In the Transient Sky – January 2013
January 2, 2013 4 Comments
January 2013 Highlights * Quadrantid meteor shower peaks on the morning of January 3 * Jupiter is bright in the eastern evening sky * Jupiter and the Moon pair up on the evening of January 21 * Four comets may be brighter than 10th magnitude * Comet C/2011 L4 (Panstarrs) approaches naked eye brightness (though it will only be visible from the southern hemisphere and will be located near the 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 <email@example.com>.
Mars – One needs a very clear southeast horizon to catch Mars in the early evening. Glowing at magnitude +1.2 Mars is currently not as bright as other planets. But it is traveling through a patch of sky with few bright stars so it is rather apparent as the brightest, reddest, “star” in that part of the sky. It spends most of the month against the stars of Capricornus. The Moon passes near Mars on the evening of the 12th.
Jupiter – Jupiter is now a month past opposition. It spends the month slowly retrograding just north of the stars of the Hyades cluster in Taurus as it fades from magnitude -2.7 to -2.5. It is already well up in the northeast at sundown. On the evening of January 21, the Moon and Jupiter make a beautiful pair.
Saturn – Saturn is an early morning object rising around 3:00 am at the start of the month. By the end of the month, Saturn rises 2 hours earlier. All month Saturn glows at magnitude +0.6 between Virgo and Libra. The Moon passes close to Saturn on the mornings of the 6th and 7th.
Venus – Venus is approaching its next superior conjunction (when it passes by the far side of the Sun from Earth) which takes place on March 28 and enters the evening sky. This month Venus is still a morning object though it can only be seen within an hour of sunrise. On the morning of January 10th, a very thin crescent Moon is located near Venus. This will be the last month to easily see Venus until the Summer when it will reappear in the western Evening sky.
Mercury – Mercury is too close to the Sun for easy observation this month. It will be observable next month in the evening sky.
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. Meteor activity is still near an annual maximum this month.
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 early January mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky. The rate drops as the month progresses.
Major Meteor Showers
Quadrantids (QUA) [Max Date = January 3, Max ZHR = ~60+ per hour]
This year’s Quadrantids will peak during the morning of January 3rd. Unfortunately, a very bright Moon will be located high in the southern sky during the prime morning meteor watching hours.
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 at 13:30 UT on Jan 3 though this time could be off be 12 hours or more. Observers in Europe and the Americas will be well placed for seeing this year’s peak. Unfortunately observers south of the Equator will not see much from the Quadrantids.
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, 2011 and 2012, rates “only” reached into the 80s. The waning gibbous Moon will be a problem as it rises around 10:45 pm and is up for the rest of the night. With the radiant only getting high enough for easy observing after 3 am the Moon will be a hindrance. Meteor watchers should try to look at a part of the sky that does not include the Moon in your field-of-view.
Minor Meteor Showers
Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.
Naked Eye Comets (V < 6.0)
C/2011 L4 (PANSTARRS)
This comet is forecast to reach a brilliant magnitude ~-1 near its March 10th perihelion. At the time the comet only be 0.30 AU from the Sun. As bright as this is, the comet will be poorly situated close to the horizon. Still it will be a very nice binocular or small telescope sight. The comet was first seen by the Hawaiian based PanSTARRS asteroid survey on June 6, 2011 at a large distance of 7.9 AU from the Sun.
This month, the comet starts at a distance of 1.6 from the Sun though that distance will drop to 1.0 AU at the end of the month. A few recent observations place it at magnitude ~8.3. If it continues to brighten as expected it may even break 6th magnitude by the end of the month. The comet will only be observable from the Southern Hemisphere this month as it slowly moves away from the Sun against the stars of Scorpius and Corona Australis. Northern observers will have to wait till late March when the comet should be a naked eye object.
Finder charts can be found at Chasing Comets.
Ephemeris for C/2011 L4 (Panstarrs) Date RA DEC Delta r Elong V 2012 Jan 01 17h 17m -39d 17' 2.427 1.589 24 8.3 2012 Jan 11 17h 46m -41d 23' 2.185 1.412 29 7.6 2012 Jan 21 18h 23m -43d 31' 1.932 1.226 32 6.7 2012 Jan 31 19h 14m -45d 15' 1.674 1.030 34 5.6 RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU r = distance from the Sun in AU, Elong = elongation from Sun in degrees V = Visual magnitude
Binocular Comets (V = 6.0 – 8.0)
C/2012 F6 (Lemmon)
Everyone was expecting C/2011 L4 (PANSTARRS) and C/2012 S1 (ISON) to be the two naked eye comets of 2013. No one was expecting C/2012 F6 (Lemmon) to be vying for the status of naked eye comet when it was discovered by Alex Gibbs of the Mount Lemmon survey back on March 23, 2012. At that time the comet was a faint 20th-21st magnitude and 5.0 AU from the Sun. It also appeared to be an intrinsically faint comet. So faint in fact that I though it had a good chance of disintegrating near perihelion. Instead the comet has brightened at a rapid rate. If this brightening trend continues the comet may be a faint naked eye object this February through May. Perihelion will occur on March 24, 2013 at a distance of 0.73 AU from the Sun.
Over the past few days visual observers have estimated the comet at magnitude ~8.5. I was able to observe the comet on Christmas morning at magnitude 9.6. Since there was cirrus around my estimate is probably an underestimate. The comet was rather big (6′ across) and diffuse with no sign of a tail in my 30×125 binoculars.
The comet is already too far south for most northern observers and the comet will continue to travel deeper into the southern sky this month. As a result, this comet will only be visible to southern observers till May.
