Download Volume 1 (Issue 6), June 2012

SUPARCO - ASTRONOMY & ASTROPHYSICS
BULLETIN
Volume I, Issue 6
Pakistan Space Vision 2040, was
approved by the Prime Minister of
Pakistan which inter-alia included
augmentation / strengthening of
the Astronomy and Astrophysics
programmes of SUPARCO.
SUPARCO`s
astronomy
and
astrophysics program is mainly
focused on theoretical and
observation research. For this an
astronomical
observatory
is
planned to be established.
Research studies pertaining to
deep space objects including
galaxies, nebulae and variable
stars are also being initiated.
Search for earth like planets is a
hot
topic
in
astrophysics
nowadays. It is planned to conduct
research studies in this field also.
Inside this Issue:
The phenomenon
of Transit
Red Giant Stars
Book Review
The Phenomenon of Transit
Transits are among the events which are observed with interest by astronomical
community all over the world. Transit means the passage of one astronomical
body (smaller in apparent size) across the face of another astronomical body
(bigger apparent diameter), shadowing a portion as seen by an observer from a
vantage point in space. Another meaning of transit is the crossing of an
astronomical object over the meridian of the observer.
The most common transits occuring every
month are the satellites (moons) of Jupiter and
Saturn passing over the faces of the planets
as seen from the Earth. The picture to the right
shows one of such a transit of Io, Jupiter’s
moon. Io can be spotted at the center of the
image whereas its shadow can be seen on the
dense, cloudy atmosphere of Jupiter.
Sometimes there are transits of man-made
objects across the faces of astronomical
bodies including the Sun and the Moon,
especially. Amateur astronomers are very
Transit of Io over Jupiter. the
keen in observing and photographing such shadow of Io can also be seen on
the cloudy surface of Jupiter
rare events. Such events last only for few
seconds and thus require high level of
expertise in telescope and camera operation
to catch the glimpses of a satellite passing
over the face of an object.
Ecliptic
This remarkable picture taken by an amateur
astronomer showing the partial solar eclipse
of 4th January 2010 along with the transit of
the International Space Station (ISS), in an
orbit around the Earth. A sunspot at the lower
right limb on the solar disk can also be seen.
Sky this Month
Web Review
Software Review
Addional Ionozation by
Meteor Shower
Meteorite found in
Tharparker
Pass of ISS over Sun during partial
solar eclipse of Jaunary 4, 2012
9
Events of the Month
Date
Time
06 Jun
After
Sunrise
Before
Sunrise
17 Jun
20 Jun
21 Jun
27 Jun
-
June, 2012
Event\Direction
Transit of Venus\ East
Moon, Jupiter, Venus\ East
June Solstice
After
Sunset
New moon, Mercury,
Castor and Pollux
After
Sunset
Mars, Saturn
& Quarter moon
Transit of Venus
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
The inferior planets, Venus and
Mercury, accordingly are the planets
for which we see transits. However, as
seen from outer planets such as Mars,
Jupiter etc, the Earth itself transits the
Sun. While transits of Mercury are
relatively common, occurring once or
twice every decade, the transits of
Venus are extremely rare, occurring
less than twice a century. The first ever
observed transit of Venus was in 1639,
and since then, only 5 transits of Venus
have occurred, the last one in 2004.
Page II
The next transit of Venus occurs June 6, 2012, and
then not again until 2117.
On 13th November 1986, there was a transit of
Mercury at the solar disc as seen from Earth at 0745
hours (PST) and continued its apparent travel until
1130 hours (PST). SUPARCO scientists tracked its
path over the solar disc and captured a series of
photographs of this event.
Astronomical Unit today, but it is instructive to learn
how the old methods worked.
A transit of Venus across the Sun takes place when
the planet Venus passes directly between the Sun and
the Earth, becoming visible against the solar disk.
During a transit, Venus can be seen as a small black
disk moving across the face of the Sun. The duration
of such transits is usually measured in hours. A transit
is similar to a solar eclipse by the Moon. While the
diameter of Venus is almost four times that of the
Moon, Venus appears smaller, and travels more
slowly across the face of the Sun, because it is much
farther away from Earth. Observations of transits of
Venus helped scientists use the principle of parallax to
calculate the distance between the Sun and the Earth.
