Every ~5.3 years, comet 96P/Machholz makes a close and personal swing around the Sun. At a distance of 0.12 AU, comet Machholz comes within 11 million miles (18 million km). That is 8 times closer to the Sun than the Earth and even 2.5 times closer than the innermost planet Mercury.
Though the comet can become very bright at perihelion, its close proximity to the Sun makes it all but impossible to observe at that time. Luckily we have a number of spacecraft observing the Sun which can also be used to observe the comet. One such spacecraft, the joint ESA/NASA Solar and Heliospheric Observatory (SOHO) is currently picking up the comet. The image below is the latest image from the LASCO instruments on the spacecraft. [Update: 96P has now moved out of the SOHO LASCO field-of-view.As of 10 am (Tucson time) on the 13th, the comet is visible to the lower right of the Sun. A short tail is also visible trailing away from the Sun.As of 10 am (Tucson time) on the 14th, the comet is visible just to the upper right of the center obscuration.As of 10 am (Tucson time) on the 15th, the comet is visible halfway between the center and the top of the image.As of 8 am (Tucson time) on the 16th, 96P is visible near the edge of the field at the 11 o’clock position.Since the comet is about as close to the Sun as it gets, it is also visible in the higher resolution LASCO C2 field. A real-time C2 image is located below under the C3 image. In the C2 image the comet can be seen near the upper right corner though it will move out of the field in a few hours. The comet is no longer visible in the C2 field.] Additional SOHO images can be found here.
Perihelion occurred on July 14.78 UT (or roughly 11:40 am Tucson time on the 14th, that’s 11:40 am PDT, 12:40 pm MDT, 1:40 pm CDT, 2:40 pm EDT). By the end of July, the comet will be visible in the evening sky as a faint and difficult 9-10th magnitude object for telescope observers.
The sample return capsule of the Hayabusa spacecraft has successfully returned to Earth. The video below was taken by a NASA DC-8 aircraft specifically equipped to observe the event.
The video shows the disintegration of the main Hayabusa spacecraft. The small consistent “meteor” to the lower right of the disintegrating spacecraft is the sample return capsule. The original plan was for the main spacecraft to release the capsule for Earth return and then change its trajectory in order to miss the Earth. That way the main spacecraft would fly past the Earth and be able to visit other targets. Due to the many propulsion problems it could not conduct the necessary maneuvers and, instead, re-entered the Earth’s atmosphere right behind the sample return capsule. Since it did not have a protective heat shield like the capsule it did not survive passage through the atmosphere.
Hopefully we’ll hear soon whether any asteroid samples have been recovered.
At 1400 hours UT on Sunday June 13 a brilliant fireball will appear over Australia. Unlike most fireballs this one won’t be due to a small asteroid but a returning man-made spacecraft. The Japanese Hayabusa (originally called MUSES-C for Mu Space Engineering Spacecraft C) is returning home after a harrowing 7 year mission to a small near-Earth asteroid and back. Harrowing in that almost anything that could go wrong did go wrong. Yet, if all goes well Hayabusa will be the first spacecraft to return samples from an asteroid.
[NOTE: A team from NASA will observe and study the resulting fireball from a NASA research DC-8 aircraft. The airborne team will attempt to broadcast video of the even live. Live video will be shown at 13:45-13:55 UT (9:45-9:55 am EDT).]
Launched in May of 2003, Hayabusa spent just over 2 years traveling to the half-km in diameter Earth-crossing asteroid (25143) Itokawa. In November of 2005 two sample attempts were made. The plan was for Hayabusa to hover a few meters above the asteroid’s surface, fire a small projectile into the surface, and collect any material that was thrown upwards. Due to spacecraft hardware and software control failures mission operators are unsure if any samples were collected. In fact, no one is completely sure what happened when Hayabusa reached the asteroid’s surface due to a loss of contact.
