Comets PANSTARRS and Lemmon Still Linger for Early Morning Views

The comet show is still not over! Early on May 16, 2013, astrophotographer Chris Schur from central Arizona was able to see two comets at once, Comet PANSTARRS AND Comet Lemmon. “We set up on our 14 foot tall balcony observing pad and was able to get the very low Comet Lemmon as it rose in the eastern sky,” Chris told Universe Today via email. “While PANSTARRS was up high by 2:30am, we had to wait until 3:30 before we could try Lemmon.”

While neither comet was visible to the naked eye, Chris reported that both were seen quite clearly in the 11×80 binoculars. “It was fun to go back and forth rapidly between the two objects to compare,” he said. “While PANSTARRS is now a very low surface brightness wedge shaped object, Lemmon was just a huge ball of light, about two magnitudes brighter.”

Comet Lemmon as seen over central Arizona on May 16, 2013. Credit and copyright: Chris Schur.
Comet Lemmon as seen over central Arizona on May 16, 2013. Credit and copyright: Chris Schur.

If you look carefully you can see the comets are stationary, and the stars are slightly trailed from the motion against the starry background.

“One point Id like to make is that PANSTARRS is currently exhibiting one of the most spectacular anti tails I have ever seen,” Chris said. “I have imaged hundreds of comets but never one with such a long sunward spike. This comet is VERY special.”

When viewed edge on from Earth, the anti tail appears as a spike projecting from the comet’s coma towards the Sun It is geometrically opposite to the other tails: the ion tail and the dust tail.

Thanks to Chris for sharing his great images of these comets!

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Comet Lemmon, Now in STEREO

An icy interloper was in the sights of a NASA spacecraft this past weekend.

Comet 2012 F6 Lemmon passed through the field of view of NASA’s HI2A camera as seen from its solar observing STEREO Ahead spacecraft. As seen in the animation above put together by Robert Kaufman, Comet Lemmon is now displaying a fine ion and dust tail as it sweeps back out of the inner solar system on its 10,750 year plus orbit.

Comet Lemmon has been a dependable performer for southern hemisphere observers early in 2013. As we reported earlier this month for Universe Today, this comet is now becoming a binocular object low in the dawn sky for northern hemisphere astronomers.

Comet Lemmon passed perihelion at 0.73 astronomical units from the Sun on March 24th. It’s currently in the +4th to +5 magnitude range as it heads northward through the constellation Pisces.

NASA’s twin Solar TErrestrial RElations Observatory (STEREO) spacecraft often catch sungrazing comets as they observe the Sun. Known as STEREO A (Ahead) & STEREO B (Behind), these observatories are positioned in Earth leading and trailing orbits. This provides researchers with full 360 degree coverage of the Sun. Launched in 2006, STEREO also gives us a unique perspective to spy incoming sungrazing comets. Recently, STEREO also caught Comet 2011 L4 PanSTARRS and the Earth as the pair slid into view.

Another solar observing spacecraft, the European Space Agencies’ SOlar Heliospheric Observatory (SOHO) has been a prolific comet discoverer. Amateur comet sleuths often catch new Kreutz group sungrazers in the act. Thus far, SOHO has discovered over 2400 comets since its launch in 1995. SOHO won’t see PanSTARRS or Lemmon in its LASCO C3 camera but will catch a glimpse of Comet 2012 S1 ISON as it nears the Sun late this coming November.

Like SOHO and NASA’s Solar Dynamics Observatory, data from the twin STEREO spacecraft is available for daily perusal on their website. We first saw this past weekend’s animation of Comet Lemmon passing through STEREO’s field of view on the Yahoo STEREOHunters message board.

Here’s a cool but largely unrecognized fact about comets. As they move back out of the solar system, their dust tail streams out ahead of them, driven by the solar wind. I’ve even seen a few science fiction flicks get this wrong. We simply expect comets to always stream their tails out behind them!

Another observatory in our solar observing arsenal has also moved a little closer to operability recently. The Interface Region Imaging Spectrograph (IRIS) arrived at Vandenberg recently in preparation for launch this summer on June 26th. IRIS will be deployed from a Pegasus XL rocket carried aloft by an L-1011. NuSTAR was launched in a similar fashion in 2012. A Pegasus XL rocket will also launch the TESS exoplanet hunting satellite in 2017.

Keep an eye out for Comet Lemmon as it emerges from the dawn twilight in the days ahead. Also, be sure to post those pics to Universe Today’s Flickr community, and keep tabs on the sungrazing action provided to us by SOHO and STEREO!

 

Comet Lemmon: A Preview Guide for April

As Comet 2011 L4 PanSTARRS moves out of the inner solar system, we’ve got another comet coming into view this month for northern hemisphere observers. 

Comet C/2012 F6 Lemmon is set to become a binocular object low to the southeast at dawn for low northern latitudes in the first week of April. And no, this isn’t an April Fools’ Day hoax, despite the comet’s name. Comet Lemmon (with two m’s) was discovered by the Mount Lemmon Sky Survey (MLSS) based outside of Tucson, Arizona on March 23, 2012. MLSS is part of the Catalina Sky Survey which searches for Near Earth Asteroids. We’ve got another comet coming into view this month for northern hemisphere observers as Comet 2011 L4 PanSTARRS moves out of the inner solar system.

The comet is on an extremely long elliptical orbit, with a period of over 11,000 years. Comet Lemmon just passed perihelion at 0.74 astronomical units from the Sun on March 24th.

Animation of Comet Lemmon as it passes the star Gamma Crucis on January 17th. (Courtesy of Luis Argerich. Used with permission).
Animation of Comet Lemmon as it passes the star Gamma Crucis on January 17th. (Courtesy of Luis Argerich. Used with permission).

