November 7, 2009 17 Comments
This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of November 2009. Jupiter continues its reign as not only king of the planets but king of the evening sky. November also brings the Leonids which may put on a good show for some observers this year.
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.
Jupiter - Jupiter continues to dominate the evening sky. At magnitude -2.4, Jupiter is ~10 times brighter than the brightest stars in the sky this month. Of all the planets, only Venus, and on very rare occasions Mars, are brighter.
Jupiter is located high in the southern sky by the end of dusk for easy observation. As has been the case all year, it is slowly moving through the southern constellation of Capricornus.
Nov 23 - Moon passes 3° from Jupiter
Neptune – For those with a telescope or binoculars and a dark sky, Neptune is located within 1/2 to 3/4 degrees of Jupiter. Jupiter will be a bright magnitude -2.4 while Neptune will be a faint +7.9. Even Jupiter’s 4 large Galilean moons are about a dozen times brighter than Neptune even though they are much smaller. The big reason for the faintness of Neptune is its distance from both the Earth and Sun. It is roughly 6 times further away from us and the Sun as Jupiter. The distance also explains its apparent small size of 2.3″. A good sized telescope will be required to see Neptune as anything other than a faint star.
Uranus – Uranus is located in western Pisces and is bright enough to be seen in small binoculars at magnitude +5.8 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.5″ across).
Mars – Mars can be seen rising in the eastern sky late in the evening (~11 pm at the start of the month and ~9 pm at the end of the month). Mars is rapidly brightening and will reach magnitude 0.0 by the end of the month, matching that of many of the brightest stars visible in the morning sky. Mars will continue to brighten as it approaches its opposition on Jan 29 of next year. This month Mars marches through eastern half of the constellation of Cancer.
Nov 9 – Moon passes close (3°) to Mars
Venus - Venus rises an hour before dawn. When it is visible it is easily the brightest “star” in the sky. It was at its highest in the morning sky back in August and is continuing its slow crawl lower. It is located just above the horizon in the ESE sky right before the start of dawn. For binocular and telescope users, Venus will appear nearly full and is much smaller than it appeared this spring (now 11″ across versus 50″ last spring).
Nov 15 – Moon passes 6° from Venus
Mercury - Mercury starts the month behind the Sun with superior conjunction occurring on November 5. For the rest of the month, Mercury slowly pulls away from the Sun into the evening sky. Southern hemisphere observers will be able to catch a glimpse of Mercury low in the WSW sky during evening twilight. Northern observers will have to wait till December for their chance at seeing Mercury again.
Nov 5 – Mercury at superior conjunction
Saturn – Saturn is easy to observe during the last few hours of the night. Located in Virgo at magnitude +1.0, Virgo only rises right before the start of dawn. Telescope users should note that Saturn’s rings are still close to edge-on.
Nov 12 – Moon and Saturn within 7° of each other
November hosts the sometimes great Leonids. In addition, the background rate of meteors is near an annual high. 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 November, 12 or so Sporadic meteors can be observed per hour from a dark moonless sky.
Major Meteor Showers
The Leonids have produced some of the most spectacular meteor displays in history. Rates as high as ~70,000 meteors per hour (that’s ~20 meteors per second) were seen in 1833 and 1966. Every ~33 years, the parent comet of the Leonids, Comet Tempel-Tuttle, returns to the vicinity of the Earth. For a few years after Tempel-Tuttle’s last perihelion in 1998, the Leonids produced enhanced rates of meteors as high as 100s to 1000s of meteors per hour.
What will 2009 bring? In a normal year, the Leonids produce maximum rates of ~10-15 meteors per hour. This year there are a number of predictions of enhanced activity.
J. Vaubaillon presents his predictions for this year’s Leonids at the website of the L’Institut de Mécanique céleste et de calcul des éphémérides (IMCCE). The Earth will encounter 4 dense dust trails produced by the Leonid parent comet. On November 17 at ~21:43 UT (or half an hour to an hour later), the Earth will encounter a trail produced in 1466 which may produce as many as ~115 meteors per hour from a dark site. At nearly the same time, November 17 at 21:50 UT, the 1533 trail may produce 80 meteors per hour. Combined the 2 trails may (may being the important word) produce ~200 meteors per hour. A display this strong would not be considered a “storm” but would be better than the Perseids or Geminids at their best by nearly a factor of 2. The predicted times favor observers in central Asia. Unfortunately for those of us in the US, we will miss out.
