Download June 2013 Kepler Space Telescope Update

COMING EVENTS
POST SUMMER-CITY-BAND
CONCERT SCHEDULE
Volume 39 Number 06
Report from the Officers:
With the summer upon us, the primary events
for the club, observing-wise, will center on the
observing sessions after the City Band Concerts in South Park. The Band Concerts are
every Wed. evening starting at 8PM. They are
normally over around 9 PM, so telescope setup
should commence around 8:45 PM. Note - it
doesn’t get dark until after 9PM, usually by
9:30, but it pays to have the scopes set up as
dusk occurs so that people are drawn to the site
by the presence of the club and the equipment.
The setup site is in South Park on the side
WEST of Mass. St., usually in the open area at
June 12
June 26
July 10
South Park - West of Mass St.
SETUP ~ 8:45 PM
President
Rick Heschmeyer
[email protected]
Webmaster
Howard Edin
June 2013
the north end of the park.
[email protected]
Rick will communicate with club members via email to keep you aware of whether or
Observing Clubs
Doug Fay
[email protected]
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Kepler Space Telescope Update
ALCOR
William Winkler
[email protected]
One of the more successful space missions of all time has recently experienced what may be a critical failure which will effectively end long-term data
collection. The Kepler Space Telescope has been the focus of a number of
talks at AAL meetings over the last few years, emphasizing the exceptional
technology and data analysis for discovering and identifying potential
exoplanets using transits. Below is an update from late May laying out the
latest on the status of the scope and future prospects.
University Advisor
Dr. Bruce Twarog
[email protected]
INSIDE THIS ISSUE
Kepler Update (continued)
2
Infrared Iris
3
NASA Space Place
4
Polluted Stars
5
Ring of Fire
6
Red and Dead
7
The One True Ring
8
Polluted Stars (continued)
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Red and Dead (continued)
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Ring (continued)
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Kepler Mission Manager Update
Following the apparent failure of reaction wheel 4 on May 11, 2013, engineers were successful at transitioning the spacecraft from a ThrusterControlled Safe Mode to Point Rest State at approximately 3:30 p.m. PDT on
Wednesday, May 15, 2013. The spacecraft has remained safe and stable in
this attitude and is no longer considered to be in a critical situation.
As part of a normal spacecraft response to a pointing error, redundant electronics were automatically powered off to isolate them as a possible cause.
However, once the team recovered the spacecraft to Point Rest State (PRS)
and exonerated those systems, they were turned back on, providing full redundancy to the spacecraft. The reaction wheels remain offline. The photometer, which was turned off to reduce the power load, will be turned back
on in the near future to keep thermal conditions of the spacecraft within
nominal operating parameters. Kepler is not in science data collection.
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not the observing is on. Unfortunately, our first attempt to observe was rained out and the Band Concert was moved indoors.
It is likely that, at some point, the current series of rain storms will switch to our usual drought conditions for the summer, but
we will keep on trying and hope for the best - clear skies and not too hot!
Our last event in May was the presentation of the film Hayabusa at the Computer Center auditorium. Many thanks to Craig Paul of KU IT and his wife for making this opportunity available to the
club. The film was quite entertaining and nicely developed the history of the mission and its trials
and tribulations as seen through the eyes of a young female scientist struggling to complete a PhD
thesis while working on the mission as a supposed side project. It was an inspiring story from a variety of aspects, including the struggle to do basic research with inadequate funding support.
An upcoming event next month is the national convention of the Astronomical League, which
takes place from July 24 – 27, 2013 in Atlanta. If you have any interest in attending, the
web site for the meeting is http://alcon2013.astroleague.org/.
Any suggestions for improving the club or the newsletter are always welcome.
