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                  The SOCIETY for POPULAR ASTRONOMY
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          Electronic News Bulletin No. 280   2010 January 17
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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 at our secure site and
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QUADRANTIDS 2010 - FIRST IMPRESSIONS
By Alastair McBeath, SPA Meteor Section Director

Initial reports arriving from various parts of the UK so far have suggested
that even where people had clearer skies on January 3-4, very sensibly
scarcely any observers were prepared to chance the often deadly icy
conditions underfoot to get to their observing sites, particularly when
coupled with the glare from the moonlit snow. 
However, there were a couple of casual fireball sightings, one each on
January 2-3 and 3-4, the second of which at least may have been a
Quadrantid, though a preliminary review of his video data by Enrico Stomeo
in Italy found just one fireball on January 2-3 or 3-4, a magnitude -9
sporadic at 02:08 UT on January 4. Enrico's results, plus more video data
from Bob Lunsford in California, USA (all kindly forwarded by Rich Taibi in
Maryland, unable to watch himself because of still more devastatingly cold
temperatures than those in Britain, and very high windchill), suggested
healthy Quadrantid activity on January
3 at least. Visually, including details helpfully submitted by North
American Meteor Network leader Mark Davis (NAMN; see
http://www.namnmeteors.org ), Quadrantid results have arrived from Tibor
Csorgei (Slovakia; NAMN), David Scanlan (England) and David Swann (Texas,
USA; NAMN). These suggested Zenithal Hourly Rates
(ZHRs) may have been around 80 +/- 30 from ~17:30-20:15 UT on January 3-4,
though the very low radiant from Europe then made it difficult to assess the
reliability of this finding, especially in the absence of the International
Meteor Organization's (IMO's) usual "live" shower webpage for the
Quadrantids this year.

Some radio-meteor notes posted on the IMO-News e-mailing list on January 5
by Japanese observer-analyst Hiroshi Ogawa indicated he had found a peak
around 16:00-18:00 UT on January 3. However, his analysis method has proven
somewhat controversial previously, as it is unclear how the various
disparate radio data have been combined into a single numerical value, plus
there have been occasions before when insufficient allowance had been made
for the varying sensitivities of the different radio systems involved, as
shower radiant elevations changed with time. Of the radio observers
reporting directly to us at present, also including Assistant Meteor
Director David Entwistle, only Jeff Brower in British Columbia, Canada, was
able to provide detailed radio-echo counts across the expected Quadrantid
maximum, while the radiant was at a useful elevation. These seemed to favour
a peak around 12h-15h UT on January 3 instead, but also gave an
interestingly healthy response around 18:00-19:00 UT then as well. 
Which was the true peak will likely only become clearer (if indeed that can
be achieved), once all the January radio results are in, hopefully by mid
February, plus any more visual or video data. See ENB 279 (
http://snipurl.com/u3plp  ) for the Quadrantid maximum predictions.

Some further notes, plus a graph of David's radio observations, are
available on the SPA's Observing Forum at: http://snipurl.com/u3plw  .
If anyone else has Quadrantid meteor data to submit, please send them along
as soon as possible!


LANTERNS CAUSE "NEW YEAR METEOR SHOWER" ALERT By Alastair McBeath, SPA
Meteor Section Director

An unexpectedly large number of reports of "fireballs" or a "meteor shower"
from New Year's night, beginning in the early evening of December 31, and
running through till about 00:30 UT on January 1, arrived from many parts of
the UK. After carefully examining all the information submitted, including
follow-up notes from some of the witnesses in the vaguer cases, no definite
meteor observations were found among them at all, only single or multiple
"sky lantern" releases. 
This came at the end of another general surge in reports of lanterns
mistaken for fireballs, beginning in mid-December. News was also received of
lifeboats being launched, and other emergency services wasting time and
effort, chasing nonexistent distress flares caused by some of the lanterns
in December, especially near coastal districts. We last discussed sky
lanterns in ENB 270 ( http://snipurl.com/u3qor ) during the summertime
plague of them, with advice on separating them from meteors and other moving
lights in the night sky. Some progress is being made in terms of improved
public education regarding them. 
For instance, one first-time witness who spotted a lantern in late December,
and reported it thinking it might have been a fireball, wrote back to say
they had realised it could not have been, after observing more identical
objects - lanterns - at New Year. On the other hand, a few of the reported
New Year objects were seen under cloudy skies, so clearly could not have
been meteoric at all. A lantern or two continued to be reported from the
first couple of days of January, but hopefully this latest deluge of the
things has now passed, barring the odd one, at least till the next holidays.
SPA Secretary Guy Fennimore has already warned on the Forum that Chinese New
Year is on February 14, also St Valentine's Day...


