GEARS Workshop WednesdayDon’t forget there are hidden

slides and notes – don’t just use the show2011

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• 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/

features/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• 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• 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 X-ray and UV

Red Giant• 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.•

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 close-up 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• 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/

black_holes/

Black Hole• G1915

+105. 14 solar masses.

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• 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• 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• 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

Low Mass vs High Mass Progenitor

•

High Mass

Tycho – Type Ia• http://hubblesite.org/newscenter/archive/

releases/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/g292018-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• 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?