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Near Earth Objects NEOs

topic posted Wed, June 6, 2007 - 6:29 AM by  prometheusPAN
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From: prometheuspan (Original Message) Sent: 1/26/2006 5:06 PM
Near-Earth Objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth's neighborhood. Composed mostly of water ice with embedded dust particles, comets originally formed in the cold outer planetary system while most of the rocky asteroids formed in the warmer inner solar system between the orbits of Mars and Jupiter. The scientific interest in comets and asteroids is due largely to their status as the relatively unchanged remnant debris from the solar system formation process some 4.6 billion years ago. The giant outer planets (Jupiter, Saturn, Uranus, and Neptune) formed from an agglomeration of billions of comets and the left over bits and pieces from this formation process are the comets we see today. Likewise, today's asteroids are the bits and pieces left over from the initial agglomeration of the inner planets that include Mercury, Venus, Earth, and Mars.
As the primitive, leftover building blocks of the solar system formation process, comets and asteroids offer clues to the chemical mixture from which the planets formed some 4.6 billion years ago. If we wish to know the composition of the primordial mixture from which the planets formed, then we must determine the chemical constituents of the leftover debris from this formation process - the comets and asteroids.


In terms of orbital elements, NEOs are asteroids and comets with perihelion distance q less than 1.3 AU. Near-Earth Comets (NECs) are further restricted to include only short-period comets (i.e orbital period P less than 200 years). The vast majority of NEOs are asteroids, referred to as Near-Earth Asteroids (NEAs). NEAs are divided into groups (Aten, Apollo, Amor) according to their perihelion distance (q), aphelion distance (Q) and their semi-major axes (a).

Group Description Definition
NECs Near-Earth Comets q<1.3 AU, P<200 years
NEAs Near-Earth Asteroids q<1.3 AU
Atens Earth-crossing NEAs with semi-major axes smaller than Earth's (named after asteroid 2062 Aten). a<1.0 AU, Q>0.983 AU
Apollos Earth-crossing NEAs with semi-major axes larger than Earth's (named after asteroid 1862 Apollo). a>1.0 AU, q<1.017 AU
Amors Earth-approaching NEAs with orbits exterior to Earth's but interior to Mars' (named after asteroid 1221 Amor). a>1.0 AU, 1.017<q<1.3 AU
PHAs Potentially Hazardous Asteriods: NEAs whose Minimum Orbit Intersection Distance (MOID) with the Earth is 0.05 AU or less and whose absolute magnitude (H) is 22.0 or brighter. MOID<=0.05 AU, H<=22.0




WHAT IS A PHA?
Potentially Hazardous Asteroids (PHAs) are currently defined based on parameters that measure the asteroid's potential to make threatening close approaches to the Earth. Specifically, all asteroids with an Earth Minimum Orbit Intersection Distance (MOID) of 0.05 AU or less and an absolute magnitude (H) of 22.0 or less are considered PHAs. In other words, asteroids that can't get any closer to the Earth (i.e. MOID) than 0.05 AU (roughly 7,480,000 km or 4,650,000 mi) or are smaller than about 150 m (500 ft) in diameter (i.e. H = 22.0 with assumed albedo of 13%) are not considered PHAs.

There are currently 764 known PHAs.
This ``potential'' to make close Earth approaches does not mean a PHA will impact the Earth. It only means there is a possibility for such a threat. By monitoring these PHAs and updating their orbits as new observations become available, we can better predict the close-approach statistics and thus their Earth-impact threat.


