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Monday, 20 January 2014

SPA ENB No. 368

          Electronic News Bulletin No. 368   2014 January 19

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

Harvard-Smithsonian Center for Astrophysics
Astronomers have discovered the first Earth-mass planet that transits,
or crosses in front of, its host star.  KOI-314c is the lightest
planet to have both its mass and physical size measured. Surprisingly,
although the planet weighs the same as Earth, it is 60 percent larger
in diameter, meaning that it must have a very thick, gaseous
atmosphere.  The planet might have the same mass as Earth, but it is
certainly not Earth-like and proves that there is no clear dividing
line between rocky worlds like Earth and fluffier planets like water
worlds or gas giants.   The team gleaned the planet's characteristics
using data from NASA's Kepler spacecraft.  KOI-314c orbits a dim, red
dwarf star located approximately 200 light-years away.  It circles its
star every 23 days.  The team estimates its temperature to be 105
degrees Centigrade.  KOI-314c is only 30 percent denser than water
which suggests that the planet is enveloped by a significant
atmosphere of hydrogen and helium hundreds of miles thick.  It might
have begun life as a mini-Neptune and lost some of its atmospheric
gases over time, boiled off by the intense radiation of its star.
Weighing such a small planet was a challenge.  Conventionally,
astronomers measure the mass of an exoplanet by measuring the tiny
wobbles of the parent star induced by the planet's gravity.  This
radial velocity method is extremely difficult for a planet with
Earth's mass.  The previous record holder for a planet with a measured
mass (Kepler-78b) weighed 70 percent more than Earth.  To weigh
KOI-314c, the team relied on a different technique known as transit
timing variations (TTV).  This method can only be used when more than
one planet orbits a star. The two planets tug on each other, slightly
changing the times that they transit their star.  Rather than looking
for a wobbling star, astronomers essentially look for a wobbling
planet, Kepler saw two planets transiting in front of the same star
over and over again.  By measuring the times at which these transits
occurred very carefully, they were able to discover that the two
planets are locked in an intricate dance of tiny wobbles giving away
their masses.  The second planet in the system, KOI-314b, is about the
same size as KOI-314c but significantly denser, weighing about 4 times
as much as Earth.  It orbits the star every 13 days, meaning it is in
a 5-to-3 resonance with the outer planet.  TTV is a very young method
of finding and studying exoplanets, first used successfully in 2010.
The planet was discovered by chance by the team as they scoured the
Kepler data not for exoplanets, but for exomoons.  The Hunt for
Exomoons with Kepler (HEK) project scans through Kepler's planet haul
looking for TTV, which can also be a signature of an exomoon.  When
astronomers noticed this planet showed transit timing variations, the
signature was clearly because of the other planet in the system and
not a moon.  At first they were disappointed it wasn't a moon but then
they soon realized it was an extraordinary measurement.

University of Toronto
An object located near and likely orbiting a very young star about 440
light years away from the Sun, is leading astrophysicists to believe
that there is not an easy-to-define line between what is and is not a
planet.  Astronomers have very detailed measurements of the object
spanning seven years, even a spectrum revealing its gravity,
temperature, and molecular composition.  Still they can't yet
determine whether it is a planet or a failed star -- what we call a
'brown dwarf'.  Depending on what measurement you consider, the answer
could be either.  Named ROXs 42Bb for it's proximity to the star
ROXs 42B, the object is approximately nine times the mass of Jupiter,
below the limit most astronomers use to separate planets from brown
dwarfs, which are more massive.  However, it is located 30 times
further away from the star than Jupiter is from the Sun.  Most
astronomers believe that gas giant planets like Jupiter and Saturn
formed by core accretion, whereby the planets form from a solid core
that then accretes a massive gaseous envelope.  Core accretion
operates most efficiently closer to the parent star owing to the
length of time required to first form the core.  An alternate theory
proposed for forming gas giant planets is disk instability -- a
process by which a fragment of a disk gas surrounding a young star
directly collapses under its own gravity into a planet.  This
mechanism works best farther away from the parent star.
Of the dozen or so other young objects with masses of planets observed
by the team, some have planet-to-star mass ratios less than about 10
times that Jupiter and are located within about 15 times Jupiter's
separation from the Sun.  Others have much higher mass ratios and/or
are located more than 50 times Jupiter's orbital separation,
properties that are similar to much more massive objects widely
accepted to not be planets.  The first group would be planets formed
by core accretion, and the second group probably formed just like
stars and brown dwarfs. In between these two populations is a big gap
separating true planets from other objects.  Astronomers say that the
new object starts to blur this distinction between planets and brown
dwarfs, and may lie within and begin to fill the gap.  It's very hard
to understand how this object formed like Jupiter did.  However, it's
also too low mass to be a typical brown dwarf; disk instability might
just work at its distance from the star.  It may represent a new class
of planets or it may just be a very rare, very low-mass brown dwarf
formed like other stars and brown dwarfs: a 'planet mass' brown dwarf.
Regardless, it should spur new research in planet and star formation
theories, and serve as a crucial reference point with which to
understand the properties of young planets at similar temperatures,
masses and ages.

