In The Sky This Month – January 2011

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

January 2011 Highlights
* Quadrantids Meteor Shower peaks on Jan 4
* Jupiter rules the evening sky, while...
* Venus dominates the morning sky with ...
* Mercury also in the midst of a good morning apparition

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.

Jan 1 - Moon 3° from bright star Antares
Jan 2 - Moon 4° from Mercury
Jan 4 - New Moon
Jan 10 - Moon 6° from Jupiter and Uranus
Jan 12 - First Quarter Moon
Jan 15 - Moon 1.3° from Pleiades
Jan 16 - Moon 8° from bright star Aldebaran
Jan 19 - Full Moon 9° from bright star Pollux
Jan 20 - Moon 4° from Beehive Cluster
Jan 21 - Moon 5° from bright star Regulus
Jan 25 - Moon 8° from Saturn and 3° from bright star Spica
Jan 26 - Third Quarter Moon
Jan 29 - Moon 3° from bright star Antares
Jan 30 - Moon 4° from Venus

Jupiter (and Uranus, too…) – The ‘King of the Planets’ continues his reign as the uncontested ‘King of the Evening Sky’ though fading from magnitude -2.3 to -2.2, nothing but the Moon rivals it in brightness. Located on the Pisces/Aquarius border, Jupiter is easy to find in the south as it gets dark. Jupiter then spends the rest of the evening getting lower in the southwest sky.

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 close to Uranus all month long. On Jan 4 the two are 0.5° apart.

Jan 4 - Jupiter and Uranus within 0.5° of each other
Jan 10 - Moon within 6-7° of Jupiter and Uranus

Saturn – Saturn rises during the middle of the night. Located in Virgo, the ringed planet is a close match in brightness (mag +0.7) to Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 8-9° of Spica.

Jan 25 - Moon within 8° of 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 almost 3 hours before the Sun in the eastern sky. 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’.

Jan 8 - Venus at Greatest Elongation West
Jan 17 - Venus within 8° of bright star Antares
Jan 30 - Moon within 3.5° of Venus

Mercury – Mercury is in the middle of a good morning apparition all month long.

Jan 2 - Moon within 4° of Mercury
Jan 9 - Greatest Elongation West

Mars – Too close to the Sun for observation.

Meteors

Meteor activity starts to plummet in January. 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

Quadrantids (QUA) [Max Date = Jan 4, Max Rate = ~60-150 per hour under dark skies]

The Quadrantids are the best shower that you’ve probably never heard of. It’s bad enough that this shower peaks in the middle of winter in the northern hemisphere, but it is also named after a long defunct constellation. When first identified in the early 1800s, the meteors were observed to radiate from the small faint constellation of Quadrans Muralis (the Mural Quadrant). Unfortunately, the constellation didn’t make the cut when the official list of 80 constellations was set in 1930. Today, Quadrans Muralis and the radiant of the Quadrantids can be found on the northern reaches of the constellation Bootes.

Another strike against observing the Quadrantids is their short duration. Most showers, like the Perseids and Orionids, produce high rates of meteors for a few days near their maximum. The Quadrantids are only highly active for 12-24 hours. As a result, the shower can be missed if the peak does not coincide with your early morning observing.

The peak time for this shower is always uncertain on the order of half a day or so and the IMO prediction calls for a peak some time between 21:00 UT on Jan 3 and 6:00 UT on Jan 4. This well placed for observers in Europe. Here in the US activity during the prime early morning hours should be rapidly tailing off.

Back in 2009 this shower put on a great show with the peak well observed from the US. Peak rates that year reached a ZHR of ~150-160. But in 2008, rates “only” reached into the 80s. With the Moon near New the sky will be dark. Who knows what we’ll get this year so we’ll just have to brave the cold and see.

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)

None

Small Telescope Comets (V = 8.0 – 10.0)

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 January around magnitude 8-9 and should steadily fade to around magnitude 9-10 by the end of the month.

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 8.3, brightens to 7.9 at opposition on the 24th and then fades to 8.1 at 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 Ceres from Heavens Above.