The comets and asteroids that are potentially the most hazardous because they can closely approach the Earth are also the objects that could be most easily exploited for their raw materials. It is not presently cost effective to mine these minerals and then bring them back to Earth. However, these raw materials could be used in developing the space structures and in generating the rocket fuel that will be required to explore and colonize our solar system in the twenty-first century. It has been estimated that the mineral wealth resident in the belt of asteroids between the orbits of Mars and Jupiter would be equivalent to about 100 billion dollars for every person on Earth today. Whereas asteroids are rich in the mineral raw materials required to build structures in space, the comets are rich resources for the water and carbon-based molecules necessary to sustain life. In addition, an abundant supply of cometary water ice could provide copious quantities of liquid hydrogen and oxygen, the two primary ingredients in rocket fuel. It seems likely that in the next century when we begin to colonize the inner solar system, the metals and minerals found on asteroids will provide the raw materials for space structures and comets will become the watering holes and gas stations for interplanetary spacecraft.
Reference: Lewis, John S. Mining the Sky: Untold Riches from the Asteroid, Comets, and Planets. Addison-Wesley, 1996.


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Recommend Delete Message 2 of 5 in Discussion
From: prometheuspan Sent: 1/26/2006 5:32 PM
www.astro.uwo.ca/~wiegert/AA29/AA29.html

Earth coorbital asteroid 2002 AA29
Martin Connors
Centre for Science, Athabasca University, Athabasca AB CANADA


Paul Chodas
Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA USA

Seppo Mikkola
Tuorla Observatory, University of Turku FINLAND

Paul Wiegert
Dept. of Physics, The University of Western Ontario, London ON CANADA


Christian Veillet
Canada-France-Hawaii Telescope, Kamuela HI USA


Kimmo Innanen
Dept. of Physics and Astronomy, York University, Toronto ON CANADA







--------------------------------------------------------------------------------

Press release
September 2002
An international team of astronomers has found that an asteroid discovered earlier this year follows Earth's orbit around the Sun and will, in nearly 600 years, appear to orbit the Earth. In the October issue of the journal Meteoritics and Planetary Science, the astronomers announce that the asteroid, named 2002 AA29, follows a "horseshoe orbit" that makes it come near the Earth every 95 years. It will next come close on January 8, 2003, although even then it will be much further away than the Moon and only detectable using large telescopes. The combination of Earth's and Sun's gravity works so that even as Earth pulls in the asteroid, it speeds up and moves away from the Earth. In this way Earth is protected from impact, despite the similarity of the asteroid's orbit to Earth's.

The special horseshoe orbit was pointed out by Paul Chodas of the Jet Propulsion Laboratory in Pasadena to Martin Connors of Athabasca University in Canada, shortly after the object was discovered in January by the LINEAR asteroid survey. Connors, then on leave in California, alerted colleagues at Queen's University in Kingston, Ontario, York University in Toronto, and the Tuorla Observatory in Finland. Rapid calculations confirmed the special nature of the orbit, and followup observations were taken by Christian Veillet with the large Canada-France-Hawaii telescope. "Most of us had worked together to search for objects closely related to this one, so our team was ready to spring into action", states Connors. Besides finding that the object would come close to Earth next year and then move around Earth's orbit to come back in 2098, the team found that in about 600 years, the asteroid will become a "quasi-satellite" of the Earth. While Earth has only one natural satellite, the Moon, for about fifty years this small asteroid will move near the Earth and appear to be in orbit, going around once a year. In fact, explains team member Paul Wiegert of Queen's University, "both the Earth and the asteroid still both go around the Sun, but the relative looping motion of the asteroid in some ways resembles a satellite orbit, with an apparent period of one year". Calculations by Seppo Mikkola in Finland suggest that the asteroid has already been a quasi-satellite, from about 550 to 600 A.D., but since it is such a small object it would not have been seen then.

The vast majority of asteroids are in belt between the planets Mars and Jupiter, thus rather far from the Earth. Even near-Earth asteroids, that sometimes cause a panic when they fly by, usually have orbits reaching out to the asteroid belt. Coorbital asteroids similar in some ways to 2002 AA29 are known to follow Jupiter's orbit and Mars' orbit, but this is the first one known for Earth. Some asteroids are known to have a similar interplay with Earth's gravity, but do not follow our orbit as closely as does 2002 AA29. Wiegert, Mikkola, and Innanen found the first such object, called Cruithne, in the mid-1990s, but its orbit is very stretched out. The orbit of 2002 AA29 is very round like Earth's, but slightly tilted. An orbit similar to Earth's makes a body easy to reach with spacecraft. The scientists hope to use 2002 AA29 as an example showing that asteroids moving along Earth's orbit do exist, so that they can search for other asteroids with orbits even more similar to ours. Such asteroids could be good targets for space missions and could even be sources of raw materials in space. These special asteroids will likely be hard to find but fascinating. As team member Kimmo Innanen says, "Mother Nature keeps showing us that her repertoire is more bountiful than we thought!"


