Astronomy
is oldest of the natural science that comprising to the early human ancestors,
Astronomy, celestial mechanics and the study of universe beyond the Earth’s
atmosphere is that Astrophysics. Astronomy is easy to understand how these
thousands of lights in the sky have affected people throughout the ages. Among
them modern astronomy is the fundamental science, motivated mainly by man’s
curiosity, his wish to know more
about the nature
and universe. Astronomy can be divided into different branches in
several ways of research, spherical or positional. Astronomy studies the
co-ordinate system on the celestial sphere, their changes and the apparent
places of celestial bodies in the sky. Celestial mechanics study the movement
of bodies in solar system, in stellar system and among the cluster of galaxies
and galaxies. It can be divided into different areas like as radio waves, infrared, ultra violet, X-ray, gamma ray
which has depends upon wavelength of electromagnetic spectrum are used in
observations. For the solar system is governed by the sun which produces energy
in its centre by nuclear fusion. The sun is our nearest star and its study
lends insight into conditions on other stars.1
1.1
Infrared
Astronomy
Infrared
Astronomy is the detection and study of the infrared radiation (heat energy)
emitted from object in the universe .Infrared Astronomy was introduced in
Hungary byLajosG.Balazs in the 1980s when he to analyze and interpret IRAS data
the Konkoly observatory Budapest 2. All object emit infrared radiation, so
infrared Astronomy involves the study of just about everything in the
universe.In the field of
Astronomy,
the infrared region lies within the range of sensitivity of infrared detectors,
which is between wavelength of about 1 and 300 microns. The living beings
(mostly human) eye detects only 1% of light at 0.69 microns and 0.01% at 0.75
microns which is very effectively, we cannot see wavelength because the light
source is very bright.Infrared is divided into
three parts i.e. near, mid and far infrared. Near infrared refers to the
part of the infrared spectrum that is closest
.
Figure1:Visible (courtesy of Howard Macallon), near
infrared(2mass) and mid infrared(ISO) view of the Horse head Nebula ,image
assembled by Robert Hurt. 3
to visible light and far – infrared
refers to the part that is closer to the microwave region. Mid-infrared is the
region between these two.
Infrared Astronomy has been great
significance to peer through the veil of interstellar dust, which blocks light
in the visible wave length of the electromagnetic spectrum. It is able to do
this that’s why light in the infrared region pass right through interstellar
dust, completely unaffected, thus enabling us to see objects whose light would
normally be blocked from our view, and again enables us to see at extreme
cosmological distances that is galaxies in the early universe, the light of
which is so red- shifted that they are visible in the infrared only.4
2.
Literature Review
2.1
Flarestar
A
variable star which has unpredictably have a massive increases in its
brightness across the electromagnetic spectrum for a few minutes and similar to
the solar flares, they are magnetic disturbances in the atmosphere of stars.
The brightness increases across the spectrum from x-ray to radio waves.
The
first known discovered flare is V1396 CYgni and at microscopic but the best
known flare star is UV Ceti.Flare star classified as UVCeti type variable stars
in variable star catalogues. Flare can happen once every few days much less frequently (in case of Barnards
star). The nearest star to the solar system is ProximaCentauri which is also a
flare star. Generally red dwarf star are called flare star but little to be possible for brown
dwarfs.The more massive RS
CanumVenaticorum variables are also known to flare but scientist understand
that a companion star disturbs the magnetic
field . this companion is amassive planet like the planet Jupiter that orbits the flaring star closely which is observed to
the outburst.5
Figure
2: Schematic diagram of a solar flare red and blue lines represent magnetic
fields carrying solar material of the surface flares occur when these field
lines meet and reconnect producing hug explosions and heating and acceleration
of solar material credit.: NASA Mashall
Space Flight Center.6
After
the forming offlare mechanism can be
explained by an alpha ohm dynamo,
a combination of connective motion and differential rotation which power the
magnetic field. The magnetic field is
linked to the plasma of the star. At these distances the plasma becomes thin
and there is evidence that the magnetic field is no longer linked to it. If the
magnetic field becomes stronger, the magnetic field lines recombine and relief
energy a flare occurs.5
2.2
Spitzer
survey
When
we present infrared array camera (IRAC, similar to 2deg (2)) and multiband imaging photometer for Spitzer (Mips, similar
to 8deg(2)) observation of the Cepheus flare , which is associated with the
Gould belt at an approximate distance of similar to 300pc.Around 6500 sources
are detected in all four IRAC bands of which similar to 900 have MIPS 24MU, we
identify 133 young stellar object candidates using color magnitude diagram
techniques and a large number of the YSO candidates are associated with the NGC
7023 reflection nebula. For the nearest neighbor clusteringanalysis identified
four small protostellar groups (L1228, L1228N, L1251A and L125B) with 5-15 members each and the
larger NGC 7023 associated with 32 YSO members. The star formation efficiency
for cores with cluster of proto stars and for those without cluster was found
to be similar to 8% and similar to 1% respectively.7
2.3
Dust and Grain
In flare star researchers believe
they have identified the main source of cosmicdust gets dumped on earth – meteoroids. Cosmic
dust is also known as space dust as well as extraterrestrial dust. A new study
shows that grains of dust left in meteoroid trails are larger than previously
thought. Some make their way to earth and buzz through the atmosphere, leaving
fiery streaks known as shooting stars, along with clouds of dust particles.
