SPA ENB No. 294

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                 The SOCIETY for POPULAR ASTRONOMY
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         Electronic News Bulletin No. 294    2010 August 29
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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 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://www.popastro.com/



PERSEIDS 2010
By Alastair McBeath, SPA Meteor Section Director

Data from the Perseid meteor shower has continued to pour in since
the very early report in ENB 293, both to the SPA and the
International Meteor Organization (IMO). Even those observers
who were clouded-out near the maximum, but who were able to
observe at other times instead, seemed to have enjoyed whatever
view of the Perseids they managed. Results are still preliminary at
this stage. However the IMO's "live" Perseids webpage, giving an
overview of what meteor watchers across the world recorded
(at http://www.imo.net/live/perseids2010/ ), has indicated Zenithal
Hourly Rates (ZHRs) were roughly 60 to 100 from about 16h UT
on August 12 through to ~21h UT on the 13th. Several potentially
stronger phases were apparent within this lengthy spell, though it is
uncertain how significant these may have been as yet. One
particularly interesting period was near 17h-18h UT on August 12,
when ZHRs seemed to have peaked briefly at ~130 +/- 10. Part
of this interval was only a little after the predicted possible encounter
with Comet 109P/Swift-Tuttle's 1479 AD dust trail, parent comet
to the Perseid shower, around 16:50 UT that day. It was believed
the Earth might only skim the outer part of this trail however, and it
is not clear what role, if any, the expectations of the observers may
have had on the claimed activity. For example, early European
radio meteor results reaching the SPA showed no good indication
that anything unusual had occurred at this time. The Perseid radiant
however, while circumpolar for many mid-northern hemisphere
locations, was at about its lowest for the day from Europe then, so
this is not conclusive.

Just over 2800 Perseids have been reported to the Meteor Section
during August now, most from the ten-day spell beginning on August
7-8. Regrettably, many observers struggled with unhelpful sky-
conditions on the critical August 12-13, in Britain and elsewhere in
the world, so a better picture has emerged of how ZHRs behaved
rising before and falling after the maximum than on that night itself.
Despite this, ZHRs (compiled from skies where the limiting
magnitude - LM - was +5.5 or better, cloud cover was less than
20%, and where the radiant was above 25° elevation) from 21h-
08h UT on August 12-13 averaged ~70-110 in the SPA analysis.
Weather problems also reduced the number of meteors available
for the magnitude analysis, albeit the quantity of meteors still allowed
a useful degree of validity to the results. Mean magnitudes,
corrected to an LM +6.5 sky, were +2.4 for the Perseids (776
meteors) and +3.4 for the sporadics (252), both values quite typical.
Too few trained meteor details were provided to allow an analysis of
them this time, though colloquial comments indicated a good
percentage of Perseids left persistent trains, largely as expected.

Also as usual, numerous fireballs (meteors of magnitude -3 or
brighter), mostly Perseids, were reported across the shower's
maximum, but one on August 12-13 at 21:43 +/- 1 minute UT
seemed to have been especially impressive, perhaps peaking
between magnitudes -8 to -12. It was spotted from probably four
locations in central-southern England, two of which sightings were
mentioned on the SPA's Observing Forum "Perseids 2010" topic
(beginning at http://snipurl.com/10nill  ), those made by "@@"
(posting timed at 22:13 BST on August 12 - note the automatic
time-stamps appeared to be inaccurate compared to actual clock
time) and "UtopiaPlanitia" (22:51 BST also on the 12th). The
details currently available cannot confirm all definitely saw the same
meteor, but assuming they did would suggest the meteor likely flew
high above the north-Northamptonshire/Cambridgeshire area, or
points adjacent. Another spectacular object was spotted at 00:32
UT on August 12-13 by Karl Antier in Provence, southern France,
despite clouds so thick he could barely see Jupiter at times. Luckily,
one of his colleagues some distance away had better conditions at
the essential moment, and by-chance, managed to image this event.
See: http://snipurl.com/10uabf  .