More on Earth Coorbital Asteroids
What we call "Earth coorbital asteroids" (or ECAs) here are asteroids in a 1:1 mean-motion resonance with the Earth. That means that they go around the Sun in the same amount of time as the Earth does, that is, one year. Though the Earth and the asteroids don't always move at the same speed at every instant, their average (or mean) motion is the same, hence the name 1:1 mean-motion resonance.

The best known cases of this resonance are the Trojan asteroids of Jupiter. Over 400 hundred asteroids remain stable either approximately 60 degrees ahead of or behind Jupiter as it goes around its orbit; both planet and asteroids take 11.86 years to circle the Sun. The Earth may also have similar bodies (Earth Lagrange point asteroids) though none are yet known.

Earth companion asteroids are bodies in 1:1 mean motion resonance, though are not necessarily confined ahead of or behind our planet the way Trojans are. Nonetheless, they are not just coincidentally in our vicinity in the way most Near-Earth asteroids are. ECAs share a specific though subtle kind of dynamical relationship with the Earth.

What makes asteroid 2002 AA29 especially interesting?
Asteroid 2002 AA29 was discovered by the LINEAR asteroid search program in January 2001. Shortly after this, the coorbital nature of the orbit of 2002 AA29 was pointed out by Martin Connors (Athabasca U) and Paul Chodas (JPL). A follow-up image, taken by Kyle Smalley with the 0.75 meter telescope at the Astronomical Society of Kansas City's Powell Observatory, is shown on the left. The image is composed of sequential exposures which were "stacked" so that asteroid is in the same spot in them all. Since the asteroid moves against the background stars from exposure to exposure, the stacking results in the stars getting smeared out into long tracks across the image. The bars indicate the position of the faint asteroid 2002 AA29. It was 0.065 AU (astronomical units, equal to the distance between the Earth and the Sun) or about 10 million km away from Earth when this was taken. Note: other faint dots on the image are not asteroids, but glitches due to cosmic rays hitting the detector. These can be differentiated from real objects by examining the image at higher resolution than seen here. To view the time-lapse path of 2002 AA29 gliding past distant galaxies, check out this animation of images taken by Christian Veillet at the Canada-France-Hawaii Telescope. 2002 AA29 is the fuzzy dot that can be seen drifting along against the background stars (the line it moves along was added in post-processing). The two brightest blobs are galaxies that happen to be in the same field of view. What looks like another asteroid passing through the upper left corner of some of the frames is not real, just a by-product of the way the frames were processed.

Most of the time, the path of asteroid 2002 AA29 looks as shown to the right. Note that we are looking at the asteroid from above the Sun, and in a frame which moves along with the Earth, which remains stationary at the bottom of the frame (for an animated view, see the MPEG movie clip).

When seen in this frame, the reason for the name "horseshoe orbit" becomes apparent. The asteroid loops along the Earth's orbit, but reverses direction when it approaches our planet from either side. This phenomena is a result of the 1:1 mean-motion resonance. Each loop takes one year to complete; and it takes 95 loops (years) for 2002 AA29 to go from one end of the horseshoe to the other. A fuller explanation of horseshoe orbits can be found on the 3753 Cruithne page.

However, for part of the time, 2002 AA29 goes into quasi-satellite mode. At this time, instead of avoiding the vicinity of the Earth, the asteroid's motion is restricted there. Instead of covering the whole horseshoe orbit, the asteroid becomes temporarily "trapped" in the horseshoe's gap. To the left, we see a three-quarters perspective view of the motion of 2002 AA29 at this time. Note the Earth, rather faint in this image, in the middle of the asteroid's loops, and the Sun in the background. The blue dots outline the Earth's orbit.