After the long time these particle were just a few nanometers in size but the
such particles are actually 10 to 20
micrometers in recent by the study of university of Australia.Finally theseparticle
drifted down to the troposphere and may have been washed out by rain.8
2.4
AKARISurvey
Akari
formally known as ASTRO-F, is the second space mission for infrared astronomy
from the institute of space and Astronautical science (ISAS) of the Japanese
Aerospace exploration agency(JAXA). It was ESA participation.9
3.
Objectives
The objectives of my dissertation
work are as follows
·
We intend to perform a systematic search on far infrared loops
reported by kiss et al. (2004) and Koenyves et al.(2007) to find an isolated
cavity(flare star cavity) and its possible association using AKARI surveys. The
cavity which was not studied before will be taken into consideration for
further study.
·
The physical properties of this cavity
will be studied and the size, distance, dust color temperature and energy
required to expel then it will be calculated.
·
We are interested to find out the
possible sources between the flare star cavity and ISM, as well as the
structure of shaping mechanism will be studied.
·
The evolution of the flare star cavity
and the structure will be discussed using published literatures. The possible
explanation of the result will be presented.
4.
Research
methodology
A explanation of the method and method of analysis is given below
Systematic
Search
(AKARI)
Far
Infrared Cavity Selection
(SIMBAD
& ADS)
Contour
Map Correction(ALADIN)
Study of
Flux Density Variation
(ALADIN)
Distance
Angle
Estimation
Dust
Color Temperature Calculation
Study of
possible flare star
Study
of ShapingMechanism
Explanation
& Comparison of the result
Figure 3:A scheme of method
of study and analysis
At first we examine region of
interest and then study the physical properties of flare cavity. Here, AKARI
represent the name of all sky infrared surveys, SIMBAD is the French
abbreviation of galactic point sources database provider maintained by
Starsburg University, France, ADS is the literature data base provider
maintained by Harvard University, USA. The ALADIN is the data reduction
software provided by NASA, USA.
4.2
Dust
Color Temperature
We worked on selected far infrared cavity at 90 and
140 micro meter AKARI maps using
ALADIN software to find flux densities as described in Shnee et al. (2005). The
dust color temperature
can be obtained by assuming that the
interstellar dust in a single beam is isothermal and that the observed ratio of
90 and 140 micro meter emission is due to black body radiation from dust grains
at particular temperature. The flux density of emission at a wavelength
is given by
(1)
Where
is the column density of dust grains, which is
a constant, ? is the spectral emissivity index, and
is the solid angle subtended at
by the detector. Following Dupacet al. (2003), we use the relation
(2)
To describe the observed inverse relationship
between
and ?, Here
and
are free parameters found that the temperature
dependence of the emissivity index fits very well with the hyperbolic
approximating function, with the assumption that the dust emission isoptically
thin at 90 µm and 140 µmand that
(true for IRAS image), we can write the ratio
“R” of the flux densities at 90 µm and 140 µmas,
(3)
The value of ?