Due to the great work of the mission team, the hobbled spacecraft was coaxed back to Earth in spite of losing its reaction wheels, reaction control system (fine thrusters), and some of its ion thrusters (main propulsion). Regardless of whether Hayabusa successfully lands in Australia on Sunday or whether or not it contains any samples from Itokawa, the mission was highly successful and produced some great data on a small near-Earth asteroid.
This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of June 2010.
June 2010 Highlights
* Venus, Mars and Saturn close in on each other in the evening sky
* Comet 2009 R1 (McNaught) reaches naked eye brightness in the morning sky
* Jupiter passes close to Uranus
* Asteroid (1) Ceres at opposition on the 19th and is an easy binocular object
* Partial Lunar Eclipse for the Far East and most of North/South America on the 26th
* Japanese Hayabusa spacecraft to return samples from asteroid Itokawa on the 13th
* EPOXI (spacecraft formally known as Deep Impact) flys past Earth on the 27th
Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment and I’ll post them on the blog.
Hayabusa – On the June 13th, the JapaneseHayabusa spacecraft is scheduled to return to Earth. Tucked away in its sample return capsule may be a few grams of regolith (asteroid soil) from the small Near-Earth asteroid (25143) Itokawa). Launched in 2003, Hayabusa spent a few months in late 2005 studying Itokawa. Though the plan was to retrieve samples of the asteroid for return to Earth, the mission was plagued with many difficulties. As a result, mission operators are unsure if any samples were picked up. Even whether or not the spacecraft can successful hit it target and land in Australia is in doubt. Regardless, the spacecraft and its sample return capsule will be coming back to Earth on the 13th.
The main comet event of 2010 will be periodic comet 103P/Hartley 2. Not only will the comet become a nice naked eye object this fall, but a re-used NASA spacecraft will encounter the comet. EPOXI has gone through quite a few name changes in its time. Originally Deep Impact it was launched in January 2005. In July 2005, it released a small package which impacted the surface of periodic comet 9P/Tempel 1. The impact allowed scientists an opportunity to study the interior of a comet. After the conclusion of its primary mission, NASA agreed to fund 2 experiments that utilized the spacecraft. One of its cameras was used to study planets studying other stars (an experiment called EPOCh, for Extrsolar Planet Observation and Charaterization). Also it will fly-by the aforementioned comet Hartley 2 (an experiment called DIXI for Deep Impact eXtended Investigation). Eventually the names were merged into EPOXI but really we are just talking about the old Deep Impact spacecraft.
On the 27th, EPOXI will fly-by the Earth setting up an encounter of Hartley 2 on November 4th.
Planets (and Moon)
Moon – The Moon will experience a Partial Lunar Eclipse on the night of June 25/26. At its best, a little over 53% of the Moon will be in umbral (darkest) eclipse. For the best info on this eclipse go to NASA’s Eclipse Website.
Venus – Venus is the brightest “star” visible in the early evening. Low in the west it sets about 2.5 hours after the Sun. From now till July/August it will ride as high as it’ll get for northern observers. In fact, this is not a great evening apparition for Venus. On the other hand, it is a great apparition for observers south of the Equator. For them, Venus will continue to climb higher till late August. Regardless, of where you are located it will be hard to miss brilliant -4 magnitude Venus in the west an hour or 2 after sunset.
June 11 - Venus in line with bright stars Castor and Pollux
June 15 - Moon passes within 4° of Venus
June 20 - Venus passes the center of the Beehive star cluster
Mars – Mars moves rapidly through the constellation of Leo this month. Though fading from magnitude +1.1 to +1.3 it is still an obvious red beacon to the southwest of overhead right after sundown. It’s brightness is comparable to that of the other bright stars. Watch Mars pass within 0.8° of the bright star Regulus on the 7th. Mars will be magnitude +1.2 on that date and just slightly brighter than Regulus at magnitude +1.4. By the end of the month, Mars is located within 16° of Saturn. The two will be closest at the end of July, and will be joined by Venus in early August.