The principal events occurring during a transit are
characterized by four contacts. The event begins with
contact I which is the instant when the planet's disk is
externally tangent with the Sun. The entire disk of the
Venus is first seen at contact II when the planet is
internally tangent with the Sun. During the next
Transit of Mercury , November 1986 as observed by
several hours, Venus gradually traverses the solar
SUPARCO
disk at a relative angular rate of approximately 4
In June 2004, first of the pair of transits of Venus for arc-min/hr. At contact III, the planet reaches the
21st century occured. This transit of Venus was opposite limb and is once again internally tangent with
observed by the scientist to refine their techniques to the Sun. The transit
2005 Annular
ends atSolaco
contact IV when the
search for extrasolar planets.
planet's limb is externally tangent to the Sun.
Contacts I and II define the phase called ingress while
contacts III and IV are known as egress. Greatest
transit is the instant of minimum angular separation
between Venus and the Sun as seen from Earth's
geocenter.
Transit of Venus on June 8, 2008; the first of the pair for
21st century
Despite being so rare, transits of Venus have
played an important role in the history of
astronomy.
Many
governments
organized
elaborate and expensive expeditions to remote
parts of the globe so that astronomers could view
the transit from several different sites during Venus
transit of 1761, 1769, 1874 and 1882. The main
reason for such interest was that transits of Venus
provided a unique opportunity to determine the
length of the Astronomical Unit, which is the
average distance between the Earth and the Sun, a
fundamental scale in the universe. We have easier
and more precise methods of determining the
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Event
Universal Time
Position Angle
Contact I
22:09:38
41°
Contact II
22:27:34
38°
Greatest
01:29:36
345°
Contact III
04:31:39
293°
Contact IV
04:49:35
290°
Contact timings for transit of Venus 2012
Visibility of 2012 transit of Venus
The entire transit (all four contacts) is visible from
northwestern North America, Hawaii, the western
Pacific, northern Asia, Japan, Korea, eastern China,
Philippines, eastern Australia, and New Zealand. The
Sun sets while the transit is still in progress from most
of North America, the Caribbean, and northwest
South America. Similarly, the transit is already in
progress at sunrise for observers in central Asia, the
Middle East, Europe, and eastern Africa. However
the transit will not be visible from Portugal or
southern Spain, western Africa, and the southeastern
2/3 of South America.
Page III
2012 Transit of Venus in Pakistan:
The sunrise timing for 6th June for Karachi is 05:44
PST. By this time, Contact I and Contact II of transit of
Venus will already have been passed and Venus would
be close to its minimum angular separation with the
Sun, an event that will occur at 06:29:36 PST. Contact
III would occur at 09:31:39 PST when Venus would be
tangent to the other limb of the Sun and the last contact
will at 09:49:35 AM when Venus will be at the outer
tangent to the surface of Sun.
Transit of Venus; Just after Sunrise
Contact III
Contact IV
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Don't Miss the Transit of Venus in 2012: It's Your
Last Chance Until 2117
As the 6th June is coming near, people around the
world are preparing for this last in a lifetimes event.
Astronomers are travelling to the sites where the
visibility of transit would be the best. Scientific
organizations are arranging different public
gathering for promoting astronomy using this event.
Some are even preparing to broadcast the event for
general public. What are other ways through which
public can witness this celestial event? Eclipse
shades and sunlight filters can be use to safely view
the sun. But since the diameter of Venus would be
around one arc min, it would be difficult to observe it
with eyes. The better options are using magnifier
with filters. Back view projection technique can also
be used to project the image of the sun onto a white
screen with the people gathering around the screen
watching the transit.
In this era of technological revolution, for those
places where transit would not be visible entirely or
there are no means of observing the transit, an
iphone application of transit of Venus is now
available that can be used to observe transit at your
palm. This application has been designed to inspire
international collaboration during the 2012 transit of
Venus by enabling a digital re-creation of those
global expeditions. The phone app will allow citizens
around the world to witness this rare phenomenon
and to contribute their observation to a collective
experiment to measure the sun’s distance.
To have extended utility, the phone app will serve
before, during, and after the transit. Prior to the
transit, one can practice timing the interior contacts
using a simulation of the transit. Additionally, one
can see predicted times of contact for one’s location.
During the transit, the phone app will assist in
measuring the time of the interior contacts. This
application
can
be
downloaded
from
www.transitofVenus.org
The last time pair of transit of Venus occurred on
Dec 09, 1874 and Dec 06, 1882. At this time no one
had ever imagined that by the next pair of transit of
Venus people would be using much sophisticated
ways and technology for viewing transit of Venus. By
the end of this transit of Venus, humanity would have
to wait more than 105 years to witness another
transit of Venus and who knows at that time what
revolutions would have occurred in science and
technology.
