15, 2009. The critical time to catch the blue maximums will fall between January 2nd and 27th. The longest eclipse lasted 60 days, so early December is the time to start taking data on this star, and observations should continue through the end of February.
If you have a CCD equipped with one or more science filters (UBVRI), astronomers at AAVSO will be very anxious to have you submit your data. If you are a visual observer, you can submit data on this eclipse also. EE Cep is normally a 10.8 magnitude star, and fades to anywhere from 11.5 to 12.5V. Thus it is easily observed with a telescope of 4” or more. Comparison charts for this star can be downloaded from the AAVSO’s Variable Star Plotter (VSP). There is a handy one page instruction for using VSP linked right from the top of that page.”
So, what are you waiting for? Here’s your chance to practice some serious astronomy!
