Transcript GEARS Workshop Monday - Georgia Southern University

GEARS Workshop Wednesday
Don’t forget there are hidden
slides and notes – don’t just use
the2011
show
Warm Up
• Online – and paper evaluation –
• Discuss how spectroscopy provides
information about the motion of objects.
• Characterize the habitable zone in solar
systems.
• Please use what is in your own brain only.
Overview Slides
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Great Observatories
Stellar Evolution recap
Introduction to imaging
Ds9 introduction and spectral line
identification
• Atmospheric transparency
Outcomes – from AstroGPS
• Identify end phases of stars like the sun
• Match evolutionary stages to initial mass
ranges
• Relate atmospheric properties to astronomical
equipment needed
• Relate mass of star to lifetime and power
• Correctly identify colors and luminosities of
stars using an HR diagram
NASA’s Great Observatories
• http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic
_reference/greatobs.html
• http://www.nasa.gov/audience/forstudents/postsecondary/fe
atures/F_NASA_Great_Observatories_PS.html
• Today we are going to look at some of the data from Chandra.
• The next 2 images are examples of what you can do with
observations at multiple wavelengths of same part of sky
HST + Chandra
Spitzer + HST + Chandra
Stars
• We’ve spent some time looking at properties
of blackbodies and learning how to learn
about astronomical objects that we can’t get
close to
• Temperature and color
• Temperature and overall luminosity
• Inverse square law of flux -> observed
brightness
“ordinary” Sun
• Hydrogen fusing to Helium
• Main sequence = adulthood for stars
• Sun surface = 6000 K = peaks in visible light
(recall people = 300 K = peaks in infrared
light)
Red Dwarf
• Proxima
Centauri
• X-ray image
• DIM in x-rays
• So Must be close!!!
Brown Dwarf = not quite
main sequence
Star Formation
• What are some of the things you notice about
places where we find young stars?
Star Formation
Eagle – M16
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A new look at the famous "Pillars of Creation" with NASA's Chandra X-ray
Observatory has allowed astronomers to peer inside the dark columns of gas and
dust. This penetrating view of the central region of the Eagle Nebula reveals how
much star formation is happening inside these iconic structures.
The Chandra data shows bright X-ray sources in this field, most of which are young
stars. In this image, red, green, and blue represent low, medium, and high energy
X-rays. The Chandra data have been overlaid on the Hubble Space Telescope image
to show the context of these X-ray data.
Very few X-ray sources are found in the pillars themselves. This suggests that the
Eagle Nebula may be past its star-forming prime, since young stars are usually
bright X-ray sources. However, there are two X-ray objects found near the tips of
the pillars. One is a young star about 4 or 5 times as massive as the Sun, visible as
the blue source near the tip of the pillar on the left. The other is a lower mass star
near the top of the other pillar that is so faint it is not visible in the composite
image.
M16 – xray stars
End of Stars
• Main sequence is the stage of existence where
stars are fusing hydrogen to helium
• Spend largest fraction of their existence doing
this
• More massive stars – short lived
• Low mass stars – long lived
• Range – 100,000 years – 100 billion years!
Star Formation
• What are some of the things you notice about
places where we find young stars?
Star Formation
Eagle – M16
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A new look at the famous "Pillars of Creation" with NASA's Chandra X-ray
Observatory has allowed astronomers to peer inside the dark columns of gas and
dust. This penetrating view of the central region of the Eagle Nebula reveals how
much star formation is happening inside these iconic structures.
The Chandra data shows bright X-ray sources in this field, most of which are young
stars. In this image, red, green, and blue represent low, medium, and high energy
X-rays. The Chandra data have been overlaid on the Hubble Space Telescope image
to show the context of these X-ray data.
Very few X-ray sources are found in the pillars themselves. This suggests that the
Eagle Nebula may be past its star-forming prime, since young stars are usually
bright X-ray sources. However, there are two X-ray objects found near the tips of
the pillars. One is a young star about 4 or 5 times as massive as the Sun, visible as
the blue source near the tip of the pillar on the left. The other is a lower mass star
near the top of the other pillar that is so faint it is not visible in the composite
image.
M16 – xray stars
Star Formation
• Accompanied by dust!
• And some very powerful stars that are very
high temperature – emitting lots of light at Xray and UV
Red Giant
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BP Psc is a star like our Sun, but one that is more evolved, about 1,000 light years away.
New evidence from Chandra supports the case that BP Psc is not a very young star as
previously thought.
Rather, BP has spent its nuclear fuel and expanded into its "red giant" phase – likely
consuming a star or planet in the process.