June 7 - Mars passes 0.8° from the 1st mag star Regulus
June 17 - Moon passes within 6° of Mars
Saturn – This month Saturn is visible in the south during the early evening hours. It will slowly fade from magnitude +1.0 to +1.1 making it slightly brighter than Mars. Telescope users should note that Saturn’s rings are still within a few degrees of edge-on.
June 19 - Moon passes within 8° of Saturn
Jupiter and Uranus – Jupiter once again returns to sight as a brilliant star low in the east-southeast before dawn. The magnitude -2.4 planet will get brighter and better place for observing over the next few months. Last year Jupiter made a series of close approaches to Neptune. This year Jupiter will do the same for Uranus. On June 6th, Jupiter will make it’s first closes approach to Uranus at a small distance of 0.44°.
June 6 - Moon passes within 7° of Jupiter
June 8 - Jupiter passes within 0.5° of Uranus
Mercury -Mercury is in the middle of a morning apparition at the start of the month. This morning apparition will not be good for northern observers though it is excellent for southern observers. By mid-month, Mercury will have fallen back into the glare of the Sun.
June 11 - Moon passes within 9° of Mercury
June starts to see an increase in meteor activity after a few months of low activity. 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 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 June, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.
Major Meteor Showers
No major showers are active 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.
Comet C/2009 R1 (McNaught) will be a bright binocular comet and probably even a faint naked eye comet for observers under dark skies. Observations made over the past few weeks shows this comet to be rapidly brightening. By the start of June, the comet should be around magnitude 6.5 to 7.0. By mid-month, it will have brightened to magnitude 5.0 and maybe even 4.0. By the end of the month, it will be a bright magnitude 4.0 and perhaps brighter. The lightcurve below shows 3 possible brightness trends that the comet could follow. Though the red curve which shows a peak brightness of magnitude 2 would be nice it is most likely the comet will follow one of the fainter curves and peak at magnitude ~4.
The comet is a morning object and is only visible for an hour or so before the start of dawn. By the end of the month the comet can also be glimpsed in the evening. As the month progresses the comet will become harder to see as it moves closer to the Sun. Observers will need a clear NE (or NW in the evening later in the month) horizon to see the comet. Fourth magnitude is bright enough to be seen with the naked eye under dark conditions. Unfortunately the majority of us live under bright, murky skies so binoculars will be required to see the comet for most people. The fact that the comet will set will twilight is still bright surely doesn’t help either. Currently the comet is located in Andromeda but it will quickly move through that constellation as well as Perseus and Auriga.
Still inbound, perihelion will occur on July 2nd of this year at a relatively small distance of 0.41 AU from the Sun. This month it will be 0.88 AU from the Sun and 1.26 AU from Earth on June 1st, 0.61 AU from the Sun and 1.14 AU from Earth on the 15th, and 0.41 AU from the Sun and 1.26 AU from Earth on the 30th.
The 2nd ‘Comet McNaught’ is Comet C/2009 K5 (McNaught). It was discovered on May 27, 2009 deep in the southern sky. Similar to C/2009 R1, this comet was also found with the Uppsala schmidt at around magnitude 17.
With perihelion on April 30 of this year at a distance of 1.42 AU from the Sun, C/2009 K5 is still bright enough to be seen in small backyard telescopes from dark sites. At mid-month it will be located 1.57 AU from the Sun and 2.05 AU from Earth.
Observations over the past 2 months show the comet to be around magnitude 8.0 to 8.5. With the comet in full retreat from the Sun and Earth, it should fade from here on out. The comet will start the month between 8.0 and 8.5 but should fade to around 9.0 by the end of the month. Due to its located in the far northern constellation of Camelopardalis, the comet can be seen at all hours of the night from northern latitudes. It is best in the evening right after the end of twilight.
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 next year 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 starts the month at magnitude 7.7 and steadily fades to mag 7.9. A pair of binoculars will allow you to see Vesta among the stars of Leo.
