April 8th, 2010

[BRIEF NOTE] On Epsilon Aurigae

A very interesting discovery has been made in regards to the star Epsilon Aurigae. The fifth-brightest star in the constellation Auriga by Beyer designation and some two thousand light years away, for nearly two centuries astronomers have been aware that something's odd with this white giant star.

Although the star is visible to the naked eye, Johann Fritsch's 1821 observations suggest he was the first to notice that the system was a variable star. However, the system wasn't sufficiently observed until German mathematician Eduard Heis and Prussian astronomer Friedrich Wilhelm Argelander began observing it once every few years, from 1842 to 1848. Both Heis' and Argelander's data revealed that the star had become significantly dimmer by 1847, attracting the full attention of both men at that point. Epsilon Aurigae had brightened significantly, and had returned to "normal," by September of the next year. As Epsilon Aurigae attracted more attention, more and more data were compiled. The observational data revealed that Epsilon Aurigae did not just vary over a long period, but also experienced short-term variations in brightness as well. Later eclipses took place between 1874 and 1875 and, nearly thirty years later, between 1901 and 1902.


Why did Epsilon Aurigae dim? Even back in the early 20th century, the consensus was that Epsilon Aurigae's light was being blocked by another star which, in orbiting it, blocked out its light from terrestrial observers. In the middle of the presumed eclipse, light did spike upwards when the star should have been in complete blackness. But what sort of star was it that was invisible from Earth at the same time that it seemed to block the primary star's light? It turns out that Epsilon Aurigae A is orbited by a dust-shrouded bright blue star that happens to orbit Epsilon Aurigae A edge-on as seen from Earth. Andrew Moseman summarized at 80 Beats.

Epsilon Aurigae is a star system about 2,000 light years from Earth. Astronomers have been able to see it for nearly two centuries, and noticed that it dims every 27 years or so. It made sense to assume that they were dealing with a binary star system, with a larger primary star and a smaller secondary star circling around the first. But that didn’t answer all their questions. Why, for instance, did the primary star normally appear dimmer than it should? And if there is a smaller star orbiting the main star, why can’t we see it? To explain that, astronomers developed the unlikely theory that a thick disk of dust was orbiting the smaller star in the same plane as the smaller star’s orbit of the larger star [UPI].

Monnier says he first felt there was a slim probability that this explanation—a secondary star shrouded in dust—was true. To find out for sure, Monnier and his colleagues needed to catch the eclipse when the smaller star passed in front of the larger, and capture really telling images. That’s just what they did. The astronomers used the Michigan Infra-Red Combiner instrument to combine the light entering four telescopes at the CHARA array at Georgia State University. The effect is a virtual telescope that is much larger than its four constituents [Space.com].

The results, published in Nature, were staggering to Monnier. Despite the improbability of the explanation, there was indeed a “thin, dark, dense, but partially translucent cloud” passing in front of the star in the infrared pictures. Monnier says: “It kind of blows my mind that we could capture this. There’s no other system like this known. On top of that, it seems to be in a rare phase of stellar life. And it happens to be so close to us. It’s extremely fortuitous” [Space.com].



As Wikipedia notes, "[t]he two entities eclipse each other every 27.1 years, and each eclipse lasts approximately two years. Midway through the eclipse, the system brightens slightly. This implies the presence of an opening in the center of the disk that may be filled with a single star or a second binary system. The F-type supergiant and the dust disk are nearly thirty AU apart, which is approximately the distance of the planet Neptune from the Sun."

Nico Camargo's illustration is fantastic.

Epsilon Aurigae, eclipsed


Elsewhere in the Discover blogosphere, one of the co-observers commented with glee about the process of discovery.

The extraordinary thing to me about observational astronomy was always how you could put together an apparently baroque model of some complicated system, just on the basis of a precious few data points, and yet have some degree of confidence that you were on the right track. Reality is very constraining. So in some perverse sense, it almost seems like cheating to actually take pictures of the thing. Where’s the fun in that? (Of course it’s a great deal of fun.)


An age of miracles and wonders, people.

[MUSIC] Rita MacNeil, "Working Man"

The music of Rita MacNeil is not the sort of music that I listen to, not usually, not at all as a point of fact.



Rita MacNeil is a Canadian cultural figure of some note, a woman born in the Atlantic Canadian province of Nova Scotia, who achieved significant chart success in the 1980s and 1990s as a middle-of-the-road country-folk singer, not only in Canada but internationally: she had three albums at once on the Australian charts, even a #11 on the British charts in 1990 for "Working Man", originally released in 1989. I'm not that surprised that "Working Man" was such a hit in the United Kingdom, at the end of the Thatcher era; its subject certainly dealt intimately with one of the central issues of the Thatcher period.

