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The SOCIETY for POPULAR ASTRONOMY
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Electronic News Bulletin No. 185 2005 November 20
=====================================================


Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is Britain's liveliest astronomical society, with
members all over the world. We accept subscription payments online
using our secure site and can take credit and debit cards. You can
join or renew via a secure server or just see how much we have to
offer by visiting http://popastro.c.topica.com/maaeewUabmdX5ciD1pRb/

Philip's, a publisher of astronomy books and planispheres for the
amateur astronomer, is sponsoring this bulletin. For information on
Philip's titles see the end of this bulletin.


MORE ON THE OCTOBER 5-6 "BRIGHT METEORS" EVENT
By Alastair McBeath, SPA Meteor Section Director

Additional video results from Germany and Finland have confirmed the
weak, but unanticipated, bright meteor activity from a radiant at RA
10h48m, Dec +79 degrees, between roughly 17h-02h UT on October
5-6 now, as reported earlier in ENB 184. The likely peak remains
between circa 19h-20h UT then. My own examination of the October
radio observations in Radio Meteor Observation Bulletin 147 (October
2005; see http://popastro.c.topica.com/maaeewUabmdX6ciD1pRb/ suggested a mild
enhancement in about
40% of the viable datasets from about 17h-20h UT that night, with a
mean peak time of around 18:40 UT +/- 1 hour (however, the radio
results are mostly given in one-hour bins, so the apparent accuracy of
this timing is somewhat deceptive). The difference to the normal radio
meteor rates then was marginal in all but one of the positive sets of results,
and even that gave only a small, but more definite, showing. The nature of
the radio reports does support the general video findings - low rates of
predominantly brighter meteors.


DRACONIDS 2005 - RADIO RESULTS
By Alastair McBeath, SPA Meteor Section Director

Further details on the Draconid outburst of October 8-9, centred around
16h-17h UT then (as detailed in ENB 184), are now available, in the
form of the October RMOB radio results, which I have recently examined.
Half the viable datasets showed something marginally unusual then, all
from Europe. The mean peak time from those was about 16:30 UT +/- 1
hour, with a spread in at least mildly abnormal rates covering the interval
13h-22h UT on the same date. This pattern is asymmetric even after
considering the variable radiant elevation, suggesting a longer declining
"tail" to the outburst.

Interpreting the data further suggests there may have been two elements
to the Draconid event: a small proportion of "normal visual" meteors; and
a much larger very faint meteor component. The middle range of faint
visual to moderately faint radio meteors, was largely missing, apparently.
If this interpretation is right, it seems to confirm the early visual and radar
results, though the estimated mean peak radio time (remembering the
radio records are in hourly bins only) was slightly early compared to the
radar one, slightly late to the visual. This too might fit with the different
meteoroid components, assuming a small degree of mass-sorting, or
something similar, within the 2005 Draconid meteoroid stream filament.


OCTOBER 9-10 FIREBALL FOLLOW-UP
By Alastair McBeath, SPA Meteor Section Director

A third sighting of the October 9, 21:25 UT fireball has now been
received, from Wolverhampton. Unfortunately, no additional refinement
of the vague possible surface track in ENB 184 has yet been practical.


TAURID "SWARM" RETURN
By Alastair McBeath, SPA Meteor Section Director

It now seems clear that the Taurids did indeed produce enhanced bright
meteor activity from late October to early November this year, as
commented in the Special ENB for November 5. There are regrettably
few detailed meteor watch results available so far, but there have been
plenty of casual reports of somewhat heightened Taurid rates, and a
notable string of fireball sightings up to magnitude -15 or so, from almost
every night between October 26-27 to November 12-13 inclusive.
Fireball reports have come from the UK, the USA and various parts of
Europe, too many to list individually (at least 26 separate fireballs seem to
be represented in the observations now). It is not certain that all of these
were Taurids, but enough have been identified as such to leave little doubt
that many probably were. The most fireball-productive nights were
October 30-31 and 31-32 and November 2-3 to 5-6 inclusive. The best
-seen British event remains the November 3-4 event mentioned last time,
although due to a misreading of my notes, the time interval for that should
have been 22:40-22:50 UT, not the 20:40-20:50 UT I gave.

Anyone with further Taurid data to send - whether of a fireball (a meteor
of magnitude -3 or brighter), some bright meteors, a meteor watch,
imaging or radio observations - is invited to do so with all speed. Details
of what to report from visual watches and fireball sightings can be found
off the meteor homepage, at: http://popastro.c.topica.com/maaeewUabmdX7ciD1pRb/
.


