In The Sky This Month – April 2011

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of April 2011.

April 2011 Highlights
* Saturn is the only easily visible planet
* The rest of the naked eye planets congregate in the morning sky at the end of the mont

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Apr 3 - New Moon
Apr 7 - Moon 2° from Pleiades
Apr 8 - Moon 7° from bright star Aldebaran
Apr 11 - First Quarter Moon 9° from bright star Pollux
Apr 12 - Moon 5° from Beehive Cluster
Apr 14 - Moon 5° from bright star Regulus
Apr 17 - Moon 8° from Saturn and 2.5° from bright star Spica
Apr 18 - Full Moon
Apr 20 - Moon 3° from bright star Antares
Apr 25 - Third Quarter Moon
Apr 30 - Moon 6.6° from Venus

Saturn – This month Saturn is at opposition. As a result, the ringed planet is at its brightest for the year (magnitude +0.4) and is also visible all night long though it is best around midnight. At the start of the month Saturn may be too low in the SE at dusk to be easily seen but by month’s end it is far enough off the horizon at dusk to be easily seen. Saturn is a slow moving planet and takes 29 years to circle the Sun as well as 29 years to do one circuit around the ecliptic constellations. As has been the case all year long, Saturn is still located in Virgo about 11-13° from 1st magnitude Spica.

Apr 3 - Saturn at Opposition
Apr 17 - Saturn and Moon 8° apart

Venus, Mercury, Mars and Jupiter -  The long slow grind towards superior conjunction continues. This month Venus rises only an hour or so before the Sun and never gets very high in the ESE to E sky. Though Venus is a difficult sight for northern observers it is worth searching out at the end of April. During the last week of the month (and into May) Venus will be visited by 3 planets in the best planetary alignment of the year. Starting around the 25th, Mercury peaks above the eastern horizon 40 minutes before sunrise. Over the next few nights, Mars and Jupiter join the show. Use the crescent Moon on the 29th and 30th to point the way.

Apr 30 - Moon 6.6° from Venus

Meteors

Meteor activity is near a seasonal minimum in April. The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During April mornings, 10-12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Lyrids (LYR)

The Lyrids are usually good for 10-20 meteors per hour under a dark sky. This month the just past Full Moon will make the shower difficult to observe. So these remnants of Comet Thatcher will probably go unobserved except by automated video systems and only the most dedicated of visual observers.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2011 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month…

Binocular Comets (V = 6.0 – 8.0)

None this month…

Small Telescope Comets (V = 8.0 – 10.0)

C/2011 C1 (McNaught)

It seems the past couple of years have seen a bright Comet McNaught and this year is no different. The 58th comet discovery by Rob McNaught and 74th from Siding Spring Observatory, C/2011 C1 was first seen on February 10th of this year. Though intrinsically faint, the comet is currently being reported as bright as magnitude 9.0. CCD images taken by the author on Apr 1 UT confirm that the comet is between magnitude 9.0 and 9.5 at this time (see image below). Unfortunately this will probably be as bright as the comet gets as it passes perihelion on April 17 at a distance of 0.88 AU from the Sun. It is also slowly moving away from Earth with a geocentric distance of 0.95, 1.06 and 1.22 AU from Earth at the star, middle and end of the month. Comet C/2011 C1 travels the length of Aquarius before ending the month near the Pisces/Pegasus border.

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Asteroids

Binocular and Small Telescope Asteroids (V < 8.0)

(4) Vesta

Vesta is the brightest asteroid in the Main Belt. This is due to its high albedo (or reflectivity) which causes it to reflect ~42% of the light that strikes it. Vesta is also peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta has dimensions of 347x336x275 miles or 578×560×458 km.

The maps below were created from images taken with the Hubble Space Telescope. The geography is dominated by a large impact crater located near the south pole (the blue ‘donut’ in the elevation map). Perhaps this crater is the result of the impact that blasted off the smaller V-type asteroids. We’ll know more this summer when NASA’s Dawn spacecraft enters orbit around Vesta for a full year. Currently the encounter is scheduled for July 2011 to July 2012.

Images and models of the shape of asteroid (4) Vesta. In the upper left is a real HST image, to the upper right is a model of Vesta’s shape, and on the bottom is an elevation map . Credit: NASA/STScI.

Vesta spends the month around magnitude 7.6 to 7.3 as it moves eastwards through western Capricornus.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.

In The Sky This Month – February 2011

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of February 2011.

February 2011 Highlights
* Jupiter rules the evening sky, while...
* Saturn becomes visible later in the evening...
* Venus continues to dominate the early morning sky.

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Feb 1 - Moon 3.5° from Mercury
Feb 3 - New Moon
Feb 7 - Moon 6° from Jupiter and Uranus
Feb 11 - First Quarter Moon
Feb 11 - Moon 1.4° from Pleiades
Feb 12 - Moon 7° from bright star Aldebaran
Feb 15 - Moon 9° from bright star Pollux
Feb 16 - Moon 4° from Beehive Cluster
Feb 18 - Full Moon 5° from bright star Regulus
Feb 21 - Moon 7.5° from Saturn and 2.6° from bright star Spica
Feb 24 - Third Quarter Moon
Feb 25 - Moon 3° from bright star Antares

Jupiter - The ‘King of the Planets’ continues its reign as the uncontested ‘King of the Evening Sky’ at magnitude -2.1. Located on the Pisces/Aquarius border, Jupiter is easy to find in the southwest as it gets dark.