The comet starts the month around magnitude 8.5 and will continue to rapidly brighten all month. By the end of the month the comet may be as bright as magnitude 6.0. It will be traveling south from Hydra through Centaurus, Crux, and Musca.
Finder charts can be found at Chasing Comets.
Ephemeris for C/2012 F6 (Lemmon) Date RA DEC Delta r Elong V 2012 Jan 01 12h 08m -36d 30' 1.453 1.660 83 8.6 2012 Jan 11 12h 18m -47d 42' 1.243 1.518 85 7.8 2012 Jan 21 12h 33m -62d 08' 1.084 1.376 83 7.0 2012 Jan 31 13h 19m -79d 22' 0.997 1.235 77 6.2 RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU r = distance from the Sun in AU, Elong = elongation from Sun in degrees V = Visual magnitude
Small Telescope Comets (V = 8.0 – 10.0)
C/2012 K5 (LINEAR)
This is a long-period comet discovered by the LINEAR near-Earth asteroid survey program on May 25, 2012. At the time the comet was around magnitude 17-18. Though it passed through perihelion on Nov. 28 at a distance of 1.14 AU, the comet reached its brightest last month as it rapidly approached Earth. Close approach occurred at the very end of December at a distance of 0.29 AU (27 million miles or 44 million km).
Recent visual observations place the comet around magnitude ~8.6 at the end of December. Since the comet is now moving away from the Earth and Sun this month, it should rapidly fade to magnitude ~11.4 by the end of the month. The comet is now an evening object as it moves from Auriga through Taurus into Eridanus.
I imaged the comet back on Oct. 21 with the University of Arizona’s Kuiper 1.5-m telescope. Though still over a month from perihelion and located low in the sky, the comet displayed an impressive tail and even some near-nucleus jet activity.
Finder charts can be found at Chasing Comets.
Ephemeris for C/2012 K5 (LINEAR) Date RA DEC Delta r Elong V 2012 Jan 01 06h 25m +45d 45' 0.294 1.259 157 8.5 2012 Jan 11 04h 40m +10d 17' 0.428 1.333 138 9.4 2012 Jan 21 04h 13m -04d 25' 0.673 1.418 116 10.6 2012 Jan 31 04h 04m -10d 35' 0.942 1.512 103 11.4 RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU r = distance from the Sun in AU, Elong = elongation from Sun in degrees V = Visual magnitude
On June 21, 1827, French astronomers Jean Louis Pons and Jean-Félix Adolphe Gambart discovered a comet among the stars of Cassiopeia. Both men were prolific comet finders. Pons was the most prolific discoverer of comets up until the modern era and still holds the record for most visual discoveries. A record that is unlikely to ever be broken. Between 1801 and 1827, Pons found 26 comets. Comet Pons-Gambart was his second to last comet find. Though not as prolific as Pons, Gambart is credited with 5 comet discoveries between 1822 and 1834. Comet Pons-Gambart was his 3rd find.
As the comet was already a few weeks past perihelion at discovery, it was only observed for ~1 month before it faded. Over the years, orbit computers have noticed that Pons-Gambart was on an obvious elliptical orbit and determined periods between ~45 and 65 years. The only problem was with periods that short the comet should have returned at least 2 to 4 times since 1827. Perhaps the comet was fainter now or even broke up in the intervening years to explain why it was constantly being missed.
Fast forward to this year… Robert Matson of Newport Coast, CA found evidence of an unknown comet on images taken with the SOHO spacecraft. SOHO’s SWAN imager is used to map the Lyman-α emission of the solar wind. SWAN is also very good at detecting hydrogen was dissociated water molecules released by comets. As a result, SWAN has been used to discover comets. Matson noted the presence of a comet on SWAN images from Nov. 7, 10, 11, 13 and 19. He then informed a number of observers about the new find and on Nov. 29 Terry Lovejoy of Australia found the comet.
Before the comet was even formally announed, Maik Meyer of Limburg, Germany noticed the similarities between the new SWAN/Matson comet and long-lost Comet Pons-Gambart. There is little doubt that the two are related and are probably the same object. Only problem is the 2012 observations don’t exactly match the 1827 observations assuming orbital periods of 45-65 years. A recent MPEC released by Gareth Williams of the Minor Planet Center found that the 2012 observations are consistent with a much longer period than previously assumed. It is likely that Pons-Gambart wasn’t really missed before because with a 188 year orbit this is actually its first return since 1827.
At first there was still come question as to whether the newly seen comet was Pons-Gambart and for awhile the comet was only known by its designation C/2012 V4. The Minor Planet Center has now officially announced it as 273P/Pons-Gambart.
The comet has been too close to the Sun to be seen since early December. By the end of the January, the comet will be far enough from the Sun to once again be seen by visual observers as it moved through the stars of Serpens Cauda. How bright it will be at the time is still uncertain though the comet could still be brighter than magnitude 9.
Finder charts can be found at Chasing Comets.
Ephemeris for 273P/Pons-Gambart Date RA DEC Delta r Elong V 2012 Jan 01 18h 51m -09d 54' 1.770 0.843 13 8.2 2012 Jan 11 18h 45m -05d 14' 1.773 0.911 19 8.4 2012 Jan 21 18h 38m -00d 30' 1.728 1.007 30 8.7 2012 Jan 31 18h 31m +04d 37' 1.646 1.120 41 9.0 RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU r = distance from the Sun in AU, Elong = elongation from Sun in degrees V = Visual magnitude