Ceres is the biggest asteroid in the Main Belt with a diameter of 585 miles or 975 km. It is so big that it is now considered a Dwarf Planet. Classified as a carbonaceous (carbon-rich) Cg-type asteroid, there are suggestions that it may be rich in volatile material such as water. Some even propose that an ocean exists below its surface. Ceres is the other target of NASA’s Dawn spacecraft which is scheduled to visit it in 2015.
This month Ceres will be at opposition and brightest. The asteroid will start the month at magnitude 7.5, brighten to magnitude 7.1 at opposition of June 19, and then fade to magnitude 7.4 by the end of the month. All month long it will be retrograding on the border of Sagittarius and Ophiuchus.
Observers from South Africa to Europe witnessed a unique space event last Sunday evening. What appeared to be 1 or 2 “comet”-like objects surrounded by expanding “smoke” rings was in fact a fuel dump from a recently launched weather satellite.
Fuel and water dumps from spacecraft and rockets happen quite often. These types of events have been seen throughout the world. Sometimes the dumps appear as slowly expanding clouds. On one occasion the dump took on an almost “angelic” appearance.
At 16:12 GMT on October 18 an Atlas-5(401) rocket was launched from Vandenberg Air Force base in California. The rocket carried the American DMSP F18 military weather satellite into a near-polar (sun synchronous) orbit. Though this satellite is operated by the US military, there is nothing secret about it and it is very similar to civilian weather satellites. A Centaur upper stage was used to place the satellite in its operational orbit. It is this upper stage that produced the light show seen by African and European observers.
After their mission is over, most upper stages dump any remaining fuel overboard, a procedure known as a fuel dump. This is done to prevent the remaining fuel from eventually causing an explosion which would litter space with hazardous (for other satellites and astronauts) debris. The DMSP F18 launch was a little different. The Atlas-5(401) rocket and Centaur upper stage combination was more than capable of lifting the DMSP F18 to orbit. As a result, more fuel than usual remained in the upper stage. The excess fuel allowed the operators of the Centaur to conduct a number of tests, including what is known as a “pulsed chilldown mode”. These tests resulted in the periodic release of fuel resulting in the observed series of quickly expanding concentric rings. The tests started as the upper stage was traveling over southern Africa. By the time it was over Europe the tests were over though the ring(s) were still faintly visible. European observers did witness the Centaur conducting a burn which eventually placed the upper stage on a heliocentric orbit around the Sun.
After a few days of clouds, the sky was once again clear over southern AZ. Still, rates are probably lower than they should be due to a bright Moon shining directly overhead during the prime meteor watching hours.
This week should see steadily increasing meteor rates due to the rise of the Orionids (towards an Oct 21/22 peak) and a less obtrusive Moon.
I was up this morning watching the Moon for evidence of NASA’s LCROSS impact experiment. Though the seeing was rather poor, I was able to get some good quality video. Nevertheless, I didn’t see anything from the impact. Then again this was the case with professional telescopes many times larger than mine.
Bob’s notes for 10/8:
“Much like last night, a bright moon and periodic clouds limited the number of meteors recorded tonight. It was interesting to note the Southern Taurids equaled the sporadic rate last night.”
.. for 10/9:
“More or the same with clouds and the moon…”
Obs Date (UT) TotTime TOT SPO NTA STA ORI DAU DRA EPC
TUS 2009-10-09 10h 36m 35 19 3 1 4 2 2 0
SDG 2009-10-09 09h 56m 24 17 - 7 0 - 0 0
TUS 2009-10-08 00h 00m Clouds all night
SDG 2009-10-08 08h 56m 18 8 - 8 2 - 0 0
TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
NTA – Northern Taurids (includes Antihelions)
STA – Southern Taurids (includes Antihelions)
ORI – Orionids
DAU – Delta Aurigids
DRA – October Draconids (Giacobinids)
EPC – September Epsilon Piscids