Amateur astronomer discovers sungrazing comet

By Phil Plait | December 4, 2011 11:13 am

Back in the day, it used to be that most new comets and asteroids were discovered by astronomers diligently sitting at their eyepieces, spending one cold night after another patiently scanning the skies. The advent of robotic astronomy changed that, and now the vast majority of all celestial newcomers are found automatically.

But Australian "amateur" astronomer Terry Lovejoy changed that last week: not only did he discover a comet — which isn’t that unusual, though still cool — but it turns out to be a sungrazer, a comet that plunges deep down to the center of the solar system, practically skimming the Sun’s surface.

Here is Lovejoy’s discovery image:

This is a combination of three images; the comet moves between exposures a bit so he re-centered the comet in each shot and added them together. It’s the fuzzy blob in the middle of the frame. The comet’s official name is C/2011 W3 (Lovejoy), and on December 16th it will pass just about 880,000 km (500,000 miles) from the Sun’s surface — only a little bit more than than the radius of the Sun itself! 180,000 km (110,000 miles) — less than half the distance from the Earth to the Moon!* This may be a death dive, since many such comets don’t survive the intense heat of the Sun from that distance. Comets are composed of lots of rock held together by ice, so when the ice vaporizes, the comets disintegrates.

Michael Mattiazzo took the shot shown here of the comet on the evening of December 2. It’s a combination of ten short exposures lasting only minutes in total, but the comet moves enough during that time to trail in the final image. As you can see, it’s faint but moving rapidly as it heads down to its rendezvous with the Sun. You can also see more images of it at Astro Bob’s website.

Sometimes these sungrazer comets — technically called Kreutz family comets, after the man who figured out they all came from the same parent comet — survive their passage and sometimes they don’t. Sometimes they also get bright enough to be seen with the naked eye, though 2011 W3 is pretty faint right now and probably won’t brighten. But comets are difficult to predict; each is different and can surprise us. If this one flares up I’ll be sure to let you know.

This is a pretty good find by Mr. Lovejoy: most sungrazer comets are first seen when they appear in data from the SOHO solar observing satellite, already very near the Sun. It’s hard to find them when they’re far from the Sun since they’re usually so faint, and in fact this is the first such sungrazing comet found from the ground in over 40 years! So it’s quite a nice discovery. Congrats to Mr. Lovejoy, and we’ll have to see what happens to his comet over the next couple of weeks!

Image credits: Terry Lovejoy, courtesy José Luis Galache; Michael Mattiazzo. Both used by permission.


* I originally found a set of numbers that gave the closest approach distance to the Sun of 880,000 km, but turns out that was the distance to the Sun’s center. Subtracting the Sun’s radius of 695,000 km yields the surface-skimming distance of roughly 180,000 km. My apologies for the error.


Related posts:

The comet and the Coronal Mass Ejection
NASA’S SDO captures final moments of a comet streaking across the Sun
Amazing video of comet on a solar death dive
Ten Things You Don’t Know About Comets

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (21)

  1. Kathy King

    Very cool, but I think Mr. Lovejoy’s name is cooler!

  2. That’s 880,000 km from the Sun’s *center* and only 140,000 km from the surface – perihelion distances always refer to the center of mass.

  3. Do sungrazing comets have tails that are unusually thick and luminous? I wonder, when comets get very close to the sun, does their offgassing increase roughly with the inverse square law?

  4. Cool fact #1: Around 85% of sungrazing comets belong to the Kreutz group, and there are probably several thousand of them still whizzing on their way to the Sun.

    Cool fact #2: SOHO has discovered over 1,500 Kreutz comets since it was launched in 1995.

    —JL Galache
    Minor Planet Center

  5. Downer

    Major bummer, you finally get a celestial object named after yourself and then Death from the sun!

  6. @$ JL Galache: Aren’t Kreutz comets supposed to be fragments of a single comet that broke up? Thousands? Just how big was that original comet, I wonder!?

  7. Messier Tidy Upper

    Australian “amateur” astronomer Terry Lovejoy ..

    Would that be *Reverend* Lovejoy by any chance? ;-)

    Joking aside that is one awesome finding for an ‘amateur’ astronomer – superb news! (& by a fellow Aussie too!) :-)

    @4. JL Galache : cool & very impressive facts indeed. Thanks – & well done SOHO team an oft overlooked but wonderful mission. :-)

    If memory serves, I think the Parkes Dish has discovered well over a thousand pulsars .. & Corot / Kepler (one of those?) has detected around that many exoplanet candidates hasn’t it?