Page IV
Red Giant Stars
Red giant is evolved by converting most of its
hydrogen to helium by thermonuclear fusion. Red
giant is greater luminosity star and has a diameter
of 10 to 100 times the Sun with surface temperature
below about 4000 K.
Internal Composition of Red Giant Star
HR diagram illustrating the evolution of stars into
different final stages
Formation of red giant star
In the beginning, stars generate energy fusing
hydrogen atoms into helium by thermonuclear
fusion process. The process of fusing hydrogen
into helium continues for billions of years and
eventually exhaust the hydrogen at the core of a
star. In the absence of energy flowing out from a
star to counterbalance the inward force of gravity,
the core collapses and the hydrogen that remains
in a shell around the core of star begins to burn
and causes increase in luminosity of star. As core
collapses, the outer atmosphere layers of star
expand outward. This expansion cools the
surface layers turning star it into red giant.
The expansion of outer layers of star drops its
surface temperature and extends star radius tens
to hundreds times larger than radius of the Sun.
Meanwhile, the temperature in the collapsing core
ascends, becoming hot enough in some stars to
start fusing the helium atoms into carbon and
carbon into other heavier elements. This can only
happen in stars comparable in mass to the Sun
and greater; less massive stars cannot become
hot enough in their cores of begin fusing helium,
and they eventually fade out when their last
reserves of hydrogen and helium exhausted.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
The stars having mass 10 to 70 solar mass during their
red giant phase become “red supergiants”. Red
supergiant stars may have luminosity million times
greater than the Sun. These are very massive stars
seen just before their supernova stages. Betelgeuse,
Antares and Arcturus are the best examples.
Betelgeuse Red Supergiant Star (Constellation
Orion)
There are stars which do not enter red giant phase are
called Red dwarf stars having mass less than 0.35
solar mass. They transport energy from center to
surface through convectional process, mixing helium
produced at their cores throughout the rest of their
bodies. As a result, these stars do not gather an inert
core of helium and are predicted to exhaust all of their
hydrogen fuel without ever becoming red giants. The
Page V
Book Review
expected lifetime of these stars is much greater than
the current age of the universe.
Fate of Sun as a Red Giant:
Unlike the other heavier stars, the Sun does not
possess enough mass to explode as a supernova.
The sun has passed about half of its life period. In
about 5 billion years, it will enter a red giant phase. Its
outer layers will expand as the hydrogen fuel at the
core is exhausted and the core will contract and heat
up. Hydrogen burning will continue in a shell
surrounding helium core, which will gradually expand
as more helium is produced. The surface temperature
of the Sun would reduced as outer layers of the Sun
expands. The hydrogen burning shell will increase the
Sun luminosity and Sun will become red giant star.
The sun would be up to 250 times its current size due
to its outer layers expansion, as big as 1.4 AU and will
swallow up the Mercury, Venus, Mars and the Earth.
Finally when the core temperature reaches around
100 million Kelvin’s, helium fusion at the core will begin
producing carbon and oxygen. The intense thermal
pulsations will cause the Sun to throw off its outer
layers, forming a planetary nebula around degenerate
dense carbon and oxygen core which is then called
White Dwarf.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
There is nothing more satisfying than making a
telescope and using it to observe the star-studded
sky. As the name of the book suggests, Making
and Enjoying Telescopes, is surely a gift and worth
an asset for enthusiasts and amateur astronomers
alike. Written by Robert Miller and Kenneth
Wilson, the book contains eight chapters giving
information from the history of telescopes to
amateur telescope makers. Along with these
chapters, there are six complete projects for
building small telescope up to 10 inch diameter
(Primary Mirror). Not only reflectors are shown
how to build but also one of the very famous
design amongst amateurs i.e. the Dobsonian
Mount 10 inch telescope is featured. Appendices
contain some technical information about correct
placement of diagonal mirror (secondary mirror)
and some basic formulae necessary to use in
telescope construction. Those university students
who are undertaking a project may find this book
as an important source, if they choose to build a
telescope.
Page VI
Sky this Month
June 4, 2012 - Full Moon
Earth will be between the Sun and Moon, and
therefore, the Moon will be fully illuminated as seen
from Earth. This phase takes place at 11:12 p.m.