During this time, the asteroid remains, properly speaking, in orbit around the Sun. Asteroid 2002 AA29 travels once around the Sun each year, as does the Earth. However, since the planet and asteroid orbit in the same amount of time, they remain close to each other throughout their journey. An analogy would be two cars (the planet and the asteroid) traveling with near-equal speeds around a circular race track (their orbit around the Sun). Both cars will remain near each other because of their similar velocities without there necessarily being any physical connection (eg. strong gravity) between them. An MPEG clip shows the motion in more detail.

To the right is another view, this time looking along the Earth's orbit. The Sun is off the image to the right here. We see that, though trapped in the neighbourhood of our planet, 2002 AA29 loops safely around us. Because there are slight differences between the velocities of Earth and 2002 AA29, they do not remain completely stationary with respect to one another. Rather, the asteroid drifts slightly and as a result, loops around our planet over the course of a year. Hence the name "quasi-satellite". You can learn more about this kind of behaviour at our quasi-satellite page.

After a while, 2002 AA29 will escape from quasi-satellite mode and go back to horseshoe mode. The last period of quasi-satellite motion was in about 550 A.D.; the next will be in 2600 A.D. or so. This ability to make the transition from horseshoe to quasi-satellite motion is part of what makes 2002 AA29 so interesting: no other asteroids are known to do this. It also has a very low eccentricity e (only 0.012 at discovery, less even than the Earth's very small 0.0167) compared to the average of 0.29 for near-Earth asteroids in general. As a result, its orbit is almost circular, and matches the shape of the Earth's closely. It is the tilt or inclination i of 2002 AA29, a modest 10 degrees, that keeps the two objects orbits apart; otherwise they would lie almost on top of each other. The effect of the small eccentricity and more substantial inclination can be seen in the images above. They result in the asteroid's loops being elongated in the up-down direction (due to i) but narrow across the middle (due to the small e).



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Recommend Delete Message 3 of 5 in Discussion
From: prometheuspan Sent: 1/26/2006 5:42 PM
List of numbered Aten asteroids
This is a list of all numbered Aten asteroids as of June 2005. See also Aten asteroids (category) for a list of all Aten asteroids that have articles.

Name Year Discoverer
99942 Apophis
(99907) 1989 VA
(96590) 1998 XB
(88213) 2001 AF2
(87684) 2000 SY2
(87309) 2000 QP
(86667) 2000 FO10
(86450) 2000 CK33
(85989) 1999 JD6
(85953) 1999 FK21
(85770) 1998 UP1
(68347) 2001 KB67 2001 LINEAR
(66400) 1999 LT7 1999 LINEAR
(66391) 1999 KW4 1999 LINEAR
(66146) 1998 TU3 1998 LINEAR
(66063) 1998 RO1 1998 LINEAR
(65679) 1989 UQ 1989 Christian Pollas
(33342) 1998 WT24 1998 LINEAR
(5604) 1992 FE 1992 Robert H. McNaught
(5590) 1990 VA 1990 Spacewatch
5381 Sekhmet 1991 Carolyn S. Shoemaker
3753 Cruithne 1986 J. Duncan Waldron
3554 Amun 1986 Carolyn S. Shoemaker, Eugene M. Shoemaker
3362 Khufu 1984 R. Scott Dunbar, Maria A. Barucci
2340 Hathor 1976 Charles T. Kowal
2100 Ra-Shalom 1978 Eleanor F. Helin
2062 Aten 1976 Eleanor F. Helin