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PRS was developed in order to preserve fuel for an eventual recovery effort once a second wheel failed. This state
uses thrusters to control the pointing of the spacecraft, tipping it towards the sun and letting the solar pressure tip it
back away, resembling the motion of a pendulum. This is a very fuel-efficient mode, and it also provides an ondemand telemetry link to allow engineers to monitor and command the spacecraft. With nearly a week of PRS operations, the fuel usage appears to be on the low end of our estimates, allowing time for recovery planning.
The operations staff at Ball Aerospace did a wonderful job at developing and implementing PRS. As a result, the
spacecraft is not in an emergency condition, and work can be conducted at a more deliberate pace. For the next
week or so, we will contact the spacecraft on a daily basis to ensure PRS continues to operate as expected.
Over the coming weeks, an anomaly response team (ART) will evaluate wheel recovery options. The ART includes
members from NASA Ames, Ball Aerospace, the Jet Propulsion Laboratory and UTC, the wheel manufacturer. This
team has access to a broader reach of experts throughout NASA and industry, and will manage the wheel recovery
efforts.
The team will continue to analyze recent telemetry received from the spacecraft. This analysis, and any planned
recovery actions, will take time, and will likely be on the order of weeks, possibly months. Any planned commanding
will first be vetted on the spacecraft test bed to validate command operability.
For now, PRS is working very well and keeping Kepler safe. We will provide updates on significant changes as the
plan develops.
We are grateful to all our followers for their well wishes and support!
Regards,
Roger
About the Astronomy Associates of Lawrence
The club is open to all people interested in sharing their love for astronomy. Monthly meetings are typically on the second Friday of each month and often feature guest speakers, presentations by club members, and a chance to exchange amateur astronomy tips. Approximately the last Sunday of each month we have an open house at the Prairie Park Nature Center. Periodic
star parties are scheduled as well. For more information, please contact the club officers: president, Rick Heschmeyer at
[email protected]; webmaster, Howard Edin, at [email protected]; AlCor William Winkler, at
[email protected]; or faculty advisor, Prof. Bruce Twarog at [email protected]. Because of the flexibility of the schedule
due to holidays and alternate events, it is always best to check the Web site for the exact Fridays and Sundays when events
are scheduled. The information about AAL can be found at
http://groups.ku.edu/~astronomy
Copies of the Celestial Mechanic can also be found on the web at
http://groups.ku.edu/~astronomy/celestialmechanic
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Infrared Iris
This cloud of glowing gas is the Iris nebula, as seen in infrared light by NASA's Spitzer Space Telescope. The
main cluster of stars within the nebula is called NGC 7023. It lies 1,300 light-years away in the Cepheus constellation.
Between 2003 and 2005, thanks to its unprecedented sensitivity, NASAs Spitzer Space Telescope created maps
of regions like this, showing the location of complex organic molecules called polycyclic aromatic hydrocarbons
(PAHs). PAHs may be precursors to the organic ingredients that kick started life on Earth.
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Triple Treat
By Dr. Ethan Siegel
(Editor’s note: The event discussed below
wasn’t visible from Lawrence due to cloud
cover on the day of interest but it was felt that you might want to see what you missed.)
The solar system is a busy place, with five wandering planets visible to the naked eye alone. When any two pass close by
each other from our point of view, we see an astronomical conjunction, but on very rare occasions, three planets will find
themselves grouped together: a triple conjunction. Towards the end of May, Mercury, Venus and Jupiter will treat us to the
best triple conjunction in years.
On May 25th, Mercury will pass within 1.4° of Venus, then two days later Mercury comes within 2.4° of Jupiter, and finally
on the 28th, Jupiter and Venus approach within 1° of one another. If it weren’t for the slight orbital tilt of our solar system’s
planetary orbits, these conjunctions would all be occultations instead. During the nights of May 26th-27th, all three planets
are visible immediately
after sunset within the
same 3° field of view,
with the triple conjunction peaking in a triangular shape on the
26th. (For scale, the full
Moon subtends about
1/2°.) The three planets
appear close together
for a few days more,
making a line in the sky
on the 30th/31st.