Studying this type of stellar "cannibalism" may help astronomers better understand how stars
and planets interact as they age.
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The composite image on the left shows X-ray and optical data for BP Piscium (BP Psc), a more
evolved version of our Sun about 1,000 light years from Earth. Chandra X-ray Observatory
data are colored in purple, and optical data from the 3-meter Shane telescope at Lick
Observatory are shown in orange, green and blue. BP Psc is surrounded by a dusty and
gaseous disk and has a pair of jets several light years long blasting out of the system. A closeup view is shown by the artist's impression on the right. For clarity a narrow jet is shown, but
the actual jet is probably much wider, extending across the inner regions of the disk. Because
of the dusty disk, the star's surface is obscured in optical and near-infrared light. Therefore,
the Chandra observation is the first detection of this star in any wavelength.
BPPSC – Red Giant
Planetary Nebula
White Dwarf
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An international team of astronomers, studying the left-over remnants of stars like
our own Sun, have found a remarkable object where the nuclear reactor that once
powered it has only just shut down. This star, the hottest known white dwarf,
H1504+65, seems to have been stripped of its entire outer regions during its death
throes leaving behind the core that formed its power plant.
The Chandra X-ray data also reveal the signatures of neon, an expected by-product
of helium fusion. However, a big surprise was the presence of magnesium in
similar quantities. This result may provide a key to the unique composition of
H1504+65 and validate theoretical predictions that, if massive enough, some stars
can extend their lives by tapping yet another energy source: the fusion of carbon
into magnesium. However, as magnesium can also be produced by helium fusion,
proof of the theory is not yet ironclad. The final link in the puzzle would be the
detection of sodium, which will require data from yet another observatory: the
Hubble Space Telescope. The team has already been awarded time on the Hubble
Space Telescope to search for sodium in H1504+65 next year, and will, hopefully,
discover the final answer as to the origin of this unique star.
Artist impression
Supergiant to Supernova
Star Death
• A composite image from NASA's Chandra (blue) and Spitzer (green and
red-yellow) space telescopes shows the dusty remains of a collapsed star,
a supernova remnant called G54.1+0.3. The white source at the center is a
dead star called a pulsar, generating a wind of high-energy particles seen
by Chandra in blue. The wind expands into the surrounding environment.
The infrared shell that surrounds the pulsar wind, seen in red, is made up
of gas and dust that condensed out of debris from the supernova
explosion. A nearby cluster of stars is being engulfed by the dust.
• The nature and quantity of dust produced in supernova explosions is a
long-standing mystery, and G54.1+0.3 supplies an important piece to the
puzzle.
G54.1+0.3 Pulsar with wind
Neutron Star
• This composite image uses data from three of NASA's Great
Observatories. The Chandra X-ray image is shown in blue, the
Hubble Space Telescope optical image is in red and yellow,
and the Spitzer Space Telescope's infrared image is in purple.
The X-ray image is smaller than the others because extremely
energetic electrons emitting X-rays radiate away their energy
more quickly than the lower-energy electrons emitting optical
and infrared light. Along with many other telescopes, Chandra
has repeatedly observed the Crab Nebula over the course of
the mission's lifetime. The Crab Nebula is one of the most
studied objects in the sky, truly making it a cosmic icon.
Crab
Black Holes
• http://hubblesite.org/explore_astronomy/blac
k_holes/
Black Hole
• G1915
+105.
14
solar
masse
s.
Fe In BH
• Using Chandra spectra obtained from more
than 300 supermassive black holes in the
centers of galaxies, a team of astronomers has
been able to determine the amount of iron
near the black holes (light blue in illustration
on the right). The black holes were all located
in the North and South Chandra Deep Fields,
where the faintest and most-distant X-ray
objects can be identified.
Patterns and coincidences
• Along with physical models of gravity, gas
pressure, electrostatic repulsion, nuclear
physics
• Plus some nice spectral line measurements
• Get a beautiful scenario of stellar evolution
• Imagine the Universe powerpoint
Pretty Picture Finder
• http://www.nasaimages.org/
http://heritage.stsci.edu/
http://www.spitzer.caltech.edu
HR diagram & Stellar
Evolution
• Review where main sequence stars, super
giants, and white dwarfs are on HR diagram
Sharing
• GEARS wiki: gears-astro.wikispaces.com
• If you would like, we can give you permission
to edit!
Images
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Learn digital image basics and false color meaning
Learn a new software
Duplicate a press release
Identify some elements in some supernova
Make your color supernova image
Compare your color image to the press release!