Name Year Discoverer
99942 Apophis
(99907) 1989 VA
(96590) 1998 XB
(88213) 2001 AF2
(87684) 2000 SY2
(87309) 2000 QP
(86667) 2000 FO10
(86450) 2000 CK33
(85989) 1999 JD6
(85953) 1999 FK21
(85770) 1998 UP1
(68347) 2001 KB67 2001 LINEAR
(66400) 1999 LT7 1999 LINEAR
(66391) 1999 KW4 1999 LINEAR
(66146) 1998 TU3 1998 LINEAR
(66063) 1998 RO1 1998 LINEAR
(65679) 1989 UQ 1989 Christian Pollas
(33342) 1998 WT24 1998 LINEAR
(5604) 1992 FE 1992 Robert H. McNaught
(5590) 1990 VA 1990 Spacewatch
5381 Sekhmet 1991 Carolyn S. Shoemaker
3753 Cruithne 1986 J. Duncan Waldron
3554 Amun 1986 Carolyn S. Shoemaker, Eugene M. Shoemaker
3362 Khufu 1984 R. Scott Dunbar, Maria A. Barucci
2340 Hathor 1976 Charles T. Kowal
2100 Ra-Shalom 1978 Eleanor F. Helin
2062 Aten 1976 Eleanor F. Helin

-----------------------

The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 10 km, approximately the size of the Chicxulub object whose impact killed off the dinosaurs.

Well-known Apollo asteroids include:

Name Year Discoverer
2004 AS1 2004 LINEAR
1998 KY26 1998 Spacewatch
1997 XR2 1997 LINEAR
69230 Hermes 1937 Karl Reinmuth
(53319) 1999 JM8 1999 LINEAR
(52760) 1998 ML14 1998 LINEAR
(35396) 1997 XF11 1997 Spacewatch
(29075) 1950 DA 1950 Carl A. Wirtanen
25143 Itokawa 1998 LINEAR
6489 Golevka 1991 Eleanor F. Helin
4769 Castalia 1989 Eleanor F. Helin
4660 Nereus 1982 Eleanor F. Helin
4581 Asclepius 1989 Henry E. Holt, Norman G. Thomas
4486 Mithra 1987 Eric Elst, Vladimir Shkodrov
(4197) 1982 TA 1982 Eleanor F. Helin, Eugene Shoemaker
4183 Cuno 1959 Cuno Hoffmeister
4179 Toutatis 1989 Christian Pollas
4015 Wilson-Harrington 1979 Eleanor F. Helin
3200 Phaethon 1983 Simon Green, John K. Davies / IRAS
2101 Adonis 1936 Eugène Joseph Delporte
2063 Bacchus 1977 Charles T. Kowal
1866 Sisyphus 1972 Paul Wild
1862 Apollo 1932 Karl Reinmuth
1685 Toro 1948 Carl A. Wirtanen
1620 Geographos 1951 Albert George Wilson, Rudolph Minkowski
1566 Icarus 1949 Walter Baade

Amor asteroid
The Amor asteroids are a group of near-Earth asteroids named after the asteroid 1221 Amor. They approach the orbit of the Earth from beyond, but do not cross it. Most Amors do cross the orbit of Mars. The two moons of Mars, Deimos and Phobos, may be Amor asteroids that were somehow captured by the Red Planet.

The most famous member of this group is 433 Eros, which was the first asteroid to be orbited and then landed upon by a human probe (NEAR Shoemaker).


Populations
There are over 1200 Amor asteroids known today. Under 200 of them are numbered, and over 50 of them are named.


Subdivisions by semi-major axis
Amor asteroids can be partitioned into four sub-groups, depending on their average distance from the Sun.


Amor I
The Amor I subgroup consists of Amor asteroids whose semi-major axes are in between Earth and Mars. That is, they have a semi-major axis between 1.000 and 1.523 au. Less than one fifth of Amor asteroids belong to this subgroup. Amor I asteroids have lower eccentricities than the other subgroups of Amors.

Some Amor I asteroids, such as 15817 Lucianotesi, do not cross the orbit of Mars. They can be considered a part of an Earth-Mars belt. However, not all asteroids located entirely between the orbits of Earth and Mars are Amors.

Amor I asteroids that do cross the orbit of Mars (like 433 Eros), do so from the inside.