BBC News
Astronomers have discovered a triple star system which could reveal
the true nature of gravity.  They found a pulsar with two white dwarfs
all packed in a space smaller than Earth's orbit of the Sun. The
trio's unusually close orbits allow precise measurements of gravity
and could resolve difficulties with Einstein's theories.  This triple
system gives us a natural cosmic laboratory far better than anything
found before for learning exactly how such three-body systems work and
potentially for detecting problems with general relativity that
physicists expect to see under extreme conditions.  Pulsars emit
lighthouse-like beams of radio waves that rapidly sweep through space
as the stars spin on their axes and are formed after a supernova
collapses a burnt-out star to a dense, highly magnetised ball of
Using the Green Bank Telescope, the astronomers discovered a pulsar
4,200 light-years from Earth, spinning nearly 366 times per second.
Such rapidly-spinning bodies are called millisecond pulsars - and are
used by astronomers as precision tools for studying gravitational
effects and other phenomena.  Subsequent observations showed the
pulsar is in a close orbit with a white dwarf star, and that pair is
in orbit with another, more-distant white dwarf.  Three-body systems
are keenly studied because they allow competing theories of gravity to
be tested. But until now the only known triple system containing a
millisecond pulsar was one with a planet as the outer companion,
causing only weak gravitational interactions.  The gravitational
perturbations imposed on each member of this system by the others are
incredibly pure and strong.  By precisely timing the arrival of the
pulses, the scientists were able to calculate the geometry of the
system and the masses of the stars.  The pulsar's inner white-dwarf
companion has an orbital period of less than two days, while the outer
dwarf has a period of almost a year.  The system gives the scientists
the best opportunity yet to look for violations of the equivalence
principle described by Einstein - which states that the effect of
gravity on a body does not depend on the nature or internal structure
of that body.   This was famously illustrated by Galileo's dropping of
two balls of different weights from the Leaning Tower of Pisa, and
Apollo 15 Commander Dave Scott's dropping of a hammer and a falcon
feather while standing on the Moon in 1971.  Rather than drifting to
the ground, the feather plummeted, falling as fast as the hammer.
Without air resistance to slow the feather, both objects hit the lunar
dust at the same time.  While Einstein's theory of general relativity
has so far been confirmed by every experiment, it is not compatible
with quantum theory.  Because of that, physicists expect that it will
break down under extreme conditions.  High-precision timing of the
pulsar's "lighthouse" flashes will let astronomers hunt for deviations
in the equivalence principle at a sensitivity several orders of
magnitude greater than ever before.  Finding a deviation would
indicate a breakdown of general relativity and point us toward a new,
correct theory of gravity.