Southern hemisphere observers have been getting some great views of Comet Lemmon since the beginning of this year. It passed only three degrees from the south celestial pole on February 5th, and since that time has been racing up the “0 Hour” line in right ascension. If that location sounds familiar, that’s because another notable comet, 2011 L4 PanSTARRS has been doing the same. In fact, astrophotographers in the southern hemisphere were able to catch both comets in the same field of view last month.

Another celestial body occupies 0 Hour neighborhood this time of year. The Sun just passed the vernal equinox marking the start of Spring in the northern hemisphere and Fall in the southern on March 19th.

And like PanSTARRS, Comet Lemmon has a very steep orbit inclined 82.6° relative to the ecliptic.

The steep path and current position of Comet Lemmon. (Credit: NASA/JPL' Small-Body Database Browser).
The steep path and current position of Comet Lemmon. (Credit: NASA/JPL’ Small-Body Database Browser).

Comet Lemmon broke naked-eye visibility reaching +6th magnitude in late February and has thus far closely matched expectations. Current reports place it at magnitude +4 to +5 as it crosses northward through the constellation Cetus. Predictions place the maximum post-perihelion brightness between magnitudes +3 and +5 in early April, and thus far, Comet Lemmon seems to be performing right down the middle of this range.

Brightness graph for Comet Lemmon for the months surrounding perihelion. (Created by author).
Brightness graph for Comet Lemmon for the months surrounding perihelion. (Created by author).

Southern observers have caught a diffuse greenish 30” in diameter nucleus on time exposures accompanied by a short, spikey tail. Keep in mind, the quoted brightness of a comet is extended over its entire surface area. Thus, while a +4th magnitude star may be easily visible in the dawn, a 3rd or even 2nd magnitude comet may be invisible to the unaided eye. Anyone who attempted to spot Comet PanSTARRS in the dusk last month knows how notoriously fickle it actually was. Binoculars are your friend in this endeavor. Begin slowly sweeping the southeast horizon about an hour before local sunrise looking for a fuzzy “star” that refuses to reach focus. Comet Lemmon will get progressively easier in the dawn sky for latitudes successively farther north as the month of April progresses.

The apparent path of Comet Lemmon for April looking southeast about an hour before local sunrise from latitude 30 degrees north. (Created by the Author using Starry Night).
The apparent path of Comet Lemmon for April 10th through the 30th looking east about an hour before local sunrise from latitude 30 degrees north. (Created by the Author using Starry Night).

Comet Lemmon will continue to gain elevation as it crosses from Cetus into the constellation Pisces on April 13th. An interesting grouping occurs as the planet Mercury passes only a few degrees from the comet from April 15th to April 17th. Having just past greatest elongation on March 31st, Mercury will shine at magnitude -0.1 and make a good guide to locate the comet in brightening dawn skies. The pair is joined by the waning crescent Moon on the mornings of April 7th and 8th which may also provide for the first sighting opportunities from low north latitudes around these dates.

The apparent path of Comet Lemmon for April looking southeast about an hour before local sunrise from latitude 30 degrees north. (Created by the Author using Starry Night).
Mercury meets Comet Lemmon on April 15th as seen about an hour before local sunrise from latitude 30 degrees north. (Created by the Author using Starry Night).

The Moon reaches New phase on Wednesday, April 10th at 5:35AM EDT/9:35 UT. It will be out of the morning sky for the next couple of weeks until it reaches Full on April 25th, at which point it will undergo the first eclipse of 2013, a very shallow partial. (More on that later this month!)

Comet Lemmon will then slide across the celestial equator on April 20th and cross the plane of the ecliptic on April 22nd as it heads up into the constellation Andromeda in mid-May. We’re expecting Comet Lemmon to be a fine binocular object for late April, but perhaps not as widely observed due to its morning position as PanSTARRS was in the dusk.

By mid-May, Comet Lemmon will have dipped back down below +6th magnitude and faded out of interest to all but a few deep sky enthusiasts. Comet Lemmon will pass within 10° of the north celestial pole on August 9th, headed back out into the icy depths of the solar system not to return for another 11,000-odd years.

It’s interesting to see how these two springtime comets will effect observers expectations for the passage of Comet C/2012 S1 ISON. Will this in fact be the touted “Comet of the Century?” Much hinges on whether ISON survives its November 28th perihelion only 1,166,000 kilometers from the center of our Sun (that’s 0.68 solar-radii or about 3 times the Earth-Moon distance from the surface of the Sun). If so, we could be in for a fine “Christmas Comet” rivaling the passage of Comet Lovejoy in late 2011. On the other hand, a disintegration of Comet ISON would be more akin to the fizzle of Comet Elenin earlier in 2011.

In the meantime, enjoy Comet Lemmon as an Act 2 in the 2013 Three Act “Year of the Comet!

Astrophoto: A Night of Two Comets

While those of us in the northern hemisphere are impatiently waiting to see Comet PANSTARRS (tonight, March 7 it should be visible in the southern parts of the US and Europe just after twilight), southern hemisphere observers have been dazzled by not one but TWO comets. Here, astrophotographer Guillermo Abramson captures both PANSTARRS and Comet Lemmon in one shot on March 4, 2013!

Below is a great shot Abramson took of Comet PANSTARRS on March 3:

Comet PANSTARRS sets behind Mt. Cathedral, in Bariloche, Argentina. Credit and copyright: Guillermo Abramson.
Comet PANSTARRS sets behind Mt. Cathedral, in Bariloche, Argentina. Credit and copyright: Guillermo Abramson.

If you need info on how to see Comet PANSTARRS this month, check out our detailed guide here.

With this being the Year of the Comets make sure to submit all your comet astrophotos to our Flickr page. We’ll be posting more images from comet-watchers soon!

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.