Get data from other observations
Digital Image Basics
• More pixels good?
• What is false color?
• Why do we need false color?
Ds9
• First open image and play with software
• File: Open (you can’t open the files by double
clicking on them)
– Navigate to “My Computer”
– Navigate to “E:” (or the name of your thumb
drive)
– Navigate to GEARS workshop software
– Navigate to Data
– Look for file
ds9
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Make a press release
Get an X-ray image of galaxy cluster in sky
Get the same part of sky in visible light
Match up the coordinates so the 2 images are
lined up
• Try to match color scheme of press release
Supernova instructions
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Open ds9
Open chandraed virtual observatory
Open image assigned. (115 or 126)
Make a spectrum
Identify 3-5 strong lines using database
summarize the two types
Do if time/interest
• Make 3 energy cuts – or filters
• Make 3 color image
• Compare your result to the press release (look
for 2007 or later) energy cuts and color
choices
Spectral Line ID in X-ray
• http://www.atomdb.org
• Web Guide
• Check your units carefully
Complexities in Real Data
• Roman numeral notation = ionization notation we
teach minus 1
• Which element/transition is it?
– How do we know if it is Sulfur versus Fe XX?
– Verification with other lines is best
– Most abundant in universe is indicated in chart
• Do I use the EXACT wavelength?
– What is the material is moving towards or away from us?
May be Doppler Shifted
Supernova Remnants
• G292.0+1.8 & Tycho (left) – Saw from spectra
that they weren’t the same type of object
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Low Mass vs High Mass
Progenitor
High Mass
Tycho – Type Ia
• http://hubblesite.org/newscenter/archive/rel
eases/2004/34/
Core Collapse (on right)
Spectral Line ID in X-ray
• http://www.atomdb.org
• Need to remember/know that Fe XX means
Fe+19 (19 times ionized iron)
• HI = neutral hydrogen
• HII = singly ionized hydrogen
Different spectra
• Due to different progenitors – original stars
that exploded were composed of different
things
• In one – a white dwarf made of He or C with
material – primarily H – explodes
• In other – Fe and others smooshing into one
another
Differences
• Type Ia:
– Strong Si, S, Ar, Ca, Fe
– Weak O, Ne, Mg
• Type II – reverse
• Complications – the lines are not all alone – but there is a continuous
emission signature at all colors! (not blackbody though)
• Best way to deal with spectra is to account for the continuum using a
model – see http://chandra.harvard.edu/edu/formal/ X-ray Spectroscopy
and Supernova Remnants lab online.
Research your students can
do!
• http://cmarchesin.blogspot.com/2009/12/g29
2018-keplers-supernova-remnant.html
• Study with Chandra data – comparing shapes
of remnants – Type Ia – symmetric, Type II not
• This study was on only 17 objects – your
students could do more and see if trend holds
• How define symmetric?? Could be a
discussion all by itself.
How to get data
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By Obs ID from list
You saw obsid’s in press release images
If Obs ID is not in list – you can still get the image – go to middle area where there
is text and use search feature there.
Suppose the universe contained only low-mass stars.
Would elements heavier than carbon exist?
a. Yes, all stars create heavier elements than carbon when they
become a supernova.
b. Yes, but there would be far fewer heavier elements because
high-mass stars form elements like iron far more prolifically
than low-mass stars.
c. No, the core temperatures of low-mass stars are too low to
fuse other nuclei to carbon, so it would be the heaviest
element.
d. No, heavy elements created at the cores of low-mass stars
would be locked away for billions of years.
e. No, fission reactions would break down all elements heavier
than carbon.
Atmospheric Transparency
• Lab – there is a student worksheet for this –
but no instructions
Lab Instructions
• Find out what materials allow light to pass
through and be detected
• Note whether the material was a shield or a
transmitter
• See the power point for stations
Why do you need telescopes
in space?
• Brainstorm – and share your ideas and
• Metacognate – why you think what you think.
Is it distance?
Is it distance?
Example assessment
• Which of the two proposals would you choose to
fund?
• Project Rho: A UV wavelength telescope, placed high
atop Mauna Kea at 14,000 ft above sea level, which
will be used to look at distant galaxies?
• Project Sigma: A visible wavelength telescope, place
on a satellite in orbit around Earth, which will used to
observe a pair of binary stars located in the
constellation Ursa Major?
• Can you do the UV project effectively from
ground? Why or why not?
• Is it cost effective to do visible astronomy from
space? Especially for simple stellar
observations.
• Why send satellites in space to do visible
observations?