It’s a working man l am
And I’ve been down under ground
And I swear to God if l ever see the sun
Or for any length of time
I can hold it in my mind
I never again will go down under ground

At the age of sixteen years
Oh he quarrels with his peers
Who vowed they’d never see another one
In the dark recess of the mines
Where you age before your time
And the coal dust lies heavy on your lungs


Rita MacNeil's native Cape Breton entered the industrial era as Canada's leading coal province, miners coming not only from all over Atlantic Canada but from all over the North Atlantic world--Jews, Lebanese, Ukrainians, Barbadians--to constitute a tight-knit working class culture with few parallels in the more traditional areas of Atlantic Canada but with many parallels in the tight-knit coal miners' cultures to be found elsewhere in the world: Wales, Appalachia, Silesia, the Donetsk Basin. Life for the coal miners' community was difficult, with the sorts of appalling safety conditions that regularly results in terrible catastrophes--China's long slew of mine disasters, or more recent events in Appalachia, come quickly to mind--and coal miners' families often living in poverty in ill-serviced company towns. It's not surprising, really, that industrial Cape Breton became one of the major centres of working-class radicalism in Canada, much like its counterparts elsewhere in North America and Europe. Like many of these areas, coal mining in Cape Breton entered a steep post-war decline as cheaper and better sources of coal became available, not withstanding activist workers and government intervention. Thatcher crushed the coal miners through political action; Cape Breton dealt with its coal mining industry through slow, hopeless, managed decline.

With the mines' closure in 2001, the coal mining culture in Industrial Cape Breton has dissipated, perhaps falling prey to the sort of slow-motion dissolution of communities, as mass unemployment and general hopelessness takes hold, described here that hit the coal-mining areas of the United Kingdom, and likely others. Life for these people is almost certainly safer than when the mines were open, but it strikes me as somewhat worrisome that we're so quickly forgetting about it, in truth, and rather sad that the strong sense of identity and community associated with that old life which at least gave people hope for the future is gone. Working-class sufferings aren't only limited to Appalachian coal mines, you know.

[DM] "On the new wave of Icelandic emigrants"

I've a post up taking a look at the new wave of Icelandic emigrants leaving their country post-bust. Although things are being exaggerated--a goodly share of the people who left have been recent immigrants, temporary or otherwise, and many who have left are doing so for neighbouring countries--the country certainly has to cope with a serious brain drain problem.

[LINK] "NASA-Funded Research Suggests Venus is Geologically Alive"

Thanks to james_nicoll for pointing me in the direction of this NASA press release. The European Space Agency's Venus Express probe is quite capable, unsurprisingly.

For the first time, scientists have detected clear signs of recent lava flows on the surface of Venus.

The observations reveal that volcanoes on Venus appeared to erupt between a few hundred years to 2.5 million years ago. This suggests the planet may still be geologically active, making Venus one of the few worlds in our solar system that has been volcanically active within the last 3 million years.

The evidence comes from the European Space Agency's Venus Express mission, which has been in orbit around the planet since April 2006. The science results were laid over topographic data from NASA's Magellan spacecraft. Magellan radar-mapped 98 percent of the surface and collected high-resolution gravity data while orbiting Venus from 1990 to 1994.

Scientists see compositional differences compared to the surrounding landscape in three volcanic regions. Relatively young lava flows have been identified by the way they emit infrared radiation. These observations suggest Venus is still capable of volcanic eruptions. The findings appear in the April 8 edition of the journal Science.

[. . .]

The volcanic provinces, or hotspots, on which Smrekar and her team focused are geologically similar to Hawaii. Scientists previously detected plumes of hot rising material deep under Venus' surface. Those plumes are thought to have produced significant volcanic eruptions. Other data from the planet suggest that volatile gases commonly spewed from volcanoes were breaking down in its atmosphere. The rate of volcanism will help scientists determine how the interior of the planet works and how gases emitted during eruptions affect climate.

Something is smoothing Venus' surface, because the planet has only about 1,000 craters, a relatively small amount compared to other bodies in our solar system. Scientists think it may be the result of volcanic activity and want to know if it happens quickly or slowly. The Venus Express results suggest a gradual sequence of smaller volcanic eruptions as opposed to a cataclysmic volcanic episode that resurfaces the entire planet with lava.
</blockquote>

Jupiter's moon Io has Earth-like volcanic activity, while Mars is suspected of being active at some low level. Cryovulcanism--volcanic processes making use of water and other ices, in low-temperature environments like those in the outer Solar System--is suspected to exist on Saturn's moon Titan, among other possible worlds.