How does this happen?
Mercury and Venus
race around the Sun far
faster than Earth, with
Mercury completing
more than four revolutions around the Sun for
each one that Earth
makes. At the same
The image shows the configuration of Mercury, Venus, and Jupiter in the western sky just after
time, Jupiter is far
sunset on May 26, 2013. Insets show the relative size appearance of the planets on that date.
slower, taking 12 years
to orbit just once around
the Sun. Jupiter’s been high in the sky during the early parts of the night, but steadily lowers throughout May as Earth continues to move away from it, approaching its maximum distance from Earth. Mercury and Venus, meanwhile, begin to
move out from behind the Sun during May: Venus at the beginning of the month and Mercury in the middle.
Thus, during this triple conjunction, all three planets will be on the far side of the Sun, something that happens just 25% of
the time in triple conjunctions involving Mercury and Venus! If you telescopically resolve these planets into disks, you’ll see
our inner worlds in a nearly-full gibbous phase. Jupiter will appear largest in terms of angular diameter, followed by Venus
and lastly by Mercury. Just a year ago, during its now-famous transit, Venus took up more than a full arc-minute in the sky;
during this conjunction, it will just one-sixth that angular size and less than a third the apparent diameter of Jupiter. Nevertheless, Venus will still be more than six times as bright as Jupiter during this time, outshining all night-sky objects other
than the Moon. Closer conjunctions of two naked-eye planets are frequent, but getting three or more like this happens just
once or twice per decade, so don’t miss your chance to see it.
And speaking of occultations, The Space Place has a great kid-friendly explanation of the Venus transit and solar eclipses
of 2012 at spaceplace.nasa.gov/venus-transit. Dr. Ethan Siegel, a theoretical astrophysicist, is a professor at the University of Portland (OR) and Lewis & Clark College.
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Hubble Finds Dead Stars 'Polluted' with Planet Debris
NASA's Hubble Space Telescope has found the building blocks for Earth-sized planets in an unlikely place, the
atmospheres of a pair of burned-out stars called white dwarfs. The dwarfs are being polluted by asteroid-like debris
falling onto them. This discovery suggests that rocky planet assembly is common in stars, say researchers.
The white dwarfs reside 150 light-years away in the Hyades star cluster, residing in the constellation Taurus the
Bull. The cluster is relatively young, only 625 million years old.
Hubble's spectroscopic observations identified silicon in the white dwarfs' atmospheres, a major ingredient of the
rocky material constituting Earth and other terrestrial planets in our solar system. The silicon may have come from
asteroids that were shredded by the white dwarfs' gravity when they veered too close to the stars. The rocky debris
likely formed a ring around the dead stars, which then funneled the material onto the stellar relics.
The material detected
whirling around the
white dwarfs suggests
that terrestrial planets
formed when these
stars were born. After
the stars collapsed to
white dwarfs, surviving
gas-giant planets may
have gravitationally
perturbed members of
any leftover asteroid
belts into star-grazing
orbits.
"We have identified
chemical evidence for
the Lego building
blocks of rocky planets," says Jay Farihi of
the University of Cambridge in England, lead
author of a new study
that appeared in the
May 2 issue of the
Monthly Notices of the
Royal Astronomical Society. "When these stars were born, they built planets, and there's a good chance they currently retain some of them. The material we are seeing is evidence of this. The debris is at least as rocky as the
most primitive terrestrial bodies in our solar system."
Astronomers commonly believe that all stars formed in clusters. But searches for planets outside our solar system
have only detected a handful of them orbiting cluster stars. Farihi suggested that it may be harder to make the precision measurements needed to find extrasolar planets in clusters because the stars are young and more active,
producing stellar flares and other outbursts.