Galaxies can be remarkably dusty places and supernovae are thought to
be a primary source of that dust, especially in the early Universe.
But direct evidence of a supernova's dust making capabilities has been
slim up to now, and could not account for the copious amount of dust
detected in young, distant galaxies.  But now observations with ALMA
are changing that.   An international team of astronomers used ALMA to
observe the glowing remains of Supernova 1987A , which is in the Large
Magellanic Cloud, a dwarf galaxy orbiting the Milky Way about 160 000
light years from Earth.  SN 1987A is the closest observed supernova
explosion since Johannes Kepler's observation of a supernova inside
the Milky Way in 1604.   Astronomers predicted that as the gas cooled
after the explosion, large amounts of dust would form as atoms of
oxygen, carbon, and silicon bonded together in the cold central
regions of the remnant.  However, earlier observations of SN 1987A
with infrared telescopes, made during the first 500 days after the
explosion, detected only a small amount of hot dust.  Using ALMA, the
research team was able to image the far more abundant cold dust, which
glows brightly in millimetre and submillimetre light.  The astronomers
estimate that the remnant now contains about 25 percent the mass of
the Sun in newly formed dust.  They also found that significant
amounts of carbon monoxide and silicon monoxide have formed. 
Supernovae, however, can both create and destroy dust grains.  As the
shockwave from the initial explosion radiated out into space, it
produced bright glowing rings of material, as seen in earlier
observations with the NASA/ESA Hubble Space Telescope.  After hitting
this envelope of gas, which was sloughed off by the progenitor red
giant star as it neared the end of its life, a portion of this
powerful explosion rebounded back towards the centre of the remnant.
At some point, this rebound shockwave will slam into these billowing
clumps of freshly minted dust and it's likely that some fraction of
the dust will be blasted apart at that point.  It's hard to predict
exactly how much — maybe only a little, possibly a half or two thirds.
If a good fraction survives and makes it into interstellar space, it
could account for the copious dust astronomers detect in the early

BBC News
NASA has won White House backing to extend the life of the
International Space Station for a further four years, until 2024.
Construction of the ISS began in 1998 and is a joint venture between
the US, Russia, Canada, Japan, and states in the European Space Agency
(ESA).  For the extension to happen, it will likely need the partners'
support.  Their current commitments run to 2020, but many engineers
believe the station could work safely until at least 2028.  NASA says
that it is feasible to continue operating the ISS if some partners
decided not to stay on board, but it expects them all to offer full
support, even if the agreements took a few years to put in place.
Certainly, Germany, Europe's biggest contributor to the ISS project is
keen to see the $100bn orbiting platform operate for many years into
the future.
At the moment, the station is solely reliant on Russian Soyuz capsules
to rotate the platform's six-person crew.   NASA is therefore seeding
American companies, including Sierra Nevada, to help them design and
build alternatives.  The mini-shuttle is known as the Dream Chaser and
would launch atop an Atlas rocket from Cape Canaveral in Florida.  It
is envisaged that the vehicle will make its maiden voyage into orbit
in 2016, in an autonomous configuration; and then fly its first manned
mission in 2017.  The Ariane 5 was originally conceived as a human
launcher, and Europe spent considerable funds designing its own mini-
shuttle called Hermes to go on top of the rocket.  Budget constraints
eventually led to the Hermes project being cancelled.
NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE)
spacecraft has discovered a never-before-seen asteroid -- its first
such discovery since coming out of hibernation last year. NEOWISE
originally was called the Wide-field Infrared Survey Explorer (WISE),
which had made the most comprehensive survey to date of asteroids and
comets.  The spacecraft was shut down in 2011 after its primary
mission was completed, but in September 2013, it was reactivated,
renamed and given a new mission, which is to assist NASA's efforts to
identify the population of potentially hazardous near-Earth objects
(NEOs).  NEOWISE also can assist in characterizing previously detected
asteroids that could be considered potential targets for future
exploration missions.  NEOWISE's first discovery of its renewed
mission came on Dec. 29 -- a near-Earth asteroid designated 2013 YP139.
The mission's sophisticated software picked out the moving object
against a background of stationary stars.  As NEOWISE circled Earth
scanning the sky, it observed the asteroid several times over half a
day before the object moved beyond its view.  2013 YP139 is about 43
million kilometres from Earth. Based on its infrared brightness,
scientists estimate it to be roughly 650 metres in diameter and
extremely dark, like a piece of coal.  The asteroid circles the Sun
in an elliptical orbit tilted to the plane of our solar system and is
classified as potentially hazardous. It is possible for its orbit to
bring it as close as 300,000 miles from Earth, a little more than the
distance to the Moon.  However, it will not come that close within
the next century.  WISE discovered more than 34,000 asteroids and
characterized 158,000 throughout the solar system during its prime
mission in 2010 and early 2011.  Its reactivation in September
followed 31 months in hibernation.  NEOWISE will continue to detect
asteroids and comets.

