South African astronomers, together with collaborators from Moscow have discovered Luminous Blue Variable star. A very rare sighting as the star is very old and may soon blow apart causing a supernova explosion, one of the most powerful explosions in the Universe.
Astronomer Dr A. Kniazev from the South African Astronomical Observatory (SAAO), together with collaborators from the Lomonosov Moscow State University Dr V. Gvaramadze and Dr L. Berdnikov, has recently discovered a new example of an incredibly rare kind of star known as a Luminous Blue Variable star (LBV). Out of the billions of stars mapped in our skies, only sixteen confirmed Luminous Blue Variable stars are known to date. The star, named WS1, is the latest addition to this rare group of stars. LBV stars are of interest to astronomers because they are extremely old stars which may soon die and blow apart in a supernova explosion, one of the most powerful explosions in the Universe.
Just like humans, stars do not live forever. Once their fuel has run out they stop shining and die. Stars that are much more massive than the Sun end their lives in powerful supernova explosions which can outshine all the other billions of stars in their galaxy put together. We never know when or where one of these explosions will take place but we can keep an eye on those stars most likely to go supernova in the near future: Luminous Blue Variable stars. Luminous Blue Variables (LBVs) represent a stage in the evolution of very massive stars towards the end of their life. For stars with initial masses of between 20-25 times that of our Sun the LBV stage occurs just before the star dies in a spectacular supernova explosion. For even more massive stars, they pass through the LBV phase slightly earlier in their lifetimes, but those stars too will eventually die in a supernova explosion.
LBV stars are much hotter and therefore more luminous than our Sun. They are some of the most luminous stars known, with brightnesses ranging from 250,000 to 1 million times brighter than our Sun. As a consequence of their high mass they evolve very quickly and have – astronomically speaking – short lifetimes. LBV type stars have a total lifetime of around a few million years and spend much less than one million years in the LBV phase of their evolution. The LBV phase can be thought of as a “stellar retirement” for the most massive stars. The Sun for comparison has a total lifetime of around 9 billion years. Because the LBV phase is so short-lived you have to be incredibly lucky to catch a star at the LBV stage of its life. This explains why they are so rare compared with other types of star.
LBV stars are losing vast amounts of mass as their upper atmosphere streams off into space in a so-called “stellar wind”. These stars undergo random outbursts at their surfaces, spewing their outer atmosphere into space. These outbursts cause variations in their brightness which is one of the key observational signatures of such a star. Another consequence of their immense mass loss is the formation of a bipolar or circular nebula, or cloud, around the star composed of material that has been lost from the star’s atmosphere. These nebulae are found enveloping approximately 70% of confirmed LBV stars. Eta Carinae is a famous and well studied example of a LBV star with a beautiful bipolar nebula.
As most LBVs are enshrouded in a nebula, astronomers often look for possible LBV candidates by searching for such nebulae. In the case of WS1, Kniazev and collaborators were alerted to the possibility that the star could be a LBV because they found in 2011 that it is surrounded by a circular shell of material that emits light at infra-red wavelengths. This prompted them to make follow up optical observations of the central star to confirm whether or not the star was a LBV. In 2011, using the Southern African Large Telescope (SALT) they obtained a spectrum of the star (akin to a fingerprint) and found features in the spectrum typically associated with LBV type stars. However, this information was not sufficient to confirm whether WS1 was indeed a LBV. To do this, astronomers needed to observe the star over a long time period to confirm whether its variability in brightness and in its spectral features matched that expected from a LBV type star. Kniazev and collaborators continued to observe WS1 between 2013 and 2014 using the SALT telescope to look for changes in the star’s spectrum. They also monitored the star’s brightness between 2011 and 2014 using the South African Astronomical Observatory’s 1.9 m telescope and combined their observations with publicly available data spanning over forty years.
By combining the information from all their observations they found that WS1 did indeed exhibit all the observational characteristics of a LBV type star and concluded that WS1 is an incredibly rare Luminous Blue Variable star.
“We were very lucky to discover major spectral and brightness changes in WS1 without having to wait for too long”, says Kniazev. “With this discovery, we unambiguously proved the LBV status of this star. We expect that subsequent spectral analysis will allow us to determine fundamental parameters of WS1, for example its temperature and luminosity. We also hope to find more bona fide LBVs using SALT, which will help us to understand better the evolution of LBV type stars and their relation to other types of massive, old stars.”