Back in the UK, looking at the distribution of the more fortunate
SPA observers showed southern Britain, approximately bounded to
the north by a line from south Wales through the West Midlands to
the Wash, enjoyed the better conditions on August 10-11, 11-12
and 12-13, though a few spots in Northern Ireland, central-southern
Scotland and near Dundee on the east Scottish coast, enjoyed
some breaks at times on August 12-13 too. Elsewhere, the clearer
skies favoured nights further from the peak. Several observers took
advantage of the holidays to venture to darker-sky sites, with those
travelling to East Anglia and southwest England enjoying the greatest
success, including contributors to the Perseid topics on the SPA's
and UK Weather World's Space Weather Forums (the latter
beginning at http://snipurl.com/10nime ). Similarly, colleagues in
North America and France found taking to the road beneficial in the
hunt for clearer weather. Perhaps the most intrepid was the group
with Richard Kramer, who, over two days, drove and walked to
the summit of Saddleback Mountain (1255 metres/4116 feet) near
the Rangely Lakes region of western Maine in the NE USA for the
shower's maximum night - and better still, they enjoyed some
clearer weather for a time when they got there! His report of their
adventure, with those of lots more, can be read on the Meteorobs
website, http://www.meteorobs.org .

The list of observers to report to us so far was as follows, comprising
quite casual viewers, through to dedicated meteors watchers.
Unmarked contributors, or those with "+ V", provided visual results,
"R" means radio data were presented, and "I" imaging observations.
Many details were taken from the two Forum topics mentioned
above, and more were kindly provided by its leader Mark Davis
from the North American Meteor Network (NAMN; see
http://www.namnmeteors.org). To everyone below, very many
thanks and a hearty "Well Done" for your efforts!

Michael Adams (England), Salvador Aguirre (Nevada, USA;
NAMN), "akkan" (England), Sandy Allan (Scotland), Chris Alder
(England), "andyT" (Wales), Karl Antier (France), "@@" (England),
Tom Banks (England), "billden" (England), Nigel Bolton (England),
Michael Boschat (Nova Scotia, Canada; NAMN; I, R + V), Pat
Branch (Texas, USA; NAMN), "Bushy" (England), Michael Catlin
(North Yorkshire; NAMN), "Charles" (England), "ChaserUK"
(Channel Islands), "Cliff" (England; I + V), "coldfieldboundary"
(Belgium), Tibor Csorgei (Slovakia; NAMN), Amanda Davies &
husband (Wales), Mark Davis & daughter (South Carolina, USA;
NAMN), Paul Domaille (Channel Islands), David Entwistle
(England; R), Lorraine Evans (England), Mike Feist (England),
George Gliba (West Virginia, USA; NAMN), Bill Godley
(Oklahoma, USA; NAMN), "Godot" (England; I + V), Shelagh
Godwin (England), Bill Haddon (California, USA), Dave Hancox
(Scotland; I + V), Alan Heath (England; R), "HippyChippy"
(England), Ken Hodonsky (Nebraska, USA; NAMN), "Jamie
d" & fiancée (England), "Jane B" (England; I + V), "JohnF"
(England), Sam Jowett (England), Richard Kramer & colleagues
(Maine, USA; NAMN), "Lawrie" (location unstated),
"Lightningfox92" (England), "louise79" (Northern Ireland), Tony
Markham (England), Pierre Martin (Ontario, Canada; NAMN),
Paul Martsching (Iowa, USA; NAMN), Kenneth Meadows
(England), Peter Meadows (England; I), "Miguella" (England), Jane
Mills (England), Koen Miskotte (France; NAMN), "Naplesnut"
(England), David Oesper (Texas, USA; NAMN), Don Olson &
colleagues (Texas, USA), Kenneth Pamment (England), "pettinger"
(England), Robin Scagell (England; I + V), "Scoggy" (England),
Pete Scott (England; I + V), "scrapemedic" (England), Jason Smith
(England), "snow hope" (Northern Ireland), Chris Stephen (Florida,
USA; NAMN), R Stevenson (England), Rich Taibi (Maryland &
West Virginia, USA; NAMN), "tcmorris78" (Scotland), István
Tepliczky (Hungary; NAMN), Harold Tinker (Ohio, USA), Peter
Upton (England), "UtopiaPlanitia" (England), "Vadno581" &
daughters (Scotland), "vincentnm" (location unstated; I), Colin
Watling (England), William Watson (Ontario, Canada, New York
& Pennsylvania, USA; NAMN), "Winso" (England), "WSM-
Weather" (England), and the Director (England).

All further observations would be most welcome!


ADDITIONAL AUGUST FIREBALLS
By Alastair McBeath, SPA Meteor Section Director

Apart from those fireballs noted already, and as discussed last time,
two more from the first half of August have been recorded now from
more than one location. August 4-5, around 22:00 UT brought a
very bright, long-pathed, slow-moving fireball for lucky witnesses at
sites in Hampshire and the West Midlands. Then on August 10-11,
within about eight minutes of 22:07 UT, a magnitude -4/-7 possible
Alpha Capricornid fireball was seen from four locations in London,
Berkshire, Buckinghamshire and Wrexham. Little other information
has been deduced for either object as yet, unfortunately.