URSIDS 2009
By Alastair McBeath, SPA Meteor Section Director

As noted on December's monthly meteor webpage, the largely moonless Ursid
maximum was scheduled to fall between 13:30- 16:00 UT on December 22 (the
time the Earth passed closest to the node of the stream's parent comet,
8P/Tuttle), perhaps with another peak around 07:14 UT. ZHRs were expected to
be 10-15 or so. With neither timing favouring Britain, and December's
weather being remarkably poor, it is unsurprising no visual results arrived
from here, and the sole visual Ursid data came from NAMN watcher Tibor
Csorgei in Slovakia. However, Radio Meteor Observation Bulletin 197 for
December 2009 (RMOB; see http://www.rmob.org ) having recently been provided
by the kind offices of editor Chris Steyaert, a detailed analysis of the
shower's radio-behaviour has been possible. The list of RMOB observers
active in December included:

Enric Algeciras (Spain), Orlando Benitez (Canary Islands), Michael Boschat
(Nova Scotia, Canada), Jeff Brower (British Columbia, Canada), Willy Camps
(Belgium), Johan Coussens (Belgium), Gaspard De Wilde (Belgium), David
Entwistle (England), Karl-Heinz Gansel (Germany), Mike Otte (Illinois, USA),
Steve Roush (Arizona, USA), Wayne Sanders (British Columbia, Canada), Andy
Smith (England), Chris Steyaert (Belgium), Dave Swan (England), Istvan
Tepliczky (Hungary), Dirk Van Hessche (Belgium), Maarten Vanleenhove
(Belgium), Felix Verbelen (Belgium), John Wardle (England).

Radio-detectable Ursid activity was found primarily just on December 22, but
without an especially clear or strong radio signature from the shower,
perhaps indicative of the anticipated fairly normal ZHRs. There appeared to
have been a more active period from about 02h-12h UT then, with a likely
core from ~05h-09h UT (this was difficult to confirm exactly, because it
coincided with the diurnal sporadic peak for Europe, which usually occurs
for a couple of hours either side of 06h each day). 
Despite this, there was evidence for a brighter-meteor peak in the
07:00-08:00 UT data-bin from both Europe and North America, judging by the
increased numbers of longer-duration meteor echoes then. As there was no
sign of anything unusual after midday UT, this suggested the 07:14 UT peak
prediction was probably closer to reality than the later nodal-crossing
time. Graphs showing David Entwistle's radio Ursid results can be found on
the Observing Forum at:
http://snipurl.com/u3s4g  .


GEMINIDS 2009 UPDATE
By Alastair McBeath, SPA Meteor Section Director

Little has changed in respect of the visual results discussed in ENB 279,
but some fresh data have arrived from Karl Antier (France), Pam Foster
(Scotland), Jonathan Shanklin (England) and William Watson (New York, USA;
NAMN), along with the majority of December's radio observations in RMOB 197
(as noted, with the observers, in the Ursid report above). The radio
analysis found the Geminids produced especially good activity from around
23h UT on December 12 through to about 14h UT on December 14. Unfortunately,
the peaks within this general interval proved remarkably hard to pin-down
beyond this, but there were definite suggestions the overall better activity
fell between ~00h-08h UT on the 14th, and seemed strongest from about
00h-05h UT. However, it is difficult to be certain of this, because the
activity also showed another "peak" (if one less strong) around 04h-06h UT
on December 13. This interval on both dates was doubly awkward, as it
coincided with the European diurnal sporadic peak, and one of the better
North American radio-Geminid detection intervals. It was odd these findings
did not match especially well with the preliminary IMO visual data, which
suggested at least two main ZHR ~120-130 peaks on December 14, near 19h-20h
and 01h-02h UT, within a period of enhanced activity, ZHRs ~100+, lasting
from ~15:30 UT on December
13 to 20h UT on December 14. Given the strength of the visual activity too,
it was a little surprising to find quite a few of the radio datasets showed
a less-clear Geminid signature overall than might have been expected from
past results. Regrettably, why these seeming discrepancies should have been
present is not clear.

Despite this, a hearty "well done" goes to all our contributors from the
Geminid, Ursid and 2010 Quadrantid epochs, during a particularly difficult
winter for outdoor activities of any kind, let alone nocturnal astronomical
ones! We must hope conditions will be kinder as the new year proceeds.


