Download OverviewJuly2007 - Magdalena Ridge Observatory

Overview of the MRO 2.4m Telescope
Dr. Eileen V. Ryan
2.4m Telescope Project Manager/Project Scientist
(NM Tech/Magdalena Ridge Observatory)
July 11, 2007
The 2.4-meter Project:
The 2.4 meter telescope has three basic objectives:
July 11, 2007
•
Classical astronomical research, with
queue & remote observing (e.g.,
small bodies, transient phenomena).
•
DoD mission support: missile
tracking, satellite signatures, sensor
development. (The telescope will be
fast-tracking).
•
Support & enhance NM education &
public outreach.
Focus Area:
The MRO 2.4-meter is one of the
largest telescopes in the world
that has as its primary mission
the study of small bodies (both
natural and artificial) in the
Solar System.
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Dedication Ceremony: October 26, 2006
July 11, 2007
Image of Saturn
taken with the 2.4m
telescope.
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April 2007 Public Events:
Belen Middle School
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Telescope Operations:
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Asteroid Belt
• Collisions are a fundamental
process in the solar system &
are not yet well understood.
• Applications: planetary
accretion, evolution of ring
systems, evolution of the
asteroid and Kuiper belts,
planetary cratering, meteorite
ejection and delivery, etc.
• Also: Earth-Crossers (NEAs)
are a potential hazard-Congressional metric issued.
Locations of asteroids: April 8, 2003
July 11, 2007
Asteroids: Characteristics
• Size Range: Power-law
distribution from a few large
(1000 km Ceres, 500 km Vesta)
to many kilometer and metersized bodies.
• Shapes: Most are highly
irregular/ellipsoidal
• Composition: Silicates, Irons,
Stoney-irons
July 11, 2007
NEA Eros
NEA Itokawa
• Size: 300 meters
• Density: 1.9 g/cm3 (Packed
more loosely than sand).
• Gravity is so low (Vesc
=10 cm/s), if you “shook”
it gently, the pieces would
fly apart.
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Impact Craters on Earth (~160)
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Meteorite Impacts on Earth
Leonid Meteor Shower
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Impacts on the Earth
Geologic & atmospheric weathering have covered the
evidence of most impacts, but...
• The Earth DOES get hit by asteroid fragments (meteorites) all the time
(the atmosphere protects us from objects up to ~50 meters in diameter).
• Objects >50 m but < 1 km would reach the Earth's surface and cause
only local damage; Objects > 1 km are global killers!
Chicxulub Crater
180 km diameter
(65 million years ago)
July 11, 2007
Meteor Crater
1.6 km diameter
(50,000 years ago)
50 km Tunguska Airburst
50 km flattened area
(95 years ago)
Asteroid Hazards Issues:
• Greatest risk: Objects large enough
to perturb the Earth's climate on a
global scale
• How? Injecting large quantities of
dust into the stratosphere
• Result: Temperatures decrease around the globe,
leading to massive loss of food crops
• Threshold Diameter: 1 - 2 km (Explosion equivalent to
a million megatons of TNT– Hiroshima was 17 kilotons.)
July 11, 2007
Dealing with the Risks:
For High-Explosive Mitigation of asteroid hazards:
Need to derive the energy to fragment &
disperse the object, which is dependent on:
• Composition
• Internal Structure (intact vs. porous)
• Size
July 11, 2007
Complication: Asteroid Porosity
For High-Explosive Mitigation of asteroid hazards:
Numerical simulations & laboratory studies indicate that
more energy may be required to fragment porous bodies!
And there is a “range” in porosities observed.
July 11, 2007
Deep Impact Space Mission
Crater size can reveal porosity & strength.
In July of 2005, the Deep
Impact spacecraft released a
370 kg impactor directly
into the path of comet
Tempel 1 (~14 km in size) at
a speed of ~10.2 km/sec. The
resulting collision produced
an impact crater on the
surface about 100 meters in
diameter.
NEO Comet Temple 1
July 11, 2007
ESA Don Quijote Mission
Impactor: Hidalgo
Orbiter: Sancho
ESA's Don Quijote is an asteroid deflection precursor
mission, designed to assess and validate the technology that
one day could be used to deflect or destroy an asteroid
threatening the Earth.
July 11, 2007
Asteroid/Satellite Photometry
• Asteroids/satellites shine
from reflected sunlight–
proportional to crosssectional area at small solar
phase angles (0 is sun
behind observer).
• As the object rotates, the
amount of light varies.
• By measuring the light
variation over time, we
derive a rotation rate and
constrain orientation &
shape.
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Asteroid Ida
(Rotation Images, Galileo Spacecraft)
“Typical” Asteroid Lightcurve
NEO Asteroid Lick over a 3
hour time period (moves from
bottom center to upper left).
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Model Simulation
Asteroid Kleopatra
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Near-Earth Asteroid 2007 FK1
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Near-Earth Asteroid 2007 FK1
Discovered on March 17, 2007
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Near-Earth Asteroid 2007 FK1
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Near-Earth Asteroid 2007 FK1
• Orbital speed (relative
to Sun): ~36 km/s
• Speed (relative to
Earth): ~ 8 km/s
• Angular Speed
(relative to observer):
~7.5"/min on May 14
Distance from Earth= 0.08 AU
May 14, 2007
July 11, 2007
• Size based on an
absolute visible
magnitude H=20.1
150-470 meters.
Tracking NEA 2007 FK1
Tracking 2007 FK1 with the 2.4m Telescope on May 14, 2007
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Near-Earth Asteroid 2007 FK1
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Near-Earth Asteroid 2007 FK1
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Near-Earth Asteroid 2007 FK1
July 11, 2007
Find the Asteroid!
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Answer:
July 11, 2007
Near-Earth Comet Linear VZ 13
Tracking Comet Linear VZ 13 with the 2.4m Telescope on July 6, 2007
July 11, 2007
Lucky Imaging
Binary Star: Zeta Bootis (0.7" separation). Images taken with the
2.4m telescope on May 28, 2007.
Before
Conditions: 36 mph winds, 1.3 arcsec
seeing, thin clouds, 1 second exposures.
After
Selected Image Reconstruction: 13 best
of 1000 images taken with 0.001 second
exposures, aligned and averaged.
July 11, 2007
Radial plot
Lucky Imaging
Another Binary Star: Rotanev (0.6" separation). Images taken
with the 2.4m telescope on May 28, 2007.
Selected Image Reconstruction: 15 best of
1000 images taken with 0.001 second
exposures, aligned and averaged using the
MRO 2.4m telescope on May 28, 2007.
July 11, 2007
Rotanev Binary Star System:
Imaged at Starfire Optical Range
using Adaptive Optics.
Star Trails:
Photo by Mark Vincent
July 11, 2007