NO NEW MARTIAN METEORS
By Alastair McBeath, SPA Meteor Section Director

Late October also brought a flurry of several new supposed meteor
recordings from the surface of Mars. Regular ENB readers may recall
we commented on the first definite recording of such a meteor in the
Special ENB for 2005 June 19. However, this latest batch have turned
out to be false trails, actually caused by cosmic rays striking the imaging
CCD chips at an angle. The cosmic ray flux is quite intense on Mars, as
its thin atmosphere allows many more through than at the Earth's surface.


LEONIDS 2005 - FIRST IMPRESSIONS
By Alastair McBeath, SPA Meteor Section Director

These are some very preliminary notes, based on just my own
impressions of activity on November 16-17, 17-18 and 18-19 so far, but
the Leonids seem to have produced quite healthy activity, despite the
bright Moon. Observed numbers have been up to 5 to 10 Leonids an
hour on all nights after 03:30 UT and on towards dawn. The Leonids I
saw on November 17-18 and 18-19 were also bright, and included
several fireballs. The best was at 03:58 UT on November 17-18, of
magnitude -6/-8, which left a 45-second train despite passing barely 30
degrees from the Moon! As the normal peak was not expected to be
visible from the UK on November 17 (see ENB 184), but another one
might be on November 20-21, it would seem well worth keeping a watch
in the hopes this type of activity may persist, or indeed even improve,
over the next couple of nights or so. Remember though that the Leonid
radiant can only be observed after 23h UT, and is still low until well after
midnight. Good luck, and clear skies!


COMET CONTAINS MORE DUST THAN ICE
ESA

Observations of Comet 9P/Tempel 1 made by the Rosetta spacecraft after
the Deep Impact collision suggest that, if Tempel 1 is at all typical,
comets are 'icy dirtballs' rather than 'dirty snowballs' as
previously believed. In July this year, the Deep Impact mission sent
an impactor probe to hit Tempel 1. The collision was expected to
excavate a crater with a diameter of about 100-125 metres and to eject
cometary material. It vaporised 4500 tons of water, but surprised the
investigators by releasing even more dust.

At a distance of about 80 million kilometres from the comet, Rosetta
observed before and after the impact and measured the water-vapour
content and the cross-section of the dust created by the impact. The
scientists could then work out the corresponding dust/ice mass ratio,
which is larger than one, so it looks as if Tempel 1 is composed more
of dust held together by ice, rather than made of ice contaminated
with dust. The scientists did not find evidence of enhanced outburst
activity of Tempel 1 in the days after the impact, suggesting that
impacts of meteoroids are not the cause of cometary outbursts, at
least in the case of Tempel 1.


NEW MOONS OF PLUTO
NASA

Astronomers have discovered that Pluto may have not one, but three
moons, which will make it the first body in the Kuiper Belt known to
have more than one satellite. The candidate moons, provisionally
designated S/2005 P1 and S/2005 P2, are approximately 27,000 miles
away from Pluto -- in other words, two to three times as far from
Pluto as Charon. They are tiny, with estimated diameters between 40
and 125 miles. Charon, for comparison, is about 730 miles in
diameter, while Pluto itself has a diameter of about 1410 miles.
The team plans to make follow-up Hubble observations in February to
confirm that the newly discovered objects are truly Pluto's moons.
Only after confirmation will the International Astronomical Union
consider permanent names for the objects.

The Hubble telescope's 'advanced camera for surveys' observed the two
new candidate moons on May 15. Three days later, Hubble looked at
Pluto again. The two objects were still there and appeared to be
moving in orbit around Pluto. A re-examination of older Hubble images
taken on 2002 June 14 has confirmed the presence of both P1 and P2
near the predicted locations based on the 2005 Hubble observations.
The team looked long and hard but unsuccessfully for other potential
moons around Pluto.


ETA CARINA'S COMPANION STAR OBSERVED
The Register

Researchers using the 'Far Ultraviolet Spectroscopic Explorer'
satellite (FUSE) have made a direct observation of Eta Carinae's
companion star. Astronomers have good indirect evidence that a
companion star exists, since they have observed a five-and-a-half-year
repetitive pattern of changes in the star's visual, X-ray, radio
and infrared emissions. Once every five and a half years, the X-rays
from the region disappear completely. Interestingly, Eta Carinae
itself is too cool to produce X-rays, but it has got a stellar wind
blasting particles into space at 300 miles per second. A collision
between that wind and a similar one from a companion star could
produce the observed X-rays. Eta Carinae is one of the most massive
stars in the Galaxy and is thought to be nearing the end of its life.
Its instability and odd quirks have made it one of the most studied
stars of the last few decades.