Feb 7 - Moon 6° from Jupiter

Saturn – Saturn rises during the late hours of the evening. Located in Virgo, the ringed planet is a close match in brightness (mag +0.6) to Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 8-9° of Spica.

Feb 21 - Moon 7.5° from Saturn

Venus – After passing through inferior conjunction in late October , Venus is now the dominant sight just before dawn. On Feb 1, Venus rises almost 3 hours before the Sun in the eastern sky though this drops to 2 hours over the course of the month. Unlike this year’s evening apparition which was poorly placed, Venus’ current stay in the morning sky will be a good one for northern observers. Through a telescope it currently looks like a brilliant ‘half moon’.

Mercury and Mars – Too close to the Sun for observation.

Meteors

Meteor activity is at a seasonal minimum in February. The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During February mornings, 10-12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None this month…

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month…

Binocular Comets (V = 6.0 – 8.0)

None this month…

Small Telescope Comets (V = 8.0 – 10.0)

None

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(7) Iris

Iris is an inner Main-Belt asteroid that can occasionally get as bright as any asteroid. This year, Iris did not get as bright but was still become a binocular object at opposition on January 24 at magnitude 7.9. This month it is located in the constellation of Cancer a few degrees to the southwest of the Beehive Cluster. It starts the month at magnitude 8.1, but fades to 8.9 by the end of the month.

With a size of 240 x 200 x 200 km, Iris is the 5th largest stoney S-type asteroid. It was discovered in 1847 by John Russel Hind, the 1st of 10 asteroids he discovered.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Iris from Heavens Above.

In The Sky This Month – December 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of December 2010.

December 2010 Highlights
* Great Total Lunar Eclipse for the Americas and Eastern Asia on Dec 21
* Geminid Meteor Shower peaks on Dec 14
* Jupiter dominates the evening sky, while…
* Venus dominates the morning sky
* Comet 103P/Hartley 2 slowly fades as it moves away from the Earth and Sun

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The big event this month is a Total Lunar Eclipse on the night of Dec 20/21. The Moon will be located nearly overhead during the peak of the eclipse for North American observers.

The start of the umbral eclipse (when the darkest part of Earth’s shadow covers the Moon) will occur at 6:32 UT (1:32 EST / 12:32 CST / 11:32 MST / 10:32 PST) with mid-eclipse at 8:16 UT (3:16 EST / 2:16 CST / 1:16 MST / 12:16 PST)

The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Dec 1 - Moon 7° from Saturn
Dec 2 - Moon 6° from Venus and 3° from Spica
Dec 5 - New Moon
Dec 6 - Moon 0.8° from Mars
Dec 7 - Moon 2° from Mercury
Dec 11 - Moon 5° from Neptune
Dec 13 - First Quarter Moon 7° from Jupiter
Dec 14 - Moon 6° from Uranus
Dec 19 - Moon 1.5° from Pleiades and 8° from Aldebaran
Dec 21 - Full Moon and Total Lunar Eclipse
Dec 23 - Moon 8° from Pollux
Dec 24 - Moon 4° from Beehive Cluster
Dec 25 - Moon 5° from Regulus
Dec 28 - Third Quarter Moon 7° from Saturn
Dec 29 - Moon 3° from Spica
Dec 31 - Moon 7° from Venus

Mercury – Mercury is in the middle of a evening apparition at the start of the month. It’s all downhill (literally) after that as the innermost planet creeps back into the bright twilight and out of view by mid-month. At the end of the month Mercury is back as it peeks above the SE horizon right before dawn.

Dec 1 - Greatest Elongation East
Dec 7 - Moon 2° from Mercury 

Mars - Mars is practically out of view this month for most of us. Those with exceptionally clear skies and unobstructed view of the SW sky in the evening might still catch a glimpse of this +1.3 magnitude planet.

Dec 6 - Moon 0.8° from Mars

Jupiter (and Uranus, too...) - The 'King of the Planets' continues his reign as the uncontested 'King of the Evening Sky'. though fading from magnitude -2.5 to -2.3, nothing but the Moon rivals it in brightness. Located on the Pisces/Aquarius border, Jupiter is easy to find in the south-south-east as it gets dark.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or its large atmospheric belts (there are usually 2 prominent belts but 1 has recently disappeared though it may make a comeback at any time). In addition, Jupiter is within 2.9° of +5.8 magnitude Uranus on Dec 1 and 0.7° on Dec 31.

Dec 13 - First Quarter Moon 7° from Jupiter

Saturn - Saturn rises a few hours before the Sun. Located in Virgo, the ringed planet is a close match in brightness (mag +0.9) to the Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 9-10° of Spica. It's rings are slowly opening up and are currently 9° from edge-on.