This discovery, published as a Letter to Monthly Notices of the Royal Astronomical Society brings the total number of LBV stars known to date to sixteen.
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Prepare your cam to capture the Blood Moon
On 27 July 2018, South Africans can witness a total lunar eclipse, as the earth’s shadow completely covers the moon.
Also known as a blood or red moon, a total lunar eclipse is the most dramatic of all lunar eclipses and presents an exciting photographic opportunity for any aspiring photographer or would-be astronomers.
“A lunar eclipse is a rare cosmic sight. For centuries these events have inspired wonder, interest and sometimes fear amongst observers. Of course, if you are lucky to be around when one occurs, you would want to capture it all on camera,” says Dana Eitzen, Corporate and Marketing Communications Executive at Canon South Africa.
Canon ambassador and acclaimed landscape photographer David Noton has provided his top tips to keep in mind when photographing this occasion. In South Africa, the eclipse will be visible from about 19h14 on Friday, 27 July until 01h28 on the Saturday morning. The lunar eclipse will see the light from the sun blocked by the earth as it passes in front of the moon. The moon will turn red because of an effect known as Rayleigh Scattering, where bands of green and violet light become filtered through the atmosphere.
A partial eclipse will begin at 20h24 when the moon will start to turn red. The total eclipse begins at about 21h30 when the moon is completely red. The eclipse reaches its maximum at 22h21 when the moon is closest to the centre of the shadow.
David Noton advises:
- Download the right apps to be in-the-know
The sun’s position in the sky at any given time of day varies massively with latitude and season. That is not the case with the moon as its passage through the heavens is governed by its complex elliptical orbit of the earth. That orbit results in monthly, rather than seasonal variations, as the moon moves through its lunar cycle. The result is big differences in the timing of its appearance and its trajectory through the sky. Luckily, we no longer need to rely on weight tables to consult the behaviour of the moon, we can simply download an app on to our phone. The Photographer’s Ephemeris is useful for giving moonrise and moonset times, bearings and phases; while the Photopills app gives comprehensive information on the position of the moon in our sky. Armed with these two apps, I’m planning to shoot the Blood Moon rising in Dorset, England. I’m aiming to capture the moon within the first fifteen minutes of moonrise so I can catch it low in the sky and juxtapose it against an object on the horizon line for scale – this could be as simple as a tree on a hill.
- Invest in a lens with optimal zoom
On the 27th July, one of the key challenges we’ll face is shooting the moon large in the frame so we can see every crater on the asteroid pockmarked surface. It’s a task normally reserved for astronomers with super powerful telescopes, but if you’ve got a long telephoto lens on a full frame DSLR with around 600 mm of focal length, it can be done, depending on the composition. I will be using the Canon EOS 5D Mark IV with an EF 200-400mm f/4L IS USM Ext. 1.4 x lens.
- Use a tripod to capture the intimate details
As you frame up your shot, one thing will become immediately apparent; lunar tracking is incredibly challenging as the moon moves through the sky surprisingly quickly. As you’ll be using a long lens for this shoot, it’s important to invest in a sturdy tripod to help capture the best possible image. Although it will be tempting to take the shot by hand, it’s important to remember that your subject is over 384,000km away from you and even with a high shutter speed, the slightest of movements will become exaggerated.
- Integrate the moon into your landscape
Whilst images of the moon large in the frame can be beautifully detailed, they are essentially astronomical in their appeal. Personally, I’m far more drawn to using the lunar allure as an element in my landscapes, or using the moonlight as a light source. The latter is difficult, as the amount of light the moon reflects is tiny, whilst the lunar surface is so bright by comparison. Up to now, night photography meant long, long exposures but with cameras such as the Canon EOS-1D X Mark II and the Canon EOS 5D Mark IV now capable of astonishing low light performance, a whole new nocturnal world of opportunities has been opened to photographers.
- Master the shutter speed for your subject
The most evocative and genuine use of the moon in landscape portraits results from situations when the light on the moon balances with the twilight in the surrounding sky. Such images have a subtle appeal, mood and believability. By definition, any scene incorporating a medium or wide-angle view is going to render the moon as a tiny pin prick of light, but its presence will still be felt. Our eyes naturally gravitate to it, however insignificant it may seem. Of course, the issue of shutter speed is always there; too slow an exposure and all we’ll see is an unsightly lunar streak, even with a wide-angle lens.