One of the fastest spacecraft ever built -- NASA's New Horizons -- is
hurtling through the void at nearly one million miles per day. 
Launched in 2006, it has been in flight longer than some missions
last, and it is nearing its destination: Pluto.  Closest approach is
scheduled for July 2015 when New Horizons flies only 10,000 km from
Pluto, but the spacecraft will be busy long before that date.  The
first step, in January 2015, is an intensive campaign of photography
by the Long Range Reconnaissance Imager or "LORRI."  This will help
mission controllers pinpoint Pluto's location, which is uncertain by
a few thousand kilometres.  LORRI will photograph the planet against
known background star fields.  The images will be used to refine
Pluto's distance from the spacecraft, and then fire the engines to
make any necessary corrections.  At first, Pluto and its large moon
Charon will be little more than distant pinpricks--but soon they will
swell into full-fledged worlds.  By late April 2015, the approaching
spacecraft will be taking pictures of Pluto that surpass the best
images from Hubble.   By closest approach in July 2015, a whole new
world will open up to the spacecraft's cameras.  If New Horizons flew
over Earth at the same altitude, it could see individual buildings
and their shapes.

By Geoff Elston, SPA Solar Section Director 

I've been trying out a combination of a new full aperture solar filter
(a "Sonnenfilter SF100" which I bought at the recent SPA 60th
Anniversary Convention), UV/IR filter and a deep sky OIII filter when
taking images of the Sun with a Canon D550 DSLR and 80mm f11 refractor.
The OIII filter is said to act like a solar continuum filter and when
ombined with a UV/IR rejection filter helps to improve the clarity of
digital solar images.

Rotation Nos. 2142 - 2143
There a significant rise in sunspot number in October, compared to the
previous two months, and we had at least one, possibly two, naked eye
sunspots. The Mean Daily Frequency went up from 2.80 last month to
5.10 this month and the Relative Sunspot Number more than doubled from
35.47 in September, to 71.65 this month.

The first few days of October showed limited sunspot activity. AR1855,
AR1856 and AR1857 were seen on the 5th, the first was nearing the W
limb, and the second and third were still some way from the SE limb.
As AR1857 approached the W limb it was followed by AR1861, AR1864 and
AR1865 coming over the SE limb and putting on a fine display by the
10th. All three Active Regions showed signs of growth by next day. On
the website announced that AR1861 and AR1865, by
then near the CM, were active with low-level C class flares due to
their sunspot configuration.

From mid-month onwards sunspot activity really picked up. AR1875 and
AR1877 were seen near the SE limb on 19th. AR1875 was visible to the
naked eye on the 24th was remained so even as it neared the NW limb on
the 27th. The main spot showed a bright patch of photosphere with a
trail of smaller spots behind it. AR1877 was possibly visible to the
naked eye as well. AR1882 was much further east, towards the SE limb,
and had about 16 umbrae embedded within the penumbrae. A patch of
bright photosphere was also seen in the centre of the main spot. On
the same day AR1884 and AR1885 were just over the SE or E limb and
showed faculae being close to the limb. By the 30th the Sun was again
very active, AR1882 was now at the CM behind a very complex group
AR1885 and AR1879 coming over the E limb with bright faculae scattered
around the two main sunspots.

MDF: 5.10 R: 71.65

On the 5th plages and filaments were seen around AR1856 and AR1857 and
a group of bright lengthy prominences were seen on the E limb. There
was a substantial hedgerow prominence on the 7th. Numerous plages and
small filaments were seen around AR1861, AR1864 and AR1865 on the 10th
as were prominences along the S, E and W limbs. A broad dense
prominence was also seen at the NW limb the following day. On the 15th
a substantial prominence was seen at the S limb and a sizable arch
prominence on the NW limb. Meanwhile AR1861, AR1864 and AR1865 still
showed plages and filaments near them.

The 17th saw some large and diverse prominences as well as spikes
particularly along the SW limb, extending eastwards. AR1875 and AR1877
each showed several plages nearby and AR1877 had a large coiled
filament just east of it on the 24th. Also seen on that same day were
some filaments at the SE and SW limbs and there were several sizeable
prominences visible. On the 25th a long curved filament was observed
passing through AR1875, prominences and spikes were seen on the N and
W limbs, and a bright highly active prominence on the SE limb. On the
31st several dark conspicuous filaments were seen near the E limb as
well as a tree-like prominence on the W limb.

MDF (P): 7.18

Go to the Solar Section link on the SPA homepage to see a selection of
the many remarkable images and drawings made by the Section membership.

Bulletin compiled by Clive Down
(c) 2014 the Society for Popular Astronomy

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
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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