Dec 1 - Moon 7° from Saturn
Dec 28 - Moon 7° from Saturn

Venus - After passing through inferior conjunction in late October , Venus is now the dominant sight in the morning sky. On Dec 1, Venus rises 3 hours before the Sun in the eastern sky. By the end of the month, it is up almost 4 hours before sunrise. Unlike this year's evening apparition which was poorly placed, Venus' current stay in the morning sky will be a good one for northern observers.

Dec 2 - Venus at its brightest (magnitude -4.5 to -4.9 depending on the source)
Dec 2 - Moon 6° from Venus
Dec 31 - Moon 7° from Venus

Meteors

Meteor activity is still quite high in December. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Geminids (GEM) [Max Date = Dec 14, Max Rate = ~60-120 per hour under dark skies]

Along with the Perseids of August, the Geminids are one of the best meteor showers delivering great displays year after year. This year's Geminids are nicely timed with the First Quarter Moon will be setting around midnight.

According to Sirko Molau's analysis of video data, the Geminids are already observable at the beginning of the month though their rates are very low. The peak is predicted for the night of December 13/14 though numerous meteors should be visible for a day or two on either side of the peak. With a radiant near the star Castor in the constellation of Gemini, the Geminids are one of the rare major showers that are observable before midnight and can be observed as early as 8:00 pm though rates are usually best after 10:00 pm (though with the caveat for this year that the Moon will spoil the show until it sets around midnight). Under a dark rural moon-less sky, the Geminids can produce as many as 100+ meteors per hour. Observers under suburban skies will see lower rates.

The Geminids are the result of the break-up and subsequent activity of the "asteroid" (3200) Phaethon. Why asteroid in quotes? Most meteor showers come from comets yet Phaethon is on a very non-cometary orbit and has never shown any cometary activity. There is still much scientific discussion about what exactly Phaethon is.

More details on the Geminids and their parent "asteroid" Phaethon will be posted as we get closer to its peak.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford's Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally's and Mark Davis's NAMN Notes, and the International Meteor Organization's 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 - 8.0)

Comet 103P/Hartley 2 - Comet 103P/Hartley 2 continues its retreat from the Earth and Sun. Well past its late October peak in brightness, the comet starts December around magnitude 6 and should steadily fade to around magnitude 8 by the end of the month.

.103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet's orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big comet, this year it passed 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.The comet starts the month at a distance of 1.16 AU from the Sun and 0.29 AU from Earth. By mid-month it will be 1.24 AU from the Sun and 0.36 AU from Earth. At the end of the month, Hartley 2 will be 1.36 AU and 0.46 AU from the Sun and Earth, respectively. 

Even though the comet is currently 6th magnitude and theoretically bright enough to be an easy binocular object, in reality this is a difficult object to observe. With a coma diameter approaching 1° across, the light of the comet is spread over a wide area. As a result, even small amounts of light pollution renders much of the coma invisible. Dark skies are always a plus and will help in observing this challenging comet.

The comet is located in the southern part of the winter Milky Way. The start of December sees the comet in Puppis just to the south of the bright open clusters M46 and M47. By the end of the month it will have retrograded into Canis Major. It is a morning object and is visible after midnight.

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On November 4 the NASA EPOXI (ex-Deep Impact) spacecraft encountered Hartley 2 giving us close-up views of the comet's nucleus. This is the xth comet visited by a spacecraft after Comets 21P/Giacobini-Zinner (1985), 1P/Halley (1986), 19P/Borelly (2001), 81P/Wild 2 (2004), 9P/Tempel 1 (2005). On February 15, 2011, Tempel 1 will be the first comet to be re-visited by a spacecraft.

A finder chart for Comet Hartley 2 can be found at Comet Chasing and Sky and Telescope.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida's Comet Homepage.

Small Telescope Comets (V = 8.0 - 10.0)

Comet P/2010 V1 (Ikeya-Murakami) - Probably the surprise comet of the year, Comet Ikeya-Murakami is a rare visual find. Not long ago most bright comets were discovered by amateur astronomers visually through the eyepiece of their telescopes without the help of computers. Nowadays, the professional surveys are able to scan large swathes of sky and with the help of digital CCD cameras and detection software find most comets.

The reason Ikeya and Murakami could discover P/2010 V1 is probably because it is a small and usually weakly or even inactive comet. The fact that the comet was not visible to other comet hunters (including Ikeya) a day or two before discovery suggests it has recently undergone an outburst. CCD images of its rapidly expanding coma also point to a recent event. At discovery the comet was as bright as magnitude 7.5 to 8.0. At the start of this month the comet is around magnitude 9 to 10 and, baring another outburst, should quickly fade.

Another interesting thing about this comet is its orbit. With an aphelion of only ~4.2 AU, the comet does not extend far enough to reach the orbit of Jupiter. Unlike most cometary orbits, this orbit is very asteroidal and suggests that it more closely related to volatile-rich Main belt comets than the typical comet from the outer Solar System.