Two weaker and much more uncertain trails will be observable from the Western hemisphere. On November 17 at ~7:27 UT, the 1567 trail may produce 25 meteors per hour. Since this is in addition to the usual background rate of Leonids may result in total rates of 35-50 per hour which is comparable to last month’s Orionids. Also on November 18 at ~3:29 UT, the very old 1102 trail may enhance activity by 10-50 meteors per hour.
What does this mean? Most of us, especially in the United States, will only see the “normal” maximum on the morning of November 17 with hopefully an extra dozen or two meteors per hour from the 1567 trail. For those located in central Asia, a very good shower may be visible. The Leonids are best observed in the hours before sunrise. They will appear to radiate from the western part of the constellation of Leo.
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.
Northern and Southern Taurids (NTA/STA)
The Taurids never produce more than ~5 meteors per hour. They make up for their low rates by being active for over two months and by producing many bright fireballs. Their fireballs are more apparent to the average observer because, unlike most meteor showers, the Taurids are observable all night long rather than just in the morning. There is a chance that the Taurids will produce a higher number of fireballs this year than usual. There is a good chance that most fireballs being reported this month will be Taurids. They are active for the entire month of November with the northern branch (NTA) peaking around November 14. Though named after the constellation of Taurus, theTaurids radiate from a point between the constellations of Taurus and Aries this month.
The Taurids are produced by Comet 2P/Encke. Encke is an enigmatic object with the shortest period for any known comet at 3.3 years. First observed in 1786, it has been observed over ~60 orbits and has been seen every year since 1993.
Additional information on these showers and other minor showers not included here can be found at the following sites: Robert Lunsford’s Meteor Activity Outlook, Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.
Naked Eye Comets (V < 6.0)
Binocular Comets (V = 6.0 – 8.0)
Small Telescope Comets (V = 8.0 – 10.0)
P/Howell is an evening comet and currently the brightest in the sky. Howell is a short-period comet and takes only 5.49 years to orbit the Sun. Ellen Howell was a student at Caltech when she found the comet on photographic plates taken on 1981 August 29 with the 48″ Palomar schmidt.
In 1981 the comet was on an orbit that never brought it closer to the Sun than 1.62 AU (perihelion distance). As a result, it never got very bright. A relatively close approach to Jupiter in 1990 changed its perihelion distance to 1.40 AU. Further perturbations by Jupiter have decreased its perihelion distance to 1.36 AU. The closer perihelion distance allows the comet to get bright enough for small backyard telescopes. In addition, the comet seems to be running about ~2 magnitude brighter than usual. No obvious reason for the additional brightening has been observed yet.
This year perihelion occurred on Oct 12 so the comet is currently moving away from the Sun and should be fading. A day after perihelion I observed the comet from Tucson with a 12″ dobsonian. The comet was very difficult to observe from the city. At the time, I estimated its brightness at magnitude 8.5. The comet should be a little fainter (from 8.8 to 9.5) this month. The comet is located low in the southwest sky after dusk and will spend most of the month in Sagittarius. At mid-month P/Howell will be 1.41 AU from the Sun and 1.79 AU from Earth.
Comet C/2006 W3 (Christensen)
This comet was discovered nearly 3 years ago on 2006 November 18 by Eric Christensen of the Catalina Sky Survey north of Tucson. At the time the comet was located 8.7 AU from the Sun which is nearly the distance of Saturn.
The comet reached perihelion at a rather distant 3.12 AU from the Sun on 2009 July 6. Because of its large perihelion distance, the comet will only slowly move away from the Sun and, though it will slowly fade, it should remain bright enough to be seen in modest sized backyard telescopes this month.