UT.
June 05, 06, 2012-Venus transiting the Sun
This rare event will be entirely visible mostly in East
Asia, eastern Australia and Alaska. A partial transit
can also be seen in progress at sunrise throughout
Europe, West Asia and East Africa. A partial transit
can be seen in progress at sunset in most of North
America, Central America, South and West
America. It will not take place again until 2117.
June 17, 2012- Moon, Jupiter, Venus and
Pleiades Cluster at Dawn
This congregation of the two planets, Jupiter and
Venus, moon at the edge of being new moon and
visually appearing an open cluster of seven stars
called Pleiades would be visible at around dawn on
June 17. This view will be visible in the eastward
direction, but being close to horizon, observers may
have some difficulties in spotting the objects. Very
close to horizon a reddish color star called Aldebran
in constellation Taurus and a bluish white star
Capella can also be observed in the same direction.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
June 20, 2012 - June Solstice
June solstice occurs at 23:09 UT. North Pole of the
Earth will be tilted towards the Sun, which will reach
the northernmost position in the sky. This is the first
day of summer (summer solstice) on the northern
hemisphere, and the first day of winter (winter
solstice), in the southern hemisphere.
June 21, 2012- New moon, Mercury, Castor and
Pollux at dusk
At the dusk of June 21, a kind of sinusoidal shape can
be seen made by the objects including Procyon, a
yellowish star; then new moon; then Mercury and
finally then Pollux and Castor, the two brightest stars
of constellation Gemini. This view would be visible in
the West direction.
June 22, 2012 - New Moon
Moon will be directly between Earth and Sun and will
not be visible from Earth. This phase takes place at
15:02 UT.
June 27, 2012- Mars, Saturn and the quarter moon
At the 8:00 PM local timings on June 27, Saturn and
the Mars would have their appearance in the
southern sky with quarter moon nearly in between
these two planets. It would be a nice show of colors in
the night sky with Saturn appearing yellowish then
moon with its glittering white light and then Mars,
strongly reddish in its appearance.
Page VII
Web Review
Software Review
HubbleSite is a truly a wonderful website providing
various services at the same time all that related to
Hubble Space telescope. Bringing the magnificent
images from the Hubble Space Telescope (HST)
back down to Earth, HubbleSite is the place for all
things. The NewsCenter service provides updated
information about what’s going on with Hubble
Telescope and other astronomical news as well.
Apart from this, one can also find information about
the discoveries of HST or just learn more about the
telescope itself.
HST all time masterpieces are also there for viewing
and the site goes all-out with the images. One can
also download wallpaper, watch videos in the movie
theater, and take image tours. It’s all available in the
gallery section.
Starry Night is planetarium software with realistic
imagery and real time appearance of the sky and
other astronomical phenomenon including past and
future appearance of object in the sky. Initially
developed by Sienna Software, Starry Night now
owned and developed by Simulation Curriculum
Corp. this software is available for both Macintosh
and PC(Windows) operating system. An iPhone
application of Starry Night is also available although
the recent versions of the software specially target
the amateur community with features like
observation planning, telescope control and
multiple-panel printing.
Starry night is using the Hipparacos Catalogue, the
Tycho-2 Catalogue, and the Tully catalogue of
galaxies for its data base. It has options of viewing
the night sky from any location on Earth or viewing
the Earth from any location of the solar system or
even viewing the Milky Way and other nearby
galaxies. Time lapse can be made fast or slow at
your own convenience. One can also calculate
ephemerides of solar system objects, generating
Hertzsprung-Russell diagram of stars and also
displaying current imagery of solar and Earth
observing Satellites.
The software can also be interfaced with laptops and
computers, using GOTO telescopes through this
software. Starry Night has different versions,
available right now, from a beginner to a student
version and from astronomy enthusiast to advanced
amateur astronomy version. Although a commercial
software, Starry Night can be a wonderful beginning
for those who are enthusiastic about astronomy.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page VIII
Additional Iononization by Meteor Shower in the Ionosphere
Our Earth is surrounded by several gases and water vapours which make the life possible on the Earth. The
atmosphere of the Earth has different layers depending upon the concentration of air molecules, altitude,
temperature, pressure and other parameters. These layers are troposphere, stratosphere, mesosphere,
thermosphere and exosphere. All these layers have been defined in the neutral atmosphere; however, the
upper atmospheric layers get ionized due to the solar extreme ultraviolet radiation and x-rays. This ionized
region is called ionosphere which ranges from 60km – 1000km in altitude. This is where free electrons and
ionized molecules are found and these electrons support the long range radio communication over the entire
globe.