depends on dust grain properties as composition,size and compactness. For
reference, ? =0, ? ~1 and ? ~2 for pure black body, the amorphous layer
–lattice matter and the metals and crystalline dielectrics respectively. For a
smaller value of
1 can be dropped from both numerator and
denominator of equation and it takes the form
R =
(4)
Taking natural logarithm on both
sides of equation (4) we find the expression for the temperature as,
(5)
Where,
R is given by, R =
(6)
F(90 µm) and F(140 µm) are the flux
densities at 90 µm and 140 µm, respectively. In this way we can equation (5)
for the determination of the dust grain temperature. 10
4.3
Preliminary
works: systematic Search for Flare star
For
the efficient analysis iscarried out in the Sky View Virtual Observatory on154
far infrared KK-loops accounted by Kiss et al. (2004) and Koenyves et al.
(2007) at 90 and 140 micron AKARI maps. on the source of blind examination and
SIMBAD/ADS database, I have preferred region of interest shown below for the
further learning
Figure 4: A 20 x 2oAKARI’S
images at WIDE-S (left) and WIDE-L (right) AKARI maps are shown. All images are
centeredat I(G)=0.5 and I(G)= 69.5 in J2000 coordinate with stern special
coloring .The darkest color symbolize the region of minimum flux density, and
the brightest the maximum flux density.
When we obtain, FITS(flexible image
transport system) image of the region of interest will be down loaded and
practiced in the ALADIN9.0 software presented by NASA Extragalactic Database
centre. The contour maps, In each pixel of values of relative Fluxdensity can be calculated from that software and then
similar to the next coordinate steps. Finally we will determine the dust color
temperature from previous images of
AKARI.
5.
Expected
Outcomes
The anticipated
outcome will be given as
·
By the formation of far infrared loops
and flare cavity in thegalaxy will be offered and discussed with the published
literatures. The role of far infrared loops is projected to be significant for
the interstellar dust, i.e. mixture of carbon and silicon compounds.
·
We imagine to locate the reason of star
construction in the far infrared sky.
6.
Work
Plan
Our work plan for 12 month are as given below
Work
1-2
month
3-4 months
5-6
Months
7
month
8
Month
9
Month
10
month
11-12
Months
Literature
Review
AKARI
Survey
Problem
Identification
Image
Reduction
Calculation
& plotting
Modeling
& Fitting
Multi-wavelength
Study
Interpretation
Thesis
Writing
7.
References
1
H. Karttunen, P. Kroger, H. Oja, M. Poutanen, K.J. Donner (Eds.),FundamentalAstronomy,5th
Edition, Springer-Verlag Berlin Heidelberg, (2006)
2L.
V.Toth,S.Zahorecz,C.Kiss,Infrared
Astronomy, Eotvos Lorand University,(2013)
3 www.ib3health.com/product/…mid_and_far_infrared.shtml,
(Viewed onNov, 2017)
4B.Aryal,
C.Rajbahak, R.Weinberger, Mon. N. R.Astron.Soc.,402, 1307, (2010)
5http//sussle.org/t/
flare-star (Viewed on Nov, 2017)
6
https//www.aavso.org/vsots_uvcet, (Viewed on Nov, 2017)
7J.Kirk.,
M. D. Thompson, E.Allen. The Astrophysical
Journal,185 , 1,198, (2009)
8https://www.space.com/1484-source-cosmic-dust.html,
(Viewed on Nov, 2017)
9Sci.esa.int/astrophysics/55873-akari-infrared-all-sky-data-released, (viewed on
Nov,2017)
10
X.Dupac, J.P. Bernard, N. Boudet, M. Giard, J.-M. Lamarre, C. M’eny, F.Pajot,
I. Ristorcelli, G. Serra, B. Stepnik,and J.P. Torre, Astronomy & Astrophysics,404,
L11 (2003)
Supervisors
…………………………..
Prof.
Dr. BinilAryal
HoD,
CDP, TU, Kirtipur
………………………………….
Mr.
A.K. Jha
CDP,
TU, Kirtipur
……………………………………
Prof.R.Weinberger
Innsbruck
University,Austria