Perihelion occurred on 2010 Oct. 11 at 1.57 AU. The comet is now outbound and at mid-month is located 1.68 AU from the Sun and 2.21 AU from Earth. Starting the month in Virgo the comet will cross into Libra by mid-month.

A finder chart for Comet Ikeya-Murakami can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida's Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(7) Iris

Iris is an inner Main-Belt asteroid that can occassionally get as bright as any asteroid. This year, Iris will not get as bright but will still become a binocular object at opposition on January 24 at magnitude 7.9. During December, it is located in the constellation of Cancer a few degrees to the southwest of the Beehive Cluster. It starts the month at magnitude 8.9 and ends it at magnitude 8.3.

With a size of 240 x 200 x 200 km, Iris is the 5th largest stoney S-type asteroid. It was discovered in 1847 by John Russel Hind, the 1st of 10 asteroids he discovered.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

Recent Discoveries – Nov 7 to 18

The past week or so has seen the announcement of 57 new NEAs. The discovery tally breaks down as such: 27 Mount Lemmon, 13 Catalina, 11 LINEAR, 3 PANSTARRS, 2 Spacewatch, 1 Siding Spring.

A handful of the objects made very close approaches to Earth. The most interesting being 2010 WA. With an H of 30.0, this object is one of the smallest asteroids ever observed at a size of 2 to 6 meters across. It made it passed closest to Earth around 4 hours UT on November 17 at a distance of 0.00026 AU (or just over 24,000 miles or 38,000 km). That is only a tenth of the distance to the Moon. Such a small miss distance makes 2010 WA the 7th closest approach to the Earth by an asteroid (that we know of, there have probably been many many more little ones that passed sight unseen).