Fireball observations made from places in the British Isles or nearby
are always welcomed by the Meteor Section. For advice on what
details to submit (including an e-mail report form), see the "Making
and Reporting Fireball Observations" page of the SPA website, at:
http://snipurl.com/u8aer  .


PLANETS
By Andrew Robertson, SPA Planetary Section Director

As Jupiter is coming to prominence (reaches opposition on September
21) I'm now starting to get more observational reports from members.
A selection of them can be viewed at    http://snipurl.com/xc9r8   .

The SEB is still faded but the GRS is very red.  Oval BA is near the
GRS, as can be seen in the excellent image taken by SPA member Simon
Kidd:  http://snipurl.com/10tbua  .  I had a good view of it in the
early hours of August 24.  But you don't need expensive or exotic
equipment to enjoy observing the planets -- look at this sketch made
by Cliff Meredith using a 60-mm spotting 'scope that he bought from
Aldi's:   http://snipurl.com/10tckw   .

There is a conjunction of Jupiter and Uranus during September,
providing an opportunity to observe both planets in the same field of
view.  Between 12th and 26th they are a degree or less apart, closest
approach being on September 18/19 when Uranus is just 50' north of
Jupiter.  At the moment Uranus, which like Jupiter comes to opposition
on September 21, lies 2 degrees to the west of Jupiter and is moving
slowly westwards, but not as quickly as Jupiter.  Of course all the
outer planets exhibit retrograde motion near opposition as the Earth
'overtakes' them, but the nearer ones show faster angular motion than
the more distant ones, so Jupiter will 'overtake' Uranus while both
are in the phase of retrograde motion.  In fact they are both
reversing across the equinoctial colure about now -- Uranus crossed it
on August 25 and Jupiter will do so on September 14.

Neptune came to opposition on August 20.  About that date it moved
back from Aquarius into Capricornus; it is not favourably placed for
observation from the British Isles, having been south of the equator
for almost as long as anyone can remember, but younger members need
not despair, as it is gradually moving north now and will reach the
equator in about 15 years' time and Gemini in about 55 years!

There is a favourable morning apparition of Mercury from mid-
September, Greatest Elongation West (18 degrees) being on the 19th.

Any reports of observations would be most welcome via:
http://popastro.com/planet/contact/




TROJAN ASTEROID FOUND NEAR NEPTUNE
Subaru Telescope facility, Hawaii

Astronomers using the 8.2-m Subaru Telescope in Hawaii have discovered
the first Neptune Trojan asteroid, 2008 LC18, to be found near
Neptune's L5 Lagrangian point L5.  Lagrangian points are five places
in space where the gravitational forces from two bodies of very
unequal mass, such as the Sun and a planet, are in balance such that
small bodies like asteroids can remain more or less fixed with respect
to the planet.  The Lagrangian points L1, L2, and L3, which are
points along the direct line drawn through the two main bodies, are
unstable, so a slight displacement of an object there may result in
its permanent departure.  The other points, L4 and L5, 60° ahead of
and behind the planet, are stable, so dust grains and other objects
remain in the vicinity and tend to collect there.  Trojans share their
planet's orbit, but they do not collide with the planet because they
stay safely near the Lagrangian point ahead of or behind it.  Neptune
was already known to be accompanied by six Trojan asteroids, but they
are all near the L4 point.  It is more difficult to discover them near
L5, because that point is currently in Sagittarius, in a very rich
Milky-Way star field nearly in the line of sight to the Galactic
Centre.  It is estimated that the 'new' Neptune Trojan has a diameter
of about 100 km.


RICHEST PLANETARY SYSTEM DISCOVERED
ESO

Astronomers have discovered a planetary system containing at least
five planets.  They used the HARPS spectrograph, attached to ESO's
3.6-m telescope at La Silla, Chile, for a six-year study of the
Sun-like star HD 10180, located about 40 parsecs away in the southern
constellation Hydrus.  From the 190 individual HARPS measurements, the
astronomers detected the tiny back and forth motions of the star
caused by the complex gravitational attractions from five or more
planets. The five strongest signals correspond to planets with
Neptune-like masses -- between 13 and 25 Earth masses -- which orbit
the star with periods ranging from about 6 to 600 days. They are
between 0.06 and 1.4 AU (Astronomical Units or Earth--Sun distances)
from their central star.  There may be other planets present in the
system, but the evidence is inconclusive.