The team, therefore, searched planets around retired cluster stars. "Using Hubble to analyze the atmospheres of
white dwarfs is the best method for finding the signatures of solid planet chemistry and determining their composition," Farihi explains. "Normally, white dwarfs are like blank pieces of paper, containing only the light elements hydrogen and helium. Heavy elements like silicon and carbon sink to the core."
Besides finding silicon in the Hyades stars' atmospheres, Hubble also detected low levels of carbon, another sign of
the debris' rocky nature. Astronomers would expect carbon to be depleted or absent in rocky, Earth-like material.
Carbon is a key element that helps astronomers determine the properties and origin of the planetary debris raining
down onto white dwarfs. It leaves fingerprints only in ultraviolet light, which cannot be observed from ground-based
telescopes. Finding its chemical signature required Hubble's Cosmic Origins Spectrograph (COS).
"The one thing the white dwarf pollution technique gives us that we just won't get with any other planet-detection
technique is the chemistry of solid planets," Farihi says. "Based on the silicon-to-carbon ratio in our study, for example, we can actually say that this material is basically Earth-like. If you put this stuff into the hand of a child, or an
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Galaxy's Ring of Fire
Spitzer Space Telescope Press Release
Johnny Cash may have preferred this galaxy's burning ring of fire to the one he sang about falling into in his popular
song. The "starburst ring" seen at center in red and yellow hues is not the product of love, as in the song, but is
instead a frenetic region of star formation.
The galaxy, a spiral beauty called Messier 94, is located about 17 million light-years away. In this image from
NASA's Spitzer Space Telescope, infrared light is represented in different colors, with blue having the shortest
wavelengths and red, the longest.
Starburst rings like this can often be triggered by gravitational encounters with other galaxies but, in this case, may
have instead been caused by the galaxy's oval shape. Gas in the ring is being converted into hot, young stars,
which then warm the dust, causing it to glow with infrared light.
The outer, faint blue ring around the galaxy might be an optical illusion. Astronomers think that two separate spiral
arms appear as a single unbroken ring when viewed from our position in space.
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Rare Merger Illuminates Origin of Read and Dead Galaxies
Most massive galaxies in the Universe fall into two major categories: gas-rich spirals that are actively forming stars, and
gas-poor ellipticals, populated by old, red stars and with little or no ongoing star formation. Astronomers have been investigating for decades how these two different types of galaxies came into being and whether spirals may be the progenitors
of ellipticals via galactic mergers.
A puzzling discovery made in the past decade was that of 'red and dead' galaxies in the young Universe: very massive
and passive ellipticals found at redshifts between 2 and 1.5, corresponding to epochs in cosmic history when the Universe
was three to almost five billion years old, or only about one third of its present age. Somehow, on a short cosmological
timescale, these galaxies managed to exhaust
their gas reservoir and
consequently stopped
forming stars: this left
them with stellar populations that had already
aged enough to appear
red and old.
A new study based on
data from ESA's
Herschel Space Observatory has discovered a
rare snapshot of when
two massive, gas-rich
and actively starforming galaxies were
merging into an extremely massive elliptical galaxy. The result,
published in the journal
Nature, suggests that a
merger between gasrich galaxies is an efA pair of merging galaxies in the young Universe discovered with Herschel (left panel) and imfective mechanism to
aged at higher resolution at near-infrared, sub-millimetre and radio wavelengths (right panel).
form the most massive
Credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO
elliptical galaxies
known, even when the
Universe was quite young. "This system of interacting galaxies is truly exceptional," comments Hai Fu from University of
California, Irvine, USA, who led the study. "It's unusual not only due to the high mass and intense star-forming activity of
the two galaxies involved, but also because it exposes a crucial, intermediate step of the formation process. Such starbursting galaxies have very short lifetimes – in cosmological terms – so seeing a pair 'in action' is extremely rare and valuable to constrain models for the formation and evolution of galaxies." The source, named HXMM01, was originally detected as an unusually bright object in the HerMES project, a large survey compiled with Herschel aimed at investigating
galactic evolution in the distant Universe. With a redshift of about 2.3, HXMM01 dates back to the epoch when the Universe was barely three billion years old.
