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FRIENDS OF THE PLANETARIUM NEWSLETTER – SEPTEMBER 2010
Our Mid-Winter lecture series was so popular that we are repeating it in September. The dates and
topics are: The Secret Lives of Stars on the 14th, Our Amazing Solar System on the 21st, and Galaxies
and Beyond on the 28th. The lectures start at 7:00 pm. and are $10 each or all three for $25. Bookings
can be made by calling or sending an email to the Planetarium.
Two guest lecturers will also be doing presentations at the Planetarium over the next few weeks. Peter
McLeish from Canada will be talking about Red Sprites and other unusual atmospheric phenomena. His
talk is Saturday, Sept. 4. Peter has presented his findings to science centers around the world. Our
second guest is Gordon Hudson, President of the Wellington Astronomical Society. Gordon is an expert
in telescope restoration. His talk on October 1st will describe some of the fantastic instruments that
Gordon has worked on. Gordon’s visit is supported in part by the Gifford-Eiby Lecture Fund, which is
managed by the Royal Astronomical Society of New Zealand. Both talks begin at 7 pm. Bookings are not
required for either lecture and entry is a gold coin donation.
The Sun is certainly beginning to awake from its quiet phase. Several large sunspots have emerged and
solar flares are becoming more frequent. Last month a flare was launched directly towards the Earth
which resulted in some spectacular auroral viewing. Unfortunately none of it was visible from Hawkes
Bay. Here is an image taken by the Solar Dynamics Observatory spacecraft just as the flare was leaving
the Sun’s upper atmosphere.
More interesting objects are being studied as robotic probes and new space telescopes explore our
solar system and beyond to other planetary systems. The European Space Agency's Rosetta spacecraft
has beamed back close-up photographs of asteroid Lutetia, an ancient, cratered relic from the dawn of
the solar system. Scientists are abuzz about the stunning images, which reveal a worldlet of haunting,
alien beauty. Asteroid Lutetia has been a target of interest
among astronomers for many years. It is one of the largest
asteroids in the solar system and has a strange spectrum of
reflected light that doesn't look quite like any other asteroid.
This photo was taken at closest approach, just over 3000 km.
When the opportunity presented itself for Rosetta to pay a visit
en route to its prime target, comet 67P/ChuryumovGerasimenko in 2014, mission planners couldn't pass it up.
Much further afield, astronomers have discovered the most massive
stars known, including one at more than 300 times the mass of our
Sun; double the size that scientists thought heavyweight stars could
reach. These colossal stars are millions of times brighter than the
sun and shed mass through very powerful winds. A European
research team discovered the massive stars inside a cluster of young,
massive and hot stars called RMC 136a, more commonly referred to
as simply R136, located within the Tarantula Nebula. This nebula is
found in the Large Magellanic Cloud, a neighboring galaxy that is 165,000 light-years away. Astronomers
found several stars with scorching hot surface temperatures of over 39,700 degrees Celsius, which is more
than seven times hotter than the sun. The stars are also tens of times larger and several million times brighter.
The researchers’ findings suggest that a number of these stars were greater than 150 solar masses at birth. In
fact, the star R136a1, which is located in the R136 cluster, is the most massive star ever found. Its current
mass is approximately 265 solar masses, and its estimated birth weight was as much as 320 times that of our
sun. R136a1 also has the highest luminosity of any star found to date, nearly 10 million times greater than the
sun. From the time of their birth, these massive stars produce outflows, such as powerful winds, which
eventually reduce their mass, researchers said.
They used a combination of instruments on
the European Southern Observatory's Very
Large Telescope, in addition to archival
data from the Hubble Space Telescope, to
study the stellar nurseries. Detecting the
ultra-heavy stars within them requires the
sharp resolving power of the Very Large
Telescope's infrared instruments.
The stellar discovery, which represents the
first time that these hulking stars were
individually identified, could help
astronomers understand the behavior of
massive stars, and how large they can be at
birth. This comparison image gives you
some idea of how massive these newly discovered behemoths are, compared to the more common gardenvariety stars like our Sun.
And finally, from our “Things That Go Bump in the Night” department comes this blast from space. A
record-breaking gamma ray burst from beyond the Milky Way temporarily blinded the X-ray eye on
NASA's Swift space observatory. The X-rays traveled through space for 5-billion years before slamming
into and overwhelming the space-based telescope. This mega burst, named GRB 100621A, is the
brightest X-ray source that Swift has detected since the observatory began X-ray observation in early
2005.
Receipts are enclosed for those who have renewed their membership. Thanks again for your support.