The newly discovered system of planets around HD 10180 differs from
the Solar System inasmuch as it has five Neptune-like planets all
lying within a distance equivalent to the orbit of Mars, but no
Jupiter-like giant.  All the planets seem to have almost circular
orbits.  So far, astronomers know of fifteen systems with at least
three planets.  Using the new discovery as well as data for other
planetary systems, the astronomers found an equivalent of the
Titius-Bode law that exists in our Solar System: the distances of the
planets from their star seem to follow a regular pattern.  Another
result found by astronomers studying such systems is that massive
planetary systems are found around relatively massive and metal-rich
stars, while the four lowest-mass systems belong to lower-mass and
metal-poor stars.  Theoreticians have tried to develop models that
mimic that property.


'CITIZEN SCIENTISTS' DISCOVER NEW PULSAR
University of Wisconsin

Einstein@Home, based at the University of Wisconsin at Milwaukee and
at the Max-Planck-Institute in Germany, is a project that enlists the
aid of 250,000 volunteers from 192 countries, who donate time from
their home and office computers to search for signals from radio
pulsars in observations from Arecibo, the world's largest and most
sensitive radio telescope.  More than a year after the project
started, the first deep-space discovery has been made by it, when
three lay people -- a German and an American couple -- have discovered
a new radio pulsar.  The object, PSR J2007+2722, is a neutron star
that rotates 41 times per second.  It is in the Milky Way, about 5000
parsecs away in the constellation Vulpecula.  Unlike many pulsars that
spin as quickly and steadily, PSR J2007+2722 sits alone in space, and
has no orbiting companion star.  Astronomers think it may be a
'recycled' pulsar that has lost its companion, but they can't rule
out that it may be a young pulsar born with a lower-than-usual
magnetic field.


GAMMA-RAY NOVA DISCOVERED
Space.com

A nova is a thermonuclear explosion on the surface of a white-dwarf
star.  It is fuelled by hydrogen transferred from a companion star.
Novae emit X-rays, but until now they have not been known to emit
gamma-rays, a still more energetic form of radiation.  Now researchers
using the orbiting Fermi telescope have discovered gamma-rays from a
nova called V407 Cygni, some 2700 parsecs away.  It is a binary system
which consists of a white dwarf and a pulsating red giant.  The
gamma-rays came after a nova explosion in the system, spotted by
Japanese amateur astronomers in March, which at its peak was just
below the level of naked-eye visibility, brighter than at any other
time in the 70-odd years that the system has been under observation.
The researchers suggest that the gamma-rays were generated when the
blast waves from the nova collided with the dense wind from the red
giant.

In most novae, the white dwarf's companion is a normal main-sequence
star, whose stellar wind is light compared with that of the red giant
in V407 Cygni, so there is far less material with which to generate
gamma-rays.  Very few binary systems combine the kind of white-dwarf
stars that give rise to novae with red giant companions, so gamma-ray
novae are probably quite rare.


ACTIVE STAR FORMATION IN DISTANT CLUSTER OF GALAXIES
Texas A&M University

Images obtained with the Spitzer space telescope of an early, distant,
cluster of galaxies have revealed that a significant fraction of those
ancient galaxies were still actively forming stars.  The images looked
back in time nearly 10 billion years at a high-redshift cluster known
as CLG J02182-05102.  The cluster is 'modern' in its appearance and
size despite being observed 'only' 4 billion years after the Big Bang,
and is seen to be producing hundreds to thousands of new stars every
year, a higher birth-rate than that in present 'nearby' galaxies.

What is particularly striking is the fact that the stellar birth rate
is higher in the cluster's centre than at its edges, the exact
opposite of what happens in our part of the Universe where the cores
of galaxy clusters are known to be galactic graveyards full of massive
elliptical galaxies composed of old stars.  A well-established
hallmark of galaxy evolution in action is how the fraction of
star-forming galaxies decreases with increasing galaxy density.  In
other words, there are more star-forming galaxies in the field than in
the crowded cores of galaxy clusters.  However, in the old cluster
there are many galaxies with star-formation rates comparable with
those of their cousins in the lower-density field environment.




Owing to holidays the next scheduled edition of the bulletin will be
issued on 26 September 2010.



Bulletin compiled by Clive Down


(c) 2010 the Society for Popular Astronomy


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Good Clear Skies
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Astrocomet
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Colin James Watling
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Profile: http://www.google.com/profiles/astrocomera
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Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
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Web: http://lyra.freewebsites.com/
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Information: http://www.clubbz.com/club/2895/LOWESTOFT---3054/Lowestoft%20And%20Great%20Yarmouth%20Regional%20Astronomers%20(Lyra