"We were concerned that HXMM01's intense brightness at sub-millimetre wavelengths might be due to gravitational lensing – the bending of light caused by foreground massive objects. In some cases, that can strongly magnify the appearance of a background galaxy," explains co-author Asantha Cooray, also from University of California, Irvine, USA. Previous studies based on Herschel data have revealed a handful of high-redshift galaxies whose flux is greatly amplified via
gravitational lensing. In those cases, the boosting effect made the detection easier for the astronomers.
"But we discovered that gravitational lensing is not the reason for HXMM01's extreme brightness. The source really is very
bright because it consists of two intrinsically bright galaxies in the process of merging," says Cooray. The astronomers
conducted extensive follow-up observations across the electromagnetic spectrum, from radio and sub-millimetre wavelengths to the near-infrared and optical domain. These data provided a higher resolution view of HXMM01, revealing two
separate sources, which are two physically distinct galaxies lying at redshift 2.310 and 2.307 respectively.
By proving that the two sources are at slightly different distances from us, the astronomers were certain that strong gravitational lensing was not affecting their findings either through causing multiple images, or excessively boosting the flux of
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NASA'S HUBBLE SPACE TELESCOPE REVEALS THE RING NEBULA'S TRUE SHAPE
The Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's
Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C.
Robert O'Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several groundbased telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula. "With Hubble's detail, we see a completely different shape than what's been thought about historically for this classic nebula," O'Dell said.
"The new Hubble observations show the nebula in much clearer detail, and we see things are not as simple as we previously thought."
The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers. Previous observations by several telescopes had detected the gaseous material in the ring's central region. But the new view by Hubble's sharp-eyed Wide Field Camera 3
shows the nebula's structure in more detail. O'Dell's team suggests the ring wraps around a blue, football-shaped structure.
Each end of the structure protrudes out of opposite sides of the ring.
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adult, and you ask them, `What is this?' Any human being would be able to respond, ‘It's a rock!' They wouldn't need to
be a scientist. They would know exactly what it is, as it's something familiar to all of us."
Farihi suggests that asteroids less than 100 miles (160 kilometers) across were probably gravitationally torn apart by
the white dwarfs' strong tidal forces. The pulverized material may have been pulled into a ring that eventually fell onto
the dead stars. "It's difficult to imagine another mechanism than gravity that causes material to get close enough to rain
down onto the star," he says.
The team estimated each asteroid's size by measuring the amount of dust being gobbled up by the dead stars, about
10 million grams per second, equal to the flow rate of a small river. They then compared that data with measurements
of material falling onto other white dwarfs. The Hyades study offers insight into what will happen in our solar system
when our Sun burns out 5 billion years from now. When the Sun exhausts its hydrogen fuel, it will puff up to a red giant
and swallow Mercury and Venus, and perhaps the Earth. As the Sun begins to eject its outer layers, it loses mass. The
balance of gravitational forces between the Sun and Jupiter changes, disrupting the main asteroid belt. Some of these
asteroids could veer too close to the Sun, which breaks them up. The debris could be pulled into a ring around the
dead Sun, similar to the inferred rings around the Hyades white dwarfs.
The two "polluted" Hyades white dwarfs are part of the team's search of planetary debris around more than 100 white
dwarfs, led by Boris Gänsicke of the University of Warwick in England. Team member Detlev Koester of the University
of Kiel in Germany is using sophisticated computer models of white dwarf atmospheres to determine the abundances
of various elements that can be traced to planets in the COS data. The team plans to analyze more white dwarfs using
the same technique to identify not only the rocks' composition but also their parent bodies. "The beauty of this technique is that whatever the universe is doing, we'll be able to measure it," Farihi said. "We have been using our solar
system as a kind of map, but I don't know what the universe does. Is there another recipe for Earth-like or habitable
planets? The chemistry can tell us. Hopefully, with Hubble and its powerful ultraviolet-light camera COS, and with the
upcoming ground-based 30- and 40-meter telescopes, we'll be able to tell a story. We hope to create a picture of hundreds of rocky planet building blocks and tell how often they look like Earth and how often they look different, or even
exotic. Who knows, maybe we'll find some stuff we haven't thought of yet."