Asteroid   Type   Mag    MOID     a     e     i     H   Discoverer      MPEC
2010 WJ    Amor    18   0.469   1.86  0.30  27.7  17.9  LINEAR          2010-W12
2010 WH    Amor    19   0.445   2.39  0.47  21.9  18.9  LINEAR          2010-W11
2010 WC    Aten    18   0.004   0.81  0.35   7.6  25.3  Catalina        2010-W06
2010 WB    Apollo  16   0.005   1.35  0.29   5.5  23.8  Catalina        2010-W05
2010 WA    Apollo  20   0.0002  2.00  0.57   6.5  30.0  Mount Lemmon    2010-W03
2010 VU198 Amor    21   0.311   1.81  0.38  30.6  18.4  Mount Lemmon    2010-W08
2010 VW194 Apollo  17   0.001   1.79  0.46   2.0  26.3  LINEAR          2010-W04
2010 VY190 Amor    17   0.298   1.77  0.28  20.5  18.6  Mount Lemmon    2010-V148
2010 VC140 Apollo  18   0.002   1.50  0.34   1.5  27.8  Catalina        2010-V147
2010 VB140 Apollo  20   0.004   2.29  0.58   3.2  24.9  Catalina        2010-V146
2010 VA140 Apollo  20   0.002   1.70  0.47   4.6  26.4  Mount Lemmon    2010-V145
2010 VZ139 Amor    18   0.058   1.13  0.07   8.9  23.0  Catalina        2010-V144
2010 VY139 Amor    19   0.088   2.42  0.56   9.4  20.4  LINEAR          2010-V143
2010 VX139 Aten    19   0.095   0.96  0.16  21.3  20.4  LINEAR          2010-V142
2010 VW139 Amor    19   0.061   1.62  0.37  10.4  24.2  Mount Lemmon    2010-V141
2010 VV139 Apollo  19   0.064   1.17  0.16  31.5  21.8  Mount Lemmon    2010-V140
2010 VR139 Apollo  19   0.002   1.70  0.46   2.1  26.8  Catalina        2010-V138
2010 VQ139 Apollo  21   0.001   1.99  0.55   1.4  29.2  Mount Lemmon    2010-V137
2010 VP139 Apollo  20   0.0008  1.12  0.21   1.7  29.1  Mount Lemmon    2010-V136
2010 VO139 Apollo  20   0.008   2.08  0.70   7.7  26.5  Mount Lemmon    2010-V135
2010 VN139 Apollo  19   0.026   1.87  0.74   1.5  24.4  Mount Lemmon    2010-V134
2010 VM139 Apollo  20   0.012   1.42  0.29   9.6  25.4  Mount Lemmon    2010-V133
2010 VL139 Apollo  21   0.006   1.86  0.51   3.6  26.8  Mount Lemmon    2010-V132
2010 VK139 Aten    16   0.008   0.78  0.29  27.9  23.4  Catalina        2010-V131
2010 VJ139 Apollo  21   0.065   1.35  0.37   8.9  22.0  Mount Lemmon    2010-V130
2010 VF139 Amor    20   0.125   2.51  0.56   1.6  23.9  Mount Lemmon    2010-V128
2010 VE139 Amor    20   0.224   2.42  0.50   6.8  22.1  Mount Lemmon    2010-V127
2010 VD139 Aten    20   0.013   0.85  0.24   3.8  26.0  Mount Lemmon    2010-V126
2010 VD99  Apollo  20   0.045   1.84  0.52   8.0  24.5  Spacewatch      2010-V125
2010 VB99  Apollo  18   0.053   1.34  0.40  49.9  21.3  LINEAR          2010-V122
2010 VA99  Apollo  18   0.042   1.44  0.40  37.2  22.7  LINEAR          2010-V121
2010 VW98  Amor    19   0.123   1.60  0.33  12.1  22.1  Mount Lemmon    2010-V119
2010 VV98  Apollo  18   0.002   1.98  0.58   1.6  24.5  LINEAR          2010-V118
2010 VU98  Apollo  20   0.029   1.01  0.26   6.9  24.7  Mount Lemmon    2010-V117
2010 VQ98  Apollo  19   0.002   1.04  0.05   1.7  27.9  Catalina        2010-V114
2010 VP98  Apollo  20   0.119   1.34  0.29  22.7  24.5  Mount Lemmon    2010-V113
2010 VO98  Apollo  20   0.028   1.45  0.45   7.8  25.3  Mount Lemmon    2010-V112
2010 VN98  Amor    19   0.116   1.53  0.29  27.1  22.0  LINEAR          2010-V111
2010 VA76  Amor    21   0.124   2.14  0.49   3.9  26.9  PANSTARRS       2010-V103
2010 VZ75  Amor    22   0.175   1.52  0.24  11.5  25.5  PANSTARRS       2010-V102
2010 VW75  Amor    21   0.050   2.34  0.55   1.0  21.7  Mount Lemmon    2010-V101
2010 VD72  Aten    17   0.015   0.92  0.18  19.2  21.8  Catalina        2010-V100
2010 VC72  Apollo  22   0.016   1.16  0.14   5.9  23.6  PANSTARRS       2010-V99
2010 VB72  Amor    19   0.124   1.22  0.09  16.3  20.6  Catalina        2010-V98
2010 VA72  Apollo  20   0.058   2.55  0.60   3.5  23.1  Mount Lemmon    2010-V97
2010 VZ71  Apollo  20   0.297   3.24  0.69  23.9  19.2  Mount Lemmon    2010-V96
2010 VY71  Amor    19   0.071   2.55  0.58   3.0  24.1  Catalina        2010-V95
2010 VS71  Apollo  18   0.015   1.43  0.66   2.3  23.8  Catalina        2010-V93
2010 VN65  Apollo  19   0.227   1.63  0.41  23.9  20.1  Spacewatch      2010-V92
2010 VM65  Apollo  18   0.055   1.06  0.03  24.8  23.5  Catalina        2010-V91
2010 VL65  Apollo  19   0.007   1.07  0.14   4.7  28.4  LINEAR          2010-V86
2010 VC40  Amor    21   0.179   2.51  0.54   6.6  24.0  Mount Lemmon    2010-V83
2010 VB40  Amor    20   0.075   2.78  0.62   3.4  24.7  Mount Lemmon    2010-V82
2010 VA40  Apollo  20   0.036   2.40  0.57   2.0  26.3  Mount Lemmon    2010-V81
2010 VX39  Apollo  19   0.065   1.84  0.43  11.4  19.1  LINEAR          2010-V78
2010 SC41  Apollo  21   0.001   1.86  0.61   0.2  19.5  Mount Lemmon    2010-V90
2010 RF181 Apollo  19   0.121   2.21  0.55   6.3  20.7  Siding Spring   2010-W13
Comet       Type       T        q     a     e      i  Mag  Period        MPEC 
None

Type
Aten -  Earth crossing with semi-major axis (avg distance from Sun) < 1 AU
Apollo - Earth crossing with semi-major axis (avg distance from Sun) > 1 AU
Amor - non-Earth crossing with perihelion distance < 1.3 AU
JFC - Jupiter family comet
HFC - Halley family comet
LPC - Long-period comet
MBC - Main belt comet
ECC - Suspected extinct or dormant (or just unrecognized) comet
T - Date of Perihelion
MOID - Minimum Orbit Intercept Distance, minimum distance between asteroid and Earth's orbit
a - semi-major axis, average distance from Sun in AU (1 AU = 93 million miles)
e - eccentricity
i - inclination
H - absolute magnitude
Mag - magnitude at discovery
Discoverer - survey or person who discovered the object
MPEC - Minor Planet Electronic Circular, the discovery announcement

Recent Discoveries – Oct 28 to Nov 2

We are approaching the mid point of the current lunation and the surveys are in full discovery mode. Clear weather in the SW US and Hawaii has helped.

Since the last ‘Recent Discovery’ post 30 new NEAs have been found.