On a clear night, mastering the shutter speed of your camera is integral to capturing the moon – exposing at 1/250 sec @ f8 ISO 100 (depending on focal length) is what you’ll need to stop the motion from blurring and if you are to get the technique right, with the high quality of cameras such as the Canon EOS 5DS R, you might even be able to see the twelve cameras that were left up there by NASA in the 60’s!
How Africa can embrace AI
Currently, no African country is among the top 10 countries expected to benefit most from AI and automation. But, the continent has the potential to catch up with the rest of world if we act fast, says ZOAIB HOOSEN, Microsoft Managing Director.
To play catch up, we must take advantage of our best and most powerful resource – our human capital. According to a report by the World Economic Forum (WEF), more than 60 percent of the population in sub-Saharan Africa is under the age of 25.
These are the people who are poised to create a future where humans and AI can work together for the good of society. In fact, the most recent WEF Global Shapers survey found that almost 80 percent of youth believe technology like AI is creating jobs rather than destroying them.
Staying ahead of the trends to stay employed
AI developments are expected to impact existing jobs, as AI can replicate certain activities at greater speed and scale. In some areas, AI could learn faster than humans, if not yet as deeply.
According to Gartner, while AI will improve the productivity of many jobs and create millions more new positions, it could impact many others. The simpler and less creative the job, the earlier, a bot for example, could replace it.
It’s important to stay ahead of the trends and find opportunities to expand our knowledge and skills while learning how to work more closely and symbiotically with technology.
Another global study by Accenture, found that the adoption of AI will create several new job categories requiring important and yet surprising skills. These include trainers, who are tasked with teaching AI systems how to perform; explainers, who bridge the gap between technologist and business leader; and sustainers, who ensure that AI systems are operating as designed.
It’s clear that successfully integrating human intelligence with AI, so they co-exist in a two-way learning relationship, will become more critical than ever.
Combining STEM with the arts
Young people have a leg up on those already in the working world because they can easily develop the necessary skills for these new roles. It’s therefore essential that our education system constantly evolves to equip youth with the right skills and way of thinking to be successful in jobs that may not even exist yet.
As the division of tasks between man and machine changes, we must re-evaluate the type of knowledge and skills imparted to future generations.
For example, technical skills will be required to design and implement AI systems, but interpersonal skills, creativity and emotional intelligence will also become crucial in giving humans an advantage over machines.
“At one level, AI will require that even more people specialise in digital skills and data science. But skilling-up for an AI-powered world involves more than science, technology, engineering and math. As computers behave more like humans, the social sciences and humanities will become even more important. Languages, art, history, economics, ethics, philosophy, psychology and human development courses can teach critical, philosophical and ethics-based skills that will be instrumental in the development and management of AI solutions.” This is according to Microsoft president, Brad Smith, and EVP of AI and research, Harry Shum, who recently authored the book “The Future Computed”, which primarily deals with AI and its role in society.
Interestingly, institutions like Stanford University are already implementing this forward-thinking approach. The university offers a programme called CS+X, which integrates its computer science degree with humanities degrees, resulting in a Bachelor of Arts and Science qualification.
Revisiting laws and regulation
For this type of evolution to happen, the onus is on policy makers to revisit current laws and even bring in new regulations. Policy makers need to identify the groups most at risk of losing their jobs and create strategies to reintegrate them into the economy.
Simultaneously, though AI could be hugely beneficial in areas such as curbing poor access to healthcare and improving diagnoses for example, physicians may avoid using this technology for fear of malpractice. To avoid this, we need regulation that closes the gap between the pace of technological change and that of regulatory response. It will also become essential to develop a code of ethics for this new ecosystem.
Preparing for the future
With the recent convergence of a transformative set of technologies, economies are entering a period in which AI has the potential overcome physical limitations and open up new sources of value and growth.
To avoid missing out on this opportunity, policy makers and business leaders must prepare for, and work toward, a future with AI. We must do so not with the idea that AI is simply another productivity enhancer. Rather, we must see AI as the tool that can transform our thinking about how growth is created.
It comes down to a choice of our people and economies being part of the technological disruption, or being left behind.