MARS IN JANUARY
By Andrew Robertson, SPA Planetary Section Director

I have just taken over as the Planetary Section Director.  I will do a
profile of myself later, but in the meantime just want to remind everyone
that Mars is at opposition this month.  If you look due East late in the
evening you can't fail to notice a bright orange/red 'star' outshining any
other star (apart from Sirius) at magnitude -1.1, although to me it seems at
least as bright as Sirius owing to atmospheric extinction because of
Sirius's low altitude.  Mars reaches opposition on the 29th although it will
be closest to the Earth on the 27th, when it reaches a diameter of only
14".1, less than at many oppositions.  It culminates at 1.30 am this weekend
(16th/17th Jan) at an altitude of 58 degrees from my Latitude of 52 degrees
North, although it is at a healthy 40 degrees by 10pm.  It is currently
13".8 in diameter with a phase of 99%, so you will really need a power in
excess of x200 to start pulling out detail.  For diehard all-night observers
or those who want to get up in the early hours Saturn rises at 9.30 pm,
culminating at 3.30 am at an altitude of 40 degrees.  Its rings are tilted
towards us by just under 5 degrees so you will need good seeing conditions
to pick out Cassini's division.


KEPLER DISCOVERS FIVE NEW EXOPLANETS
Science Daily

The Kepler space telescope, intended to find Earth-size planets in the
`habitable zones' of Sun-like stars, was launched in 2009 March.  It
continuously and simultaneously observes more than 150,000 stars, and has
already measured hundreds of possible planet signatures that are being
analyzed.  Kepler looks for the signatures of planets by measuring dips in
the brightness of stars.  When planets cross in front of, or transit, their
stars, they periodically block part of the starlight.  The size of the
planet can be derived from the size of the dip, and the temperature can be
estimated from the characteristics of the star it orbits and the planet's
orbital period.

Now Kepler has discovered its first five new exo-planets, which have been
named Kepler 4b, 5b, 6b, 7b and 8b.  [That begs the question why the numbers
did not start at 1!]  The five planets are all much larger than the Earth.
Known as 'hot Jupiters', they range in size from similar to Neptune to
larger than Jupiter.  They have orbital periods ranging from 3.3 to 4.9
days.  Estimated temperatures range from 1200 to 1600 degrees C.  NOT very
Earth-like!  As the mission proceeds and Kepler has time to gather more
data, smaller and cooler planets should be found.  While many of the
signatures detected so far are likely to be caused by things other than
planets, such as small stars orbiting larger stars, ground-based
observatories have confirmed the existence of the five exo-planets.  Kepler
is expected to continue operations until at least 2012 November.


INTERGALACTIC GAS STREAM LONGER THAN THOUGHT NRAO

A stream of gas flowing from the Magellanic Clouds around our own Milky Way
is much longer and older than previously thought.  The Magellanic Clouds are
the Milky Way's two nearest neighbour galaxies, about 150,000 to 200,000
light-years away, and are deep in the Southern Hemisphere; they are much
smaller than our Galaxy and may have been distorted by its gravity.

The first evidence of the gas stream, named the Magellanic Stream, was
discovered more than 30 years ago, and subsequent observations added
tantalizing suggestions that there was more.  However, until now it was not
clear that all the gas was part of the same system.  Now, astronomers have
used the Green Bank radio telescope to fill important gaps in the picture of
gas streaming outward from the Magellanic Clouds.  They combined their data
with those from earlier studies with other radio telescopes, including those
at Arecibo in Puerto Rico, Parkes in Australia, and Westerbork in the
Netherlands.  The result shows that the stream is more than 40% longer than
was previously known with certainty.

One consequence of the added length of the gas stream is that it must be
older.  Its age is now estimated at 2.5 billion years.  The revised size and
age of the Magellanic Stream also provides a new possible explanation for
how the flow got started.  The new age of the stream puts its beginning near
a time when the two Magellanic Clouds may have passed close to each other,
triggering massive bursts of star- formation.  The strong stellar winds and
supernova explosions from that burst of star-formation might have blown out
the gas and started it flowing toward the Milky Way.  Earlier hypotheses for
the stream's cause required the Magellanic Clouds to pass much closer to the
Milky Way, but recent orbital simulations have cast doubt on such
mechanisms.


LESS ORDINARY MATTER THAN OTHERS SUPPOSED University of Maryland

An international team of scientists has found that individual galactic
objects have less ordinary matter, relative to dark matter, than does the
Universe as a whole.  Some scientists believe all ordinary matter, the
protons and neutrons that make up people, planets, stars, and all that we
can see, is a mere fraction (some say 17%) of the total matter in the
Universe.  The protons & neutrons of ordinary matter are referred to as
baryons by devotees of particle physics and cosmology.
The remaining 83% is attributed to mysterious 'dark matter', the existence
of which is inferred largely from its gravitational pull on visible matter.
Dark matter is presumed to be some new form of non-baryonic particle -- the
stuff scientists hope the Large Hadron Collider at CERN will create in
high-energy collisions between protons.  The team posed the question of
whether the 'universal' ratio of baryonic matter to dark matter holds on the
scales of individual structures like galaxies.  One might expect galaxies
and clusters of galaxies to be made of the same stuff as the Universe as a
whole, so if you were naive enough you might think that if you made an
accounting of the normal matter in each object, and its total mass, you
ought to get the same 17%.