Asteroid   Type   Mag    MOID     a     e     i     H   Discoverer      MPEC
2010 VK    Apollo  20   0.179   1.25  0.40  33.5  21.4  Mount Lemmon    2010-V21
2010 VJ    Amor    20   0.236   2.51  0.51   8.3  22.4  Mount Lemmon    2010-V20
2010 VH    Amor    22   0.066   1.79  0.41  11.4  27.1  Mount Lemmon    2010-V19
2010 VG    Amor    21   0.188   1.30  0.11  14.6  23.9  Mount Lemmon    2010-V18
2010 VF    Apollo  21   0.016   1.85  0.75   3.7  25.6  Mount Lemmon    2010-V17
2010 VE    Apollo  19   0.143   1.54  0.48   9.2  19.8  Catalina        2010-V16
2010 VB    Aten    19   0.012   0.92  0.33   5.2  25.3  Spacewatch      2010-V12
2010 UL8   Apollo  22   0.102   1.55  0.35  14.7  24.0  PANSTARRS       2010-V15
2010 UK8   Apollo  19   0.654   2.19  0.70   1.9  20.0  Mount Lemmon    2010-V14
2010 UE8   Amor    21   0.084   1.45  0.27   2.6  25.0  Mount Lemmon    2010-V11
2010 UD8   Amor    19   0.072   1.42  0.26   4.7  24.1  Mount Lemmon    2010-V10
2010 UB8   Amor    20   0.193   3.00  0.63  31.1  19.8  WISE            2010-V08
2010 UZ7   Apollo  21   0.012   2.21  0.64   5.4  24.8  Mount Lemmon    2010-V05
2010 UY7   Aten    19   0.001   0.93  0.13   0.4  28.5  Catalina        2010-V04
2010 UX7   Apollo  19   0.138   1.64  0.38   7.8  20.6  Mount Lemmon    2010-V03
2010 UW7   Amor    20   0.132   2.63  0.58  17.3  24.0  Mount Lemmon    2010-V02
2010 UV7   Amor    20   0.172   1.14  0.60  32.9  22.4  Mount Lemmon    2010-V01
2010 UT7   Apollo  21   0.009   1.62  0.67  25.3  19.5  Mount Lemmon    2010-U71
2010 US7   Apollo  19   0.040   1.90  0.63  54.9  18.8  LINEAR          2010-U70
2010 UR7   Apollo  19   0.006   2.28  0.62   3.5  27.3  Mount Lemmon    2010-U69
2010 UQ7   Apollo  17   0.016   2.40  0.67   4.5  19.9  Catalina        2010-U68
2010 UP7   Apollo  21   0.071   1.45  0.31  10.9  25.7  Mount Lemmon    2010-U66
2010 UO7   Amor    19   0.112   1.88  0.42   1.5  23.7  Catalina        2010-U65
2010 UM7   Apollo  19   0.003   2.78  0.68   4.5  27.6  Mount Lemmon    2010-U63
2010 UL7   Amor    20   0.247   3.04  0.60  22.3  21.6  Mount Lemmon    2010-U62
2010 UJ7   Aten    19   0.001   0.79  0.33  13.0  25.6  LINEAR          2010-U59
2010 UH7   Amor    19   0.248   3.08  0.60  16.4  18.9  Catalina        2010-U57
2010 UG7   Apollo  19   0.023   2.30  0.78  16.2  21.4  Mount Lemmon    2010-U56
2010 UF7   Apollo  20   0.118   2.20  0.57   8.2  19.2  Mount Lemmon    2010-U52
2010 UE7   Apollo  18   0.153   1.83  0.71   9.4  19.1  Siding Spring   2010-U51

Comet       Type       T        q     a     e      i  Mag  Period        MPEC 
None

Type
Aten -  Earth crossing with semi-major axis (avg distance from Sun) < 1 AU
Apollo - Earth crossing with semi-major axis (avg distance from Sun) > 1 AU
Amor - non-Earth crossing with perihelion distance < 1.3 AU
JFC - Jupiter family comet
HFC - Halley family comet
LPC - Long-period comet
MBC - Main belt comet
ECC - Suspected extinct or dormant (or just unrecognized) comet
T - Date of Perihelion
MOID - Minimum Orbit Intercept Distance, minimum distance between asteroid and Earth's orbit
a - semi-major axis, average distance from Sun in AU (1 AU = 93 million miles)
e - eccentricity
i - inclination
H - absolute magnitude
Mag - magnitude at discovery
Discoverer - survey or person who discovered the object
MPEC - Minor Planet Electronic Circular, the discovery announcement

Recent Discoveries – Oct 19 to 28

The past week saw only a few new asteroid discoveries. Due to bright sky conditions caused by the nearly Full Moon, most of the surveys go on hiatus for a few days. Now that the Moon is well past Full, discoveries are ramping up again.