Amor I asteroids that have semi-major axes very close to Earth's (such as 1992 JD) can be considered Arjuna asteroids because they have very low eccentricities and thus Earth-like orbits.


Amor II
The Amor II subgoup has a semi-major axis between that of Mars (1.52 au) and the Main Asteroid Belt (2.12 au). About a third of Amors, including 1221 Amor, belong to this group. They have moderate eccentricities (from 0.17 to 0.52), and all cross the orbit of Mars from the outside. Their orbits usually take them out into the asteroid belt.


Amor III
Almost half of all Amor asteroids lie within the Main Asteroid Belt, and thus have semi-major axes between 2.12 and 3.57 au. These can be considered Main Belt Objects with high enough eccentricities to come near the Earth, usually 0.4 to 0.6.

Because their eccentricities are very large, about a third of Amor III asteroids have orbits that stretch beyond the asteroid belt and come within 1 au of Jupiter. 719 Albert and 1036 Ganymed are two such asteroids. The most extreme Amor III asteroids (such as 5370 Taranis) are actually Jupiter crossers.

Because they lie within the Main Asteroid Belt, several Amor III asteroids also belong to subgroups of the asteroid belt. For instance, the first Alinda asteroid (in 1:3 resonance with Jupiter and 4:1 resonance with Earth) discovered was 887 Alinda.


Amor IV
There are only a few known Amor asteroids whose average distance from the Sun is beyond the asteroid belt. Their semi-major axes are greater than 3.57 au and they are considered Amor IV asteroids. They are all Jupiter-crossers. Though they have very high eccentricities (0.65 to 0.75), they are not as eccentric as most Damocloids and comets, which tend to have have eccentricities around 0.9. The only numbered and named Amor IV asteroid is 3552 Don Quixote. So far, no Amor asteroid has been discovered that crosses the orbit of Saturn.


Cross-Populations

Outer Earth-Grazer Asteroids
An Outer Earth-Grazer asteroid is an asteroid which is normally beyond the Earth, but which can get closer to the Sun than the Earth at its furthest from the Sun (its aphelion, 1.0167 au), but not closer than Earth at its closest (its perihelion, 0.9833 au). In other words, the asteroid's perihelion is further from the Sun than Earth's perihelion, but closer to the Sun than Earth's aphelion. Outer Earth-Grazer asteroids are split between Amor and Apollo asteroids, depending on the definition you use.

If you use the simple definition of an Amor (1.3000 au > perihelion > 1.0000 au), then asteroids whose perihelion is between 1.0000 au (Earth's Semi-Major Axis) and 1.0167 au (Earth's aphelion) are Amor Outer Earth-Grazer asteroids, while those between 0.9833 au (Earth's perihelion) and 1.0000 au are considered Apollo Outer Earth-Grazer asteroids.

If you use the more precise definition of an Amor, those Outer Earth-Grazers which never get closer to the Sun than the Earth does (at any angle along its orbit) are Amors, and those that do are Apollos. Some "simple" Amor asteroids are also "precise" Apollos, while some "precise" Amors are also "simple" Apollos. Which definition you use is only relevant to Outer Earth-grazers.


Potentially Hazardous Asteroids
Most Potentially hazardous asteroids (PHA) are either Aten asteroids or Apollo asteroids, and therefore cross the orbit of the Earth. However, one tenth of PHAs are Amor asteroids. In order to be considered a PHA, its orbit has to get within 0.05 au from the Earth's orbit and the object has to be "big enough" to be a threat. An Amor asteroid therefore has to have a perihelion of less than 1.05 au to be considered a PHA. About a fifth of Amors come this close to the Sun, and about a fifth of these are actually PHAs. Of the fifty known Amor PHAs, 2061 Anza, 3908 Nyx and 3671 Dionyses have permanent names.