However, the team suggests that individual objects have less ordinary
matter, relative to dark matter, than they would expect from the cosmic mix,
sometimes a lot less.  Just how much less depends systematically on scale,
according to the researchers.  The smaller an object, the further its ratio
of ordinary matter to dark matter is from the cosmic mix.  The research
indicates that the largest bound structures, rich clusters of galaxies, have
14% of ordinary baryonic matter, close to the 17% they expect.  In smaller
objects -- individual galaxies and satellite galaxies -- the normal matter
content gets steadily less.  In the smallest dwarf satellite galaxies, the
content of normal matter is only about 1% of what they think it should be.
The variation of the baryon content is very systematic with scale, so they
say.  The smaller the galaxy, the smaller is its ratio of normal matter to
dark matter.  To put it another way, the smallest galaxies are very
dark-matter-dominated.


ASTRONOMERS TRY TO EXPLAIN HUBBLE SEQUENCE RAS

Not for the first time, some astronomers have been trying to explain the
diversity of galaxy shapes.  They tracked the evolution of galaxies over the
thirteen billion years from the early Universe to the present day.  Galaxies
make up most of the visible component of the cosmos.  The smallest have a
few million and the largest as many as a million million stars.  American
astronomer Edwin Hubble developed in the 1930s a taxonomy for galaxies that
has since become known as the 'Hubble Sequence'.  There are three basic
shapes: spiral, where arms of material wind out in a disc from a small
central bulge, barred spirals, where the arms wind out in a disc from a
larger bar of material, and elliptical, where the galaxy's stars are
distributed more evenly in a bulge without arms or disc.  For comparison,
the galaxy we live in has between two and four hundred thousand million
stars and is classified as a barred spiral.

Explaining the Hubble Sequence is complex.  The different types clearly
result from different evolutionary paths but at least until now a detailed
explanation has eluded scientists.  The team combined data from the infrared
Two-Micron All-Sky Survey (2MASS) with their computer model to reproduce the
evolutionary history of the Universe.
To their surprise, their computations reproduced not only the different
galaxy shapes but also their relative numbers.  The astronomers' model is
underpinned by and endorses the 'Lambda Cold Dark Matter' model of the
Universe.  Here 'Lambda' is the highly mysterious 'dark energy' component
that some astronomers now like to believe makes up about 72% of the cosmos,
with cold dark matter making up another 23%.  [It's not our fault if even
the assertions, let alone the numbers, in different items in these Bulletins
don't chime with one another!]  Galaxies are thought to be embedded in very
large haloes of dark matter, and researchers believe that those may be
crucial to their evolution.  Their model suggests that the number of mergers
between the haloes and their galaxies drives the final outcome
-- elliptical galaxies result from multiple mergers whereas disc galaxies
have seen none at all.  Our Milky Way galaxy's barred-spiral shape suggests
that it has had a complex history, with only a few minor collisions and at
least one episode where the inner disc collapsed to form the large central
bar.  The goal now is to compare the model predictions with observations of
more distant galaxies.


HST OBSERVES VERY DISTANT GALAXIES
STSI

The Hubble space telescope has observed galaxies even more distant than
before and uncovered a primordial population of compact and ultra-blue
galaxies that have never been seen before.  The data come from images taken
on the 'Ultra-deep Field' last August with the new 'Wide-Field Camera 3',
which are deep enough at near-infrared wavelengths to show galaxies at
redshifts from z=7 to beyond z=8.
The clear detection of galaxies between z=7 and z=8.5 corresponds to
look-back times of approximately 12.9 to 13.1 billion years ago.  The images
have been discussed by astronomers who say that the faintest galaxies show
signs of linkage to their origins from the first stars.
They are so blue that they must be extremely deficient in heavy elements,
thus representing a population that has nearly primordial characteristics.

The existence of such galaxies pushes back the time when galaxies began to
form to before 500-600 million years after the Big Bang.
The deep observations also demonstrate the progressive build-up of galaxies
and provide further support for the hierarchical model of galaxy assembly
whereby small objects accrete mass, or merge, to form bigger objects by a
process of collision and agglomeration.  The galaxies are as small as 1/20th
the Milky Way's diameter and are crucial to understanding the evolutionary
link between the birth of the first stars and the formation of the first
galaxies.  Astronomers also combined the new Hubble data with observations
from the Spitzer space telescope to estimate the ages and masses of the
primordial galaxies.  Their masses seem to be only 1% of that of the Milky
Way and show that the galaxies, seen at 700 million years after the Big
Bang, must have started forming stars hundreds of millions of years earlier,
pushing back the time of the earliest star-formation in the Universe.



Bulletin compiled by Clive Down

(c) 2010 the Society for Popular Astronomy




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