  8. Silly question, but I wonder if there are fewer observatories in the southern hemisphere (less population and whatnot)? If so, does this mean that your odds of discovering something that the big observatories missed are greater down under?
    ‘Cuz if so, I’m making a mental note to take some Australian language lessons and buy a drop-bear helmet ;)

  9. Also, I hope there aren’t that many sun-grazing comets. I mean, if we lose too much sun to overgrazing… er…
    Ok, I’m tired as hell, someone else is going to have to finish the pun for me :-P

  10. Jeanette

    :) Congratulations on comet number 3 Terry. It’s well deserved too, your dedication to the hobby is amazing. You are an inspiration to all Amateur Astronomers.

  11. @6 Joseph G:

    We’ve been observing Kreutz group comets since at least 1843, and studies by Brian Marsden point to the Great Comet of 371 B.C. as the parent body of this group. SOHO is discovering some 100 Kreutz comets per year, so even if we assume these past 15 years have been particularly prolific, it’s still easy to come up with “thousands” for the number of fragments out there. If these past years have been typical, then we’re talking tens or hundreds of thousands of fragments.

    If the progenitor comet was several dozen kilometers in diameter, let’s say 60 km (the approximate size of Comet Hale-Bopp), it would have weighed some 55 x 10^15 kg. That’s about 7,000 Temple 1 comets! And the Kreutz comets SOHO is seeing are much, much smaller than Temple 1.

    —JL Galache
    Minor Planet Center

  12. Graham W. Wolf

    Nice comet, but rather faint in my 18cm Newtonian at 200x. It’s strong angular motion reminds me of the near-perihelion passages of 2 favourites (1965f Ikeya-Seki, and 1996B2 Hyakutake)… the former being perhaps the most famous sungrazer of them all.

    Latest of 3 observations makes C/2011W3 (Lovejoy) at Mv 11.0, 0.8 arcmin coma, DC3 at December 05.618 UT. My first observation of the comet, on December 01.608 UT (having estrapolated the discovery positions by Terry Lovejoy for Nov 27th and 29th), placed the comet near Sigma Lupi, and some 12 linear deg or so from Alpha Centauri. It was found after 6 minutes of careful searching at Mv 11.8 at 200x, with a 0.6 arcmin coma and Dc of 3. It was also visually observed on December 02.588 UT.

    All observations were done from the Barber Grove Observatory (BGO) at Lower Hutt, near where the Hutt river flows into the Wellington Harbour (NZ). This morning’s observation (NZDT) was done in increasing semi-overcast skies , that have since developed into quite heavy rain in the last hour or so! The comet’s angular motion at 200x is quite noticeable after only about 5 minutes observation, against the fainter background stars.

    Here in Southern latitudes, ( BGO = -41.22875, +174.90300, 3.0m amsl) it appears best to look for the comet only about an hour or so before dawn onset. With narowing Solar Elongation, that will be even trickier to achieve later this week!

    Also, don’t forget the total Lunar Eclipse next week!

    Regards

    Graham W. Wolf
    (Lower Hutt, NZ)

  13. @#11 JL Galache: Wow! I had no idea there was so much variation in size between comets.

  14. psuedonymous

    Sungrazers have always worried me. Not only does the rapid outgassing caused by that close a pass mean they could change trajectory rapidly and unpredictably while hidden from view, they can also gain significant velocity from passing that close (gravitational slingshot), as well as break up into a closely associated shotgun-blast of rubble, which will already be soot-black (not from the close passage around the sun, but from collected dust) and difficult to observe against the glare of the sun as they swing round and pepper the Earth’s surface.
    At least we can see regular comets coming from a while away.

  15. Graham W. Wolf

    Greetings to everyone out there…

    Only one more personal observation of C/2011W3 (Lovejoy) since my last post. Weather here in Lower Hutt, NZ, expected to improve for this weekend. Comet earlier this week in my 18cm f5 Newtonian at 200X, had “risen” to Mv 10.5, and is headed this weekend for the Norma border with Scorpius… passing a few degrees from Antares as it approaches perihelion at Dec 16.00.

    For December 9th, a preliminary ephemeris places the comet at:-
    RA 16:25:36 DEC -42:34:12 M1= 9.8 Solar Elongation 21.1 deg

    You may be able to pick up the comet about half an hour or so, before dawn onset. I’ll be trying on the morning of the 11th, as the total lunar eclipse ends just before dawn, the Full Moon sets in the West…. and I get about 20mins of dark sky to “play with”. Will have my 10x50s and 11x90s handy, as scope “back-ups”.

    Given Comet Lovejoy’s predicted perihelion distance of ~ 120,000km, there’s no conceivable way I reckon it’ll survive Dec 16.0UT.

    Good luck with the observing and heartiest congratulations to Terry in Australia for his 3rd comet discovery (I’ve already seen the other two)!

    Best wishes and clear skies from me.

    Graham Wolf:- Lower Hutt, New Zealand. Barber Grove Observatory (BGO).
    12:08 NZDT

  16. Graham W. Wolf

    Hi to all!

