COMET LOVEJOY’S ACTIVE TAIL: Amateur astronomers around the northern hemisphere are reporting activity in the tail of naked-eye Comet Lovejoy (C/2013 R1). In Nagano, Japan, astrophotographer Kouji Ohnishi could see big changes in less than an hour of monitoring:
Michael Jäger saw the same “disconnection event” from his observatory in Masenberg, Austria, on Dec. 5th. The disturbance could be caused by a gust of solar wind or perhaps an episode of vigorous outgassing in the comet’s core.
Comet Lovejoy is now about as bright as a 4th magnitude star. It is visible to the unaided eye from the countryside and is an easy target for backyard telescopes even in urban areas. Monitoring is encouraged. Comet Lovejoy rises in the east just before the morning sun
COMET LOVEJOY FROM ORBIT: Veteran astronaut Dan Burbank has seen many amazing things. Once, he even flew through the aurora borealis. So when Burbank says “[Comet Lovejoy] is the most amazing thing I have ever seen in space,” it really means something. Currently serving onboard the International Space Station, Burbank photographed the sungrazing comet on Dec. 21st, an experience he describes in this NASA video:
Burbank describes the tail of Comet Lovejoy as a “green glowing arc at least 10 degrees long.” He saw it just before orbital sunrise emerging from Earth’s limb, which was “lit up as a bright sliver of blue and purple.”
After plunging through the sun’s atmosphere only 120,000 km above the stellar surface on Dec. 16th, and improbably surviving, Comet Lovejoy has become the finest comet since Comet McNaught in 2007. Its orbit is carrying it through the skies of the southern hemisphere where sunrise sky watchers are seeing the comet almost as clearly as Burbank did. One wonders if Burbank was looking out the window on Dec. 24th when Carlos Caccia took this picture of the ISS transiting Lovejoy’s tail over Intendente Alvear, Argentina:
“The ISS passed through the Southern Cross, continued parallel to the Milky Way, and finally arrived at the tail of Lovejoy with its typical golden color,” says Caccia. “What a lucky shot!”
The visibility of Comet Lovejoy should continue to improve in he mornings ahead as the comet moves away from the sun into the darker skies before dawn. Sky watchers should set their alarm for an early-Christmas treat
CONTINUED ADVENTURES OF COMET LOVEJOY: The scorched core of sungrazing Comet Lovejoy is still intact as it recedes from the sun. Even the comet’s flamboyant tail, temporarily lost in transit through the solar corona, has regrown. Click to view the last 24 hours of coronagraph images from the Solar and Heliospheric Observatory (SOHO):
SOHO images show two tails: the ion tail and the dust tail. The ion tail is made of gas and is blown directly away from the sun by the solar wind. The heavier dust tail is curved and more closely traces the comet’s orbit.
Now that the comet is more than five degrees from the sun, it is possible (albeit still not easy) for amateur astronomers to photograph it just before sunrise. A team led by Czech astronomer Jan Ebr captured this image at sunrise on Dec. 17th:
Credit: Jakub Cerny, Jan Ebr, Martin Jelinek, Petr Kubanek, Michael Prouza, Michal Ringes
“We used a remotely-controlled 12-inch telescope in Malargue, Argentina,” says Ebr. “The sun was below horizon at the time we took the picture, but just barely. There was only a 30 minute window between the rise of the comet and that of the sun “
COMET LOVEJOY SURVIVES: Incredibly, sungrazing Comet Lovejoy survived its close encounter with the sun yesterday. Lovejoy flew only 140,000 km over the stellar surface during the early hours of Dec. 16th. Experts expected the icy sundiver to be destroyed. Instead, NASA’s Solar Dynamics Observatory caught the comet emerging from perihelion (closest approach) apparently intact:
SDO also recorded Comet Lovejoy’s entry into the sun’s atmosphere: movie.
Comet Lovejoy began the week as a chunk of dusty, rocky ice more than 200 meters in diameter. No one can say how much of the comet’s core remains intact or how long it will hang together after the searing heat of perihelion. “There is still a possibility that Comet Lovejoy will start to fragment,” says researcher Karl Battams in a NASA news release. “It’s been through a tremendously traumatic event; structurally, it could be extremely weak.”
BIG COMET PLUNGES TOWARD THE SUN: Comet Lovejoy (C/2011 W3) is diving into the sun and furiously vaporizing as it approaches the stellar surface. The Solar and Heliospheric Observatory (SOHO) is recording the kamikaze plunge:
“This is, without any doubt, the brightest sungrazing comet that SOHO has ever seen,” says Karl Battams of the Naval Research Lab in Washington DC.
The comet’s nucleus, thought to be twice as wide as a football field, will skim approximately 140,000 km (1.2 solar radii) above the solar surface on Dec. 15/16. At such close range, solar heating will almost certainly destroy the comet’s icy core, creating a cloud of vapor and comet dust that will reflect lots of sunlight.
“If Comet Lovejoy gets as bright as magnitude -4 or -5, there is a tiny but non-zero chance that it could become visible in the sky next to the sun,” says Battams.
Indeed, something similar happened to Comet McNaught in January 2007 when it was visible in broad daylight: gallery. Standing in the shadow of a tall building to block the sun allowed the comet to be seen in blue sky nearby.
“Comet Lovejoy will be reaching perihelion (closest approach to the sun) right around sunset on Dec. 15th for people in the US East, Central, Mountain, and Pacific time zones,” continues Battams. “Be alert for the comet to the left of the sun at that time.” Caution: Do not look at or near the sun through unfiltered optics; focused sunlight can seriously damage your eyes.
Discovered on Dec. 2nd by amateur astronomer Terry Lovejoy of Australia, the comet is an unusually large member of the Kreutz family. Kreutz sungrazers are fragments of a single giant comet (probably the Great Comet of 1106) that broke apart back in the 12th century. SOHO sees one plunging into the sun every few days, but most are small, no more than 10 meters wide. Comet Lovejoy is at least ten times larger than usual.
COMET LOVEJOY HAS A COMPANION: “Comet Lovejoy has a friend!” notes Karl Battams in his blog. “Look for it in the upper-half of this animation moving perfectly in step with Lovejoy. It’s another Kreutz-group comet. This is not surprising. SOHO’s Kreutz-group comets are very ‘clumpy,’ for want of a better word. We frequently see them arrive in pairs or sometimes trios, and the big bright ones in particular will often have a little companion comet.”