The astronomers turned FUSE to look at the star just before the
regular cessation of X-rays from the region. When the X-rays stopped,
there was also a noticeable drop-off in far-ultraviolet light, which
Eta Carinae is also too cool to produce. They concluded that when the
X-ray-emitting region is eclipsed, so too is the companion star. The
far-ultraviolet light must come directly from Eta Carinae's companion
star, the first direct evidence that it exists. The companion is
much hotter than Eta Carinae itself.


PLANETARY BUILDING BLOCKS
NASA

The Spitzer telescope has detected for the first time the building
blocks of planets around brown dwarfs, suggesting that such failed
stars probably operate the same planet-building process as proper
stars are supposed to do. There are tiny crystals and dust grains
circling five brown dwarfs located 520 light years away in the
constellation Chamaeleon. The crystals, composed of a green mineral
commonly found on Earth and known as olivine, are thought to be the
building blocks of planets.


GIANT STAR COLLAPSES INTO NEUTRON STAR
SPACE.com

Researchers say that a star 40 times the mass of the Sun collapsed to
form a neutron star instead of a black hole. Scientists previously
thought that when a massive star died and collapsed on itself, it had
no choice but to create a black hole. Now, new data from the Chandra
X-ray observatory suggest that massive stars can sometimes produce a
neutron star instead.

Researchers discovered the neutron star, about 12 miles in diameter,
in an extremely young cluster of stars. By estimating the age and
mass of the other stars in the cluster, the scientists were able to
determine that the neutron star's parent was at least 40 times the
mass of the Sun. Very massive stars evolve faster than less-massive
ones, so a star's mass can be estimated if its evolutionary stage is
known. Neutron stars and black holes are the end stages of a star's
life, so the stars that produced them must have been among the most
massive stars in the cluster.

When very massive stars evolve into neutron stars instead of black
holes, they have a greater influence on the composition of future
generations of stars. Instead of having most of its mass disappear
into a black hole, the star sends more than 95 per cent of its mass --
mostly metal-rich material from its core -- into the surrounding
space, which means that enormous amounts of heavy elements are put
back into circulation and can form other stars and planets.


MILKY WAY'S BLACK HOLE DOWNSIZED
Space.com

The black hole that is supposed to lie at the heart of our Galaxy is
now said to be much smaller than previously thought. A new estimate
made with the Very Long Baseline Array indicates that the diameter
of Sgr A*, as the object is known, is about 93 million miles --
equal to the distance between the Earth and the Sun. In theory
there is around a black hole a quasi-spherical surface known as the
event horizon, from within which no light or matter can emerge;
detecting it would be the ultimate proof that Sgr A* is indeed a
supermassive black hole. Event horizons have never been observed
directly, but astronomers think that they could be if a telescope's
resolution were high enough. A sufficiently high-resolution image
should reveal a dark circle -- a shadow caused by radiation from
behind the black hole falling into the event horizon. Surrounding the
shadow should be a bright ring of light caused by the deflection of
light rays that just manage to scrape past the event horizon.


REMAINS OF COPERNICUS BELIEVED EXCAVATED
AFP

Human remains excavated in a cathedral in northern Poland are very
likely those of the Renaissance astronomer Nicolas Copernicus,
according to archaeologists. The remains of a 70-year-old man were
dug up near the altar of the cathedral in Frombork where Copernicus
held the office of canon. A police laboratory in Warsaw used the
skull to make a virtual reconstruction of the man's face, which
resembled portraits of Copernicus, a key figure in the scientific
revolution of the 17th century with his heliocentric theory of the
Solar System. Archaeologists said that a scar on Copernicus' head,
visible in a portrait, corresponded to a mark near the eyebrow on
the skull. Copernicus lived from 1473 to 1543 and his best-known
work, On the Revolutions of the Heavenly Spheres, was published a
few days before his death and in 1616 was condemned by Pope Paul V
as being contrary to the Scriptures.