    Latest visual observations from the Barber Grove Observatory (BGO) at Lower Hutt, NZ, for those interested:-

    Dec 06.615 UT Mv 9.6 0.8 arcmin coma DC 3
    Dec 09.618 UT Mv 8.5 0.8 arcmin coma DC 4

    An 18cm f5 Newtonian at 200x was used for both observations.

    The FRAM team:- SCT and CCD have just posted the latest data from Argentina for Comet Lovejoy C/20011 W3, which I have tabulated below:-

    Dec 06.32 UT Mv 10.9 coma 0.8 arcmin
    07.33 9.7 0.7
    08.33 8.8 1.4
    10.34 7.2 1.3
    11.35 6.1 1.0

    Please be careful with further semi-perihelion observations, given the rediculously small solar elongations for the comet that prevail at present. Serious eye injury (or worse!) awaits the careless. I understand that some remote SOHO images may become available later this week, as the comet moves closer into the solar FOV.

    Best wishes
    Graham Wolf
    (Barber Grove Observatory), Lower Hutt, New Zealand

    On Dec 09 UT, the near Full Moon (low in the West) set behind some thick cloud, barely 20min before dawn onset! The following night:- the sky was covered in thick haze, and no observation of the Total Lunar Eclipse was possible. Thick haze (and possible rain forecast for the next 2 days) has stopped visual observations here for now.

  17. Graham W. Wolf

    Greetings to all from NZ.

    No further observations from the Barber Grove Observatory in Lower Hutt, since my last recent post. We’ve had torrential rains this week, with serious flooding in Central New Zealand, and even more predicted for the next 3 to 5 days. The latest ground based sighting I am aware of, for Comet Lovejoy C/2011W3 is as follows from Amorim:- based in Brazil.

    Dece 15.52UT Mv -4.0 10×50 Binoc.

    This makes the comet just 0.5UT from Perihelion, being slightly fainter than Venus at opposition.

    Best Wishes

    Graham Wolf

  18. Graham Wolf

    Greetings to all from NZ!

    Well:- the comet DID survive perihelion, amd sprouted a faint ion tail in the process… the LASCO images posted just a few hours ago by NASA are truely stunning!!
    !
    The comet’s discoverer:- Terry Lovejoy managed a marginal set of brief images in his C8 on December 17.049 UT making the comet ~ Mv -1.2, with a coma of ~ 0.5 arcminute. Alex Amorim managed to sight the comet (just) in daylight on December 18.34 UT from Brazil. He reckoned the comet was a little fainter than Mv -1.0. Terry Lovejoy responded again on December 18.852 UT, with an observation of Mv -0.8, a coma of ~ 0.5′ and DC of 8.

    Yoshida of Japan provides the updated ephemeris for Lovejoy C/2011W3 which I have tabulated below.

    The comet is located in Ophiuchus, and about halfway between M7 (“stinger of the Scorpion” and planet Mercury. I just “MAY” have made a faint observation this morning in increasing twilight with my 10 x 90 Binocs and 11cm f5 Newtonian, but need to try again tomorrow morning, to actually confirm this!

    DECEMBER 17 RA 17:17.39 DEC -25:10.1 ELONG 4 deg Mv 0.5
    24 16:59.06 -41:00.1 21 9.2

    Best wishes and clear skies!

    Graham W. Wolf:-
    Barber Grove Observatory (BGO) -41.22875 +174.90300 3.0m amsl
    (Lower Hutt, New Zealand).

  19. Graham Wolf

    Yestereday’s post-perihelion sightings of Comet Lovejoy C/2011W3 are confirmed.

    Following data for those interested…

    DEC 18.674 UT Mv -0.5 coma 0.5′ DC6 18cm f5 Newtonian 100x
    18.677 UT Mv -0.8 coma ~1′ DC8 10×90 Binocular
    19.674 UT Mv-0.0 coma ~1′ DC6 10×50 Binocular

    Comet is currently just a few degrees from Epsilon Scorpii (Mv 2.28).

    Barber Grove Observatory (BGO) -41.22875 +174.90300 3.0m amsl

    Regards:- Graham W. Wolf (WOL01).

  20. Matt Shirley

    Thanks for the information Graham Wolf.
    I enjoyed viewing comet lovejoy on boxing day and the partial lunar eclipse with you on the 4th.
    Weather was shocking for the Venus transit here but at least you go to project an image of it during a break in the clouds from down your way.

    Currently processing Lunar data.
    Great to here some people liked the eclipse image from the 4th of June.

    I wasn’t aware you had equipment to view at 200x.
    I’d love to come down to your facilities and capture some images.

    would be great to get some high detail planetary shots for processing.
    I’ll catch up with you again soon.

    Once my Optical capturing upgrade arrives we should
    be able to get some great raw images.

    Take care Graham.

    From Matt Shirley

    AVIPS Upper Hutt
    Astronomical Viewing and Image Processing.

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