Asteroid   Type   Mag    MOID     a     e     i     H   Discoverer      MPEC
2010 UC7   Apollo  18   0.004   1.89  0.57   5.2  24.6  Catalina        2010-U48
2010 UB7   Amor    19   0.243   2.46  0.50  11.2  21.9  Catalina        2010-U47
2010 UA7   Amor    20   0.173   2.41  0.51   3.7  23.3  Mount Lemmon    2010-U46
2010 UZ6   Amor    20   0.034   2.54  0.60   6.3  26.4  Mount Lemmon    2010-U45
2010 UY6   Amor    20   0.059   2.70  0.62  20.1  20.3  WISE            2010-U44
2010 UX6   Apollo  18   0.021   2.55  0.61   1.3  23.1  La Sagra        2010-U43
2010 UP    Apollo  18   0.017   1.07  0.10   9.3  24.5  LINEAR          2010-U27
2010 UO    Apollo  19   0.029   1.41  0.28   5.5  26.2  Mount Lemmon    2010-U26
2010 UM    Amor    20   0.203   1.94  0.38   3.9  21.7  Mount Lemmon    2010-U22
2010 TX168 Apollo  19   0.021   1.48  0.52  25.9  19.8  Catalina        2010-U25 

Comet       Type       T        q     a     e      i  Mag  Period        MPEC 
None

Type
Aten -  Earth crossing with semi-major axis (avg distance from Sun) < 1 AU
Apollo - Earth crossing with semi-major axis (avg distance from Sun) > 1 AU
Amor - non-Earth crossing with perihelion distance < 1.3 AU
JFC - Jupiter family comet
HFC - Halley family comet
LPC - Long-period comet
MBC - Main belt comet
ECC - Suspected extinct or dormant (or just unrecognized) comet
T - Date of Perihelion
MOID - Minimum Orbit Intercept Distance, minimum distance between asteroid and Earth's orbit
a - semi-major axis, average distance from Sun in AU (1 AU = 93 million miles)
e - eccentricity
i - inclination
H - absolute magnitude
Mag - magnitude at discovery
Discoverer - survey or person who discovered the object
MPEC - Minor Planet Electronic Circular, the discovery announcement

Recent Discoveries – Oct 12 to 18

2010 TW54 is the first of 4 small asteroids to buzz the Earth in the past week. I should rephrase that last sentence and say it is the first of 4 small asteroids that we know buzzed the Earth last week. For every small one we see, many hundreds pass by unseen. Luckily they are all too small to do anything more than cause a nice fireball light show and drop a few meteorites. Back to TW54, it passed within 0.0011 AU (102,000 miles / 163,000 km / 0.42 lunar distances) of Earth on October 9. At that time it had brightened to 14th magnitude though it would not be discovered for another 2 days.

2010 TN55 got up to 16th magnitude during its close approach to Earth on October 11. At its closest, this 7 to 24 meter across asteroid passed 0.0022 AU from Earth (or 205,000 miles / 327,000 km / 0.85 lunar distances). Having been found by Spacewatch , this is the only one of the 4 recent close approachers not found by the Mount Lemmon Survey

2010 UE flew past the Earth on October 16 at a close distance of 0.00073 AU. That works out to only 68,000 miles or 109,000 km or 0.28 lunar distances. Like most close calls this object is very small (2 to 7 meters across) and would never have survived passage through Earth’s atmosphere to reach the ground as anything more than a bunch of small meteorites.

2010 UJ is a yet another small asteroid (size between 10 and 40 meters across). Residing on an orbit that is not too different from Earth’s, this asteroid may make a good target for future manned and/or unmanned spacecraft missions. That is unless it gets lost which is common for such a small object that can not be observed except when very close to Earth. UJ will pass within 0.04 AU of Earth on Nov. 1 when it will shine at a faint magnitude of 19.9.

2010 UK passed 0.0056 AU (520,000 miles / 830,000 km / 2.2 lunar distances) from Earth on October 16. UK is between 10 and 30 meters across.

Three new Jupiter-family comets were found including the first comet discovered by the PANSTARRS survey. The other 2 were found by Catalina/Mount Lemmon observers Andrea Boattini and Rik Hill. This is Andrea’s 4th comet discovery of the year and 15th overall. For Rik, this is also his 4th of the year and 23rd overall.

P/2010 T2 (PANSTARRS) is a faint comet at ~20th magnitude. Even at perihelion next summer at a distant 3.73 AU it will only brighten to magnitude 19.5. This comet is a short-period Jupiter-family comet with a period of 13.2 years.

P/2010 U1 (Boattini) is a few months past perihelion. Right now it is at its brightest which is still a very faint 19th magnitude. With perihelion at 4.88 AU, this comet only comes a little closer than the orbit of Jupiter. This comet does not travel as far from the Sun as Saturn and its motion is dominated by Jupiter. Hence this is another short-period Jupiter-family comet. It orbits the Sun once every 17.2 years.

P/2010 U2 (Hill) is also a short-period Jupiter-family comet with a period of 8.88 years. Perihelion occurs next month at a distance of 2.56 AU. Its current brightness of 18th magnitude is as bright as this comet will get.