LIGHT FROM EARLY UNIVERSE
NASA

Scientists using the Spitzer space telescope say that they have
detected light that may be from the earliest objects in the Universe.
A 10-hour observation of an area in the constellation Draco by
Spitzer's infrared array camera showed a diffuse glow that may be from
Population III stars, a hypothesized class of stars thought to have
formed before all others. Theorists say that some of the first stars
may have been over a hundred times as massive as the Sun and extremely
hot, bright, and short-lived, each lasting only a few million years.
The ultraviolet light that they emitted would by now have been shifted
into the infrared by the Universe's expansion. The Spitzer
observation confirms a result from the Cosmic Background Explorer
satellite in the 1990s that suggested that there may be an infrared
background that could not be attributed to known stars. It also
supports a 2003 estimate, made by users of the Wilkinson Microwave
Anisotropy Probe, that stars first ignited 200--400 million years
after the Big Bang.


CHINA PLANS MOON-WALK FOR 2017
The Register

China is planning to send a manned mission to the Moon as early as
2017 to investigate the amount of helium-3 in the lunar soil. Chinese
space-agency planners say that they are now developing another four
spacecraft, with a view to building a permanent Chinese space station
and eventually going to the Moon. It plans to launch its next manned
mission in 2007, which could feature China's first space walk.


STAR EJECTED FROM LMC
ESO

A hot massive star moving at more than 700 km/s has been discovered in
the course of the Hamburg/ESO sky survey far out in the halo of the
Milky Way, towards the constellation Doradus. That is an unusual
place for such a star: massive stars are ordinarily found in the disc
of the Milky Way. Data obtained with the UVES instrument on the Very
Large Telescope in Chile show the star to be rather young and to have
a chemical composition similar to that of our Sun. The data also
reveal the high speed of the star. When astronomers calculated how
long it would take for the star to travel from the centre of our
Galaxy to its present location, they found that it would take more
than three times its age. Either the star is older than it appears or
it was born and accelerated elsewhere. Indeed, it lies closer to one
of the Milky Way satellite galaxies, the Large Magellanic Cloud (LMC),
located 160,000 light-years away from us, than to here. The
suggestion is that it could have reached its present position after
being ejected from the LMC.


JAPANESE ROBOT LOST
Yaboo.com

The Japan Aerospace Exploration Agency (JAXA) has reported that a
miniature robot, released by the Japanese space probe Hayabusa in the
course of its investigation of the small asteroid Itokawa, was lost
before it was able to land on the asteroid's surface. Itokawa, a
600m-long asteroid that travels in an orbit that takes it between the
Earth and Mars, is named after Hideo Itokawa, the father of Japan's
space exploration programme. It is currently around 290 million km
away from the Earth. Hayabusa, which was launched on 2003 May 9, has
been hovering over Itokawa for almost two months. Minerva, a
10-cm-long can-shaped robot, was designed to gather information on
Itokawa as part of a rehearsal for Hayabusa's own landing, scheduled
for November 19. Minerva's landing was to have been the first attempt
by Japan to send information-gathering equipment to an extra-
terrestrial object. Equipped with a camera and thermometers, Minerva
was meant to hop around Itokawa and send data such as surface
temperatures and images back to Earth via Hayabusa. A previous
attempt to land Minerva earlier this month was aborted owing to
technical problems.


PHILIP'S NEW TITLES:

Published this month:
Philip's The Sky at Night Volume 2 is the latest volume in Sir Patrick
Moore's series of essays written to accompany the BBC television
series of the same name. It tracks the most important developments in
astronomy, astrophysics and space exploration in the period from 2001
November to 2005 March -- £9.99
Philip's Stargazing 2006 by Heather Couper and Nigel Henbest.
Stargazing 2005 was a popular addition to Philip's astronomy list last
year, and the 2006 edition of this month-by-month practical guide to
the changing night sky is expected to be equally well received. - £6.99
Coming in December:
Philip's Solar System Guide by Peter Grego contains an abundance of
information and images, and is a practical and colourful introduction to
our corner of the Universe. It describes how to observe not only the
planets but also the Moon, Sun, comets, meteors, asteroids and other
objects found within our Solar System -- £9.99
Philip's Solar System Observer -- a brand-new pack for the amateur
Solar-System observer. It contains three essential items for exploring
and enjoying our corner of the Universe: Philip's Solar Observer's
Guide, Philip's Map of the Solar System and Philip's Solar System
Phenomena poster -- £12.99
For more information on those and other Philip's titles please visit
www.philips-maps.co.uk or call 020 7644 6935 for a catalogue.


Bulletin compiled by Clive Down

(c) 2005 the Society for Popular Astronomy


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