Earth-Crossing Asteroids
Although by definition no Amor asteroid actually currently crosses the Earth's orbit (see Earth-crosser asteroid), the definition of an Earth-crossing asteroid (ECA) is broad enough so that many, if not most, Amor asteroids are also ECAs. An ECA has to be able to some day cross the orbit of the Earth, not just today. If an Amor makes an approach close enough to the Earth, Mars, or Jupiter, it is possible that the gravitational effect of that encounter will alter the asteroid's orbit. Repeated close encounters may eventually cause the planet to cross the Earth's orbit. If astronomers determine that this can happen, the Amor asteroid is classified as an Earth-crossing asteroid. Of course, after its orbit has changed, it will no longer be an Amor asteroid, and will be reclassified as an Apollo asteroid and Earth-crosser asteroid. It can take many years of observation before an asteroid can be classified as an ECA.


Well known Amors
Name Year Discoverer
3908 Nyx 1980 Hans-Emil Schuster
1221 Amor 1932 Eugène Joseph Delporte
1036 Ganymed 1924 Walter Baade
887 Alinda 1918 Max Wolf
719 Albert 1911 Johann Palisa
433 Eros 1898 Gustav Witt

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Recommend Delete Message 4 of 5 in Discussion
From: prometheuspan Sent: 1/26/2006 5:43 PM
Name Provisional
Designation
433 Eros 1898 DQ
719 Albert 1911 MT
887 Alinda 1918 DB
1036 Ganymed 1924 TD
1221 Amor 1932 EA1
1580 Betulia 1950 KA
1627 Ivar 1929 SH
1915 Quetzálcoatl 1953 EA
1916 Boreas 1953 RA
1917 Cuyo 1968 AA
1943 Anteros 1973 EC
1980 Tezcatlipoca 1950 LA
2059 Baboquivari 1963 UA
2061 Anza 1960 UA
2202 Pele 1972 RA
2368 Beltrovata 1977 RA
2608 Seneca 1978 DA
3102 Krok 1981 QA
3122 Florence 1981 ET3
3199 Nefertiti 1982 RA
3271 Ul 1982 RB
3288 Seleucus 1982 DV
3352 McAuliffe 1981 CW
3551 Verenia 1983 RD
3552 Don Quixote 1983 SA
3553 Mera 1985 JA
3671 Dionysus 1984 KD
3691 Bede 1982 FT
3908 Nyx 1980 PA
4055 Magellan 1985 DO2
4401 Aditi 1985 TB
4487 Pocahontas 1987 UA
4503 Cleobulus 1989 WM
4587 Rees 3239 T-2
4947 Ninkasi 1988 TJ1
4954 Eric 1990 SQ
4957 Brucemurray 1990 XJ
5424 Lyapunov 1987 SL
5370 Taranis 1986 RA
5653 Camarillo 1992 WD5
5751 Zao 1992 AC
5797 Bivoj 1980 AA
5863 Tara 1983 RB
5869 Tanith 1988 VN4
5879 Almeria 1992 CH1
6456 Golombek 1992 OM
7088 Ishtar 1992 AA
7336 Saunders 1989 RS1
7358 Oze 1995 YA3
7480 Norwan 1994 PC
8013 Gordonmoore 1990 KA
8034 Akka 1992 LR
9172 Abhramu 1989 OB
11284 Belenus 1990 BA
15817 Lucianotesi 1994 QC
16912 Rhiannon 1998 EP8
20460 Robwhitely 1999 LO28
65803 Didymos 1996 GT

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Recommend Delete Message 5 of 5 in Discussion
From: MSN NicknamekeptinSpock Sent: 3/2/2006 3:28 PM
Delta-v for spacecraft flybys with all known near-Earth asteroids (q < 1.3 AU)

Delta-v is computed following the approach described by Shoemaker and Helin (1978), Earth-approaching asteroids as targets for exploration, NASA CP-2053, pp. 245-256. Last updated Thu Feb 2 16:25:55 PST 2006 Source for NEA orbits: Minor Planet Center cfa-www.harvard.edu/iau/lists/Atens.html cfa-www.harvard.edu/iau/list...llos.html cfa-www.harvard.edu/iau/lists/Amors.html N = 3842 Provisional Delta-v H a e
posted by:
prometheusPAN
California
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