Asteroid   Type   Mag    MOID     a     e     i     H   Discoverer      MPEC
2010 UK    Aten    16   0.002   0.87  0.21   4.9  26.8  Mount Lemmon    2010-U17
2010 UJ    Aten    20   0.003   0.94  0.09   0.4  26.2  Mount Lemmon    2010-U16
2010 UH    Apollo  20   0.003   1.36  0.31   0.7  27.1  Mount Lemmon    2010-U15
2010 UG    Apollo  20   0.038   1.51  0.34   8.0  25.4  Mount Lemmon    2010-U14
2010 UE    Apollo  19   0.0003  2.63  0.71   3.1  29.6  Mount Lemmon    2010-U12
2010 UD    Apollo  15   0.014   1.10  0.26  26.3  21.3  Mount Lemmon    2010-U11
2010 UC    Aten    17   0.007   0.94  0.07   4.7  27.4  Catalina        2010-U10
2010 UB    Apollo  19   0.010   2.06  0.52   3.4  24.3  LINEAR          2010-U08
2010 UN167 Apollo  21   0.009   1.70  0.59   5.4  27.1  Mount Lemmon    2010-U06
2010 TM167 Apollo  21   0.085   1.16  0.48   5.1  20.9  Mount Lemmon    2010-U05
2010 TL167 Aten    21   0.114   0.97  0.64  12.5  22.4  Mount Lemmon    2010-U04
2010 TK167 Apollo  19   0.065   3.20  0.69  18.6  22.8  LINEAR          2010-U03
2010 TJ167 Amor    20   0.259   2.22  0.44   4.7  21.1  Mount Lemmon    2010-U02
2010 TS149 Apollo  20   0.027   1.50  0.39   3.4  19.8  Mount Lemmon    2010-118
2010 TS55  Amor    21   0.145   1.15  0.46   6.0  24.2  Mount Lemmon    2010-T117
2010 TR55  Amor    18   0.234   2.61  0.53  21.8  18.7  Catalina        2010-T116
2010 TP55  Apollo  21   0.002   2.06  0.62   3.1  20.4  PANSTARRS       2010-T115
2010 TO55  Apollo  17   0.006   1.68  0.41   4.8  26.5  Catalina        2010-T113
2010 TN55  Apollo  20   0.002   2.15  0.77   0.4  27.1  Spacewatch      2010-T112
2010 TL55  Apollo  21   0.120   2.45  0.64  29.6  19.0  Spacewatch      2010-T111
2010 TK55  Apollo  19   0.058   1.06  0.07  24.0  23.8  LINEAR          2010-T110
2010 TF55  Amor    20   0.118   2.63  0.58  12.9  24.0  Mount Lemmon    2010-T106
2010 TE55  Aten    18   0.002   0.93  0.13   1.9  28.1  Mount Lemmon    2010-T105
2010 TD55  Apollo  19   0.073   1.46  0.36  23.3  23.3  LINEAR          2010-T104
2010 TC55  Amor    18   0.121   2.78  0.61  19.7  19.9  Maticic&Zakrajsek010-T103
2010 TA55  Amor    21   0.194   1.52  0.25  15.5  21.9  PANSTARRS       2010-T102
2010 TZ54  Amor    20   0.304   2.29  0.45   9.5  19.0  Spacewatch      2010-T101
2010 TY54  Amor    19   0.218   2.40  0.50   8.7  21.3  Mount Lemmon    2010-T100
2010 TX54  Apollo  19   0.107   1.45  0.34  27.1  20.9  Catalina        2010-T89
2010 TW54  Apollo  18   0.0013  1.05  0.24   2.7  27.6  Mount Lemmon    2010-T88
2010 TV54  Apollo  20   0.007   1.93  0.62   6.2  25.5  Mount Lemmon    2010-T87
2010 TU54  Amor    21   0.263   1.57  0.33  27.4  21.3  PANSTARRS       2010-T86
2010 TS54  Amor    21   0.130   1.46  0.23  15.3  24.5  Mount Lemmon    2010-T85
2010 TR54  Amor    20   0.072   1.70  0.37   4.4  24.5  Mount Lemmon    2010-T84
2010 RS180 Amor    19   0.110   1.88  0.41   2.9  20.5  La Sagra        2010-T109

Comet       Type       T        q     a     e      i  Mag  Period        MPEC 
P/2010 U2 (Hill)
            JFC   2010 11 09  2.55  4.29  0.40   16.9  18   8.88 yrs     2010-U19
P/2010 U1 (Boattini)
            JFC   2010 05 15  4.88  6.66  0.27    8.2  19  17.2  yrs     2010-U18
P/2010 T2 (PANSTARRS)
            JFC   2011 07 29  3.73  5.59  0.33    8.1  21  13.2  yrs     2010-U07

Type
Aten -  Earth crossing with semi-major axis (avg distance from Sun) < 1 AU
Apollo - Earth crossing with semi-major axis (avg distance from Sun) > 1 AU
Amor - non-Earth crossing with perihelion distance < 1.3 AU
JFC - Jupiter family comet
HFC - Halley family comet
LPC - Long-period comet
MBC - Main belt comet
ECC - Suspected extinct or dormant (or just unrecognized) comet
T - Date of Perihelion
MOID - Minimum Orbit Intercept Distance, minimum distance between asteroid and Earth's orbit
a - semi-major axis, average distance from Sun in AU (1 AU = 93 million miles)
e - eccentricity
i - inclination
H - absolute magnitude
Mag - magnitude at discovery
Discoverer - survey or person who discovered the object
MPEC - Minor Planet Electronic Circular, the discovery announcement
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