The ionosphere is further divided into
designated regions as D, E, and F. The D and
E-layers both disappear at local night due to
the absence of sun whereas F is a 24/7
existing layer. SUPARCO being the national
space agency of Pakistan monitors the
behaviour of ionosphere using three
monitoring stations, one each at Sonmiani,
Multan and Islamabad. The instrument used
for the purpose is called digisonde which is
basically a radar system.
Earth’s Atmospheric layers
There is a special layer of the ionosphere which is present in the E-region and is called the sporadic E layer
or ‘Es’. It may occur any time of the day at an altitude of about 100km. The lifetime of the sporadic E
depends upon the latitude and it can last from a few minutes to several hours. Long range communication
can be possible due to this highly ionized cloud but it is unreliable as the existence of sporadic E is not
guaranteed throughout the day.
One of the several causes of formation of Es is a meteor shower. Meteorites are generally composed of
metallic ions which play an important role is ionizing the E-layer and uneven patches of excessive ions form
randomly at the time of meteor shower. Strong existence of Es was observed at Multan during night of 4th
& 5th May 2012. This was the time when Eta Aquarids occurred on the full moon night. Eta Aquarids is one
of the well defined meteor showers associated with Halley’s Comet. On the same night a meteorite was
found in Tharparkar district as mentioned in this bulletin.
The figure shows an ionogram (output of digisonde) which is a frequency in MHz (x-axis) versus height in
km (y-axis) profile of the local ionosphere monitored at Multan during the mentioned night. The horizontal
coloured pattern at 100km shows the existence of the sporadic E layer.
Es layer observed at Multan on the night of May, 4 2012
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page IX
Meteorite found in Tharparker
On the midnight of May 4, 2012, the time when Eta Equarids meteor
shower was at its peak, a meteorite was reported to have fallen in a
village of Tharparker, called Ladki. It was a small meteorite weighing
around 100 grams. The meteorite was then transferred to a nearby
small city called Diplo where its news was broken by a local
newspaper. Later on, this meteorite was formally handed over to a
team of SUPARCO officials. A search in nearby areas where the
meteorite was reported to have fallen was also undertaken by
SUPARCO researchers to recover any other pieces, but none were
found.
Facts
about
Meteorite:
Small crater produced by the
Meteorite
Falling
The piece of the meteorite
handed over to SUPARCO
weights 73 grams with density
3.51 grams/ml. The miniral
content ofthe meteorite were
Iron, Nickel, Cobalt, Zinc. Iron is
found to have the largest
percentage of all constituent
particles which is 11%. That
means out of 73grams, 8 grams
is the Iron contents making
meteorite
magnetic
and
susceptible
to
magnetic
materials.
Although an extensive research
is still need to be done in which
meteorite class would be found
that will ultimately suggest its
name according to international
standards. This research would
also recognize this recovery of
meteorite in Pakistan according
to the rules of Institute of
Meteoritic
(IOM)
and
International
Meteoritical
Society (IMS).
Meteorite found in Tharparkar
Schematic diagram illustrates the
formation of the classic strewn
field. When a meteoroid enters the
upper atmosphere along an
inclined
trajectory,
great
decelerating forces usually cause
it to break into tens, hundreds, or
even thousands of pieces. The
smaller pieces slow down more
quickly than the larger pieces.
When they hit the ground they
distribute themselves within an
elongated ellipse with the smaller
pieces at the near end and the
larger heavier pieces at the far
end. Crosswinds can severely
alter this pattern.
Contact Information
A metallic or rocky small body orbiting the sun in space; small particles that may derive from comets; larger (1 cm or larger)
particles that probably derive from the asteroid belt. Meteoroids seen passing through an atmosphere are called meteors, and
if they survive to land on the surface, they are called meteorites. Small meteoroids are also often called interplanetary dust
particles (IDPs). Sunlight reflecting off this material gives rise to the zodiacal light.
Rizla Zareen
General Manager
Gulzar-e-Hijri SUPARCO Road
Sector 28, SUPARCO, Karachi, Pakistan
Tel: 021-34690765-74
Fax 021-34690795
Email: [email protected]
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
This bulliten can be downloaded from the official website of SUPARCO