At mid-month, the comet is 3.37 AU from the Sun and 3.82 AU from Earth. Though observed as bright as magnitude ~8.2 it is now around magnitude 9.5 to 10.0. It is moving southeast while paralleling the summer Milky Way. This month the comet can be found in southern Aquila near the Sagittarius and is well placed for evening observing. This will probably be the last month that this comet will be observable in small scopes.
217P/LINEAR is also a short-period comet though it takes a little longer than Howell to circle the Sun, 7.83 years versus 5.49 years. P/LINEAR also comes closer to the Sun with perihelion at 1.22 AU from the Sun. The comet is already a month past perihelion which occurred on Sept 8.
P/LINEAR was first observed by the Lincoln Near Earth Asteroid Research (LINEAR) survey on 2001 June 21 though it wasn’t until 2001 July 11 that it was recognized as a comet. The 2009 apparition is the first return since the discovery apparition.
Though P/LINEAR and P/Howell have similar perihelion distances, LINEAR is a much fainter (or less active) comet. While Howell is ~9th magnitude at a rather distant 1.65 AU from Earth, P/LINEAR is a little fainter at magnitude ~10.0 though it is much closer (0.61 AU from Earth). This may be the last time to see P/LINEAR in small backyard telescopes until its 2048 return when it will pass within 0.40 AU of Earth. All the returns between 2009 and 2048 will be more distant.
I was able to observe 217P/LINEAR with 30×125 binoculars on the morning of Sept 25. In order to see the comet I had to drive out to a dark site. The comet was a rather nondescript smudge about 1.5′ across and with a brightness of magnitude 10.1. On Oct 16, I dragged my 12″ dob to a dark site. The comet was easy to observe with a nice short 0.08° long tail. At that time, the estimated brightness was magnitude 9.9.
This month the comet will be visible in the morning sky in the faint Milky Way constellation of Monoceros. It should remain at magnitude ~10 or a little fainter for the entire month. At mid-month the comet will be 1.49 AU from the Sun and 0.64 AU from Earth.
Comet C/2007 Q3 (Siding Spring)
This long-period was first seen on 2007 August 25 by Donna Barton of the Siding Spring Survey in Australia. This past Oct. 7th the comet reached a rather distant perihelion at 2.25 AU from the Sun. Unfortunately, the comet and Earth are located on opposite sides of the Sun so the comet is rather far from Earth. Still the comet is observable before the start of dawn as a ~9.0 to 9.5 magnitude comet near the Leo/Virgo border. At mid-month the comet is 2.30 AU from the Sun and 2.71 AU from Earth.
A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).
Binocular and Small Telescope Asteroids (V < 9.0)
Juno was the 3rd asteroid to be discovered after (1) Ceres and (2) Pallas. It was found by German astronomer Karl Harding on September 1, 1804. With dimensions of 320×267×200 km (192 x 160 x 120 miles) Juno ranks as the 10th largest asteroid in the Main Belt though it is the 2nd largest stony S-type asteroid.
This month it will be moving slowly southwestward in Aquarius. Peak brightness occurred at opposition on Sept. 22 when Juno was as bright as magnitude 7.6. In November it will fade from magnitude 8.4 to 8.9. Twenty degrees or so to the east of Juno is another bright asteroid, (18) Melpomene which is described in its own section.
About 25 degrees to the east of (3) Juno lies another nice asteroid target for small telescopes. (18) Melpomene is located in the constellation of Cetus and is roughly the same brightness as Juno, in November it will fade from magnitude 8.3 to 9.0.
Melpomene is another stoney S-type asteroid and similar to Iris was also discovered by John Russel Hind. Found in 1852, it is his 5th of 10 asteroid discoveries.
Though not as large as Ceres, Vesta is more reflective making it the brightest asteroid in the Main Belt. Vesta is 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 is similar in size to Pallas with dimensions of 347x336x275 miles or 578×560×458 km. Vesta will also be visited by NASA’s Dawn spacecraft which will arrive in 2010.
Vesta is once again observable in the morning sky before the start of dawn. It is brightening from magnitude 8.1 to 7.7 as it travels eastward just north of Regulus in Leo.