[LINK] "Igor Kenk wants his bikes back"

I blogged back in the summer of 2008 about Igor Kenk, the owner of a used bike shop in Toronto who was arrested then in connection to his central role in the theft of some three thousand bikes, secreted in a dozen different locations across Toronto. He's since been convicted, sentenced to sixteen months in jail, while those of his bikes that haven't been returned to their owners are being given to children in poor communities across Ontario. To me, what Jennifer Yang distributed in a writes in the Toronto Star suggests that Kenk's bike theft was less a case fo desiring to profit personally from crime and more a case of spectacular hoarding.

Igor Kenk misses his bikes.

In an unexpected turn of events, the convicted bike-nabber showed up at the Cabbagetown Youth Centre on Monday where nearly 2,000 bikes seized from his property in 2008 were being donated to inner-city youth.

Volunteers were hauling some 1,830 bicycles and parts into the basement for temporary storage when a man in a baby blue track suit showed up and began asking how he could purchase some of the bikes.

The man then offered to help rebuild some of the bicycles before leaving his phone number and a name: Igor.

“My jaw dropped. I couldn’t believe it,” said Mary, a centre volunteer who declined to give her last name. “It almost seems like he was visiting his children or something and had a restraining order (against him).”

Kenk claims to have stumbled upon the community event, only realizing later that the bikes being donated originated from his stash.

A peevish Kenk told the Star he still considers the bikes his property and called it “completely and utterly irresponsible” to have them “thrown in the garbage.”

“This is like (taking) Ferrari or Lamborghini cars, throwing them as scrap,” Kenk said.

He added, “Of course they’re my bikes. Think of them as my puppies ...”

“I would love to buy some of my property back.”

[. . .]

Kenk complained he was strong-armed into forfeiting the bikes to the province. Under the Civil Remedies Act, the attorney general can ask a civil court to freeze, take possession of, or forfeit property that is deemed to result from unlawful activity.

Before being forfeited to the province, the bikes were held by the Toronto police’s property and evidence unit — a task that was “logistically challenging to say the least,” according to manager Brenda Radix. Police say as many as 900 of Kenk’s bikes have since been returned to their rightful owners.

[LINK] "A Toronto neighbourhood without children"

Over at the Globe and Mail, Anna Mehler Paperny took a look at how "[t]he city and developers want breeders and their broods to start populating condo towers, but it's an uphill battle." The condo boom, it seems, downsides owing to the cost of units that mightn't have come to mind.

Carol Finlay's friends and family think she's crazy. A neglectful would-be mother. An urban masochist.

Her audacious proposal? To move downtown to raise a family.

“[They say,] ‘You can't raise a family. … That would be neglectful to children … it's not enough space to raise children, it's dangerous.' ”

Ms. Finlay, 29, and her husband Charlie are moving in August from North York to a loft near the corner of Queen and Dovercourt, which they hope to convert into a three-bedroom condo. “Ninety per cent of our friends are going in the opposite direction.

“[But] our life is in Toronto and it didn't make sense to us to spend so much of our time commuting,” Ms. Finlay says. “In North York we weren't part of the community there as much as we would like to be. … We would like to start a family and that becomes even more important to us.”

[. . .]

For the most part, the city is on board with the onset of a hyper-dense metropolis of vertical neighbourhoods. But the people buying those $600,000 condos are young singles and couples and, to a lesser extent, retirees. This migration upward coincides with an exodus of families from the downtown core. In the 2006 census, children under 15 made up only 8.4 per cent of Trinity-Spadina's population, compared with 16.3 per cent in the rest of Toronto.

The city is trying to change that. For months, Councillor Adam Vaughan has been working with developers on a social engineering project: to lure families into gleaming condominium boxes in the sky.

The to-do list is deceptively simple – families need space and services with an affordable price tag attached. Achieving that in one of the priciest real-estate markets in Canada is another story altogether.

It has been done elsewhere – notably Vancouver, which has seen its population of downtown children more than quintuple since 1986.

But developers shy away from the drastic measures and the minimum three-bedroom requirement Mr. Vaughan would like to see – they are skeptical as to whether this social-planning ploy will work.

[. . .]

The city's official plan to house more people in the downtown core calls for increasing density to take eco-conscious advantage of scarce urban space. But if Toronto's downtown neighbourhoods are going vertical, argues Mr. Vaughan, those 30-storey elevators should have kids inside.

“You can't sustain a city with a monoculture; you can't segregate singles from families and seniors from young people. What we need when we build these buildings is to build vertical neighbourhoods, and that means we need to sustain economic diversity and social diversity.”


For what it's worth, I quite like the Queen and Dovercourt area, but then, I'm not seeking to raise a family, either.

Question: Is this core-periphery contrast one of the emerging themes of Toronto's growing internal divisions and contrasts?