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the source. Two foreground galaxies, at redshifts of 0.502 and 0.655, were also detected in the same field, but they
only exert weak gravitational lensing on the merging system in the background.
"We estimate that the two galaxies are about 65,000 light years apart, which is a typical separation for pairs of interacting galaxies," explains Fu. "We also see a bridge of gas connecting the two galaxies in the radio data, which is comparable with similar features that we see in merging galaxies in the local Universe." Each of the two galaxies has a stellar
mass of about 100 billion solar masses, and they each contain roughly the same amount of gas. The astronomers estimated that the merging process would take at most 200 million years to complete, resulting in a massive elliptical galaxy of about 400 billion solar masses.
"We see these two galaxies forming stars at a phenomenal rate – about 2000 stars like the Sun per year – and the
conversion of gas into stars is more efficient than in normal galaxies by an order of magnitude," says Fu.
Such a high star-formation rate, spurred by the merger process itself, is not sustainable and would not take long to exhaust the gas reservoir of both progenitor galaxies and quench star formation. The astronomers believe that such a
merger must have produced a descendant galaxy with passive star-forming activity and a stellar population of old and
red stars.
"We were very lucky to catch this extreme system in such a critical transitional phase. It shows that the merger of gasrich and actively star forming galaxies is a possible mechanism to form the most massive ellipticals that are observed in
the young Universe," comments Seb Oliver from University of Sussex, UK, and Principal Investigator of the HerMES
Key Programme, within which the data have been collected.
There are expected to be similar systems of interacting galaxies at comparable redshifts distributed sparsely across the
sky – about one every 100 square degrees. It is possible that a few more will be found in the examination of Herschel
data, but the likelihood of finding galaxies on the brink of merging, as in this case, is not very high.
"This discovery highlights the importance of the vast surveys that were completed with Herschel," comments Göran
Pilbratt, Herschel Project Scientist at ESA. "Scanning large portions of the sky is crucial to finding exceptional sources
like HXMM01, which may provide the solution to the riddle of how very massive elliptical galaxies could form when the
Universe was still young."
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The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of
helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf
is the stellar remnant of a sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally
collapse to a compact object. O'Dell's team was surprised at the detailed Hubble views of the dark, irregular knots of dense gas
embedded along the inner rim of the ring, which look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the
wave of ultraviolet light unleashed by the star. The Hubble images have allowed the team to match up the knots with the spikes
of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.
All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our
sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size,
becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.The outer rings were
formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an
hour, but the center is moving faster than the expansion of the main ring. O'Dell's team measured the nebula's expansion by
comparing the new Hubble observations with Hubble studies made in 1998.
The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium. Studying the Ring Nebula's fate will provide insight into the
sun's demise in another 6 billion years. The sun is less massive than the Ring Nebula's progenitor star, so it will not have an opulent ending.
"When the sun becomes a white dwarf, it will heat more slowly after it ejects its outer gaseous layers," O'Dell said. "The material
will be farther away once it becomes hot enough to illuminate the gas. This larger distance means the sun's nebula will be fainter
because it is more extended." In the analysis, the research team also obtained images from the Large Binocular Telescope at
the Mount Graham International Observatory in Arizona and spectroscopic data from the San Pedro Martir Observatory in Baja
California, Mexico.
AAL
Celestial Mechanic June 2013
Astronomy Associates of
Lawrence
University of Kansas
Malott Hall
1251 Wescoe Hall Dr, Room 1082
Lawrence, KS 66045-7582
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