Comet C/2011 L4 (PANSTARRS) - Bright in 2013?

[Greg Bryant]

A new comet, C/2011 L4 (PANSTARRS), has been announced this morning. Discovered by the first telescope of the Pan-Starrs survey in Hawaii, the comet is currently predicted to reach perihelion in April 2013. It could become visible to the unaided eye.

More details to come...

Greg

[Liz]

What the!! Thank you Greg, you have made my day.

[luigi]

Great news! I hope this is friendly to the South Hemisphere observers, or I'll need to travel.
Yipppieeee!!!

[mozzie (Peter)]

thanks greg...i need a fix of a good comet it's been awhile.....

[mithrandir (Andrew)]

Originally Posted by Greg Bryant

A new comet, C/2011 L4 (Panstarrs), has been announced this morning. Discovered by the first telescope of the Pan-Starrs survey in Hawaii, the comet is currently predicted to reach perihelion in April 2013. It could become visible to the unaided eye.

More details to come...

Given the numbers in MPEC K11L33 and Horizons, perihelion 2013 Apr. 17 however JPL warns there is not enough data yet for an accurate orbit.

Based on current data for that date I get a magnitude estimate of 1.6 and it will be setting at around sunset. After April 17 it will be only above the horizon in daylight or too far north, until it returns mid August at mag 11 and fading.

For Sydney on the last few days of March and first of April it would be better, mag ~3 and setting around 21:15. RA ~1:40 and Dec -30, moving north a couple of degrees per day.

Let's hope more data will improve things.

[Greg Bryant]

Although the first orbit calculation on the MPEC this morning is based on ~2 weeks, thanks to a set of pre-discovery observations, it's certainly concentrated towards the last few days. The uncertainty in the date of perihelion is still perhaps a fortnight or so, not to mention the uncertainty in some other parameters - this happen with Elenin, where the data was jumping around a bit for a while.

With the magnitude parameters from Horizons, while they up the absolute magnitude by 2 (which is a nice estimate for visual vs the CCD data available), it assumes a brightening rate for a long-period comet rather than a first-time comet, and that's not known yet.

Hence my first post

Greg

[OneOfOne (Trevor)]

Can't they give it a hurry on? We are all supposed to be dead by 21st December the year before, missed by that much

I agree though, it is about time we had another naked eye comet. McNaught did so much to create an interest in astronomy, another boost would be great.

[Greg Bryant]

In all probability, there may be another as-yet-undiscovered naked-eye comet before then. On average, there is a comet of 6th magnitude or better every year or so, a comet of 4th magnitude or better every 2 years, a comet of 2nd magnitude or better every 5 years, and a comet of 1st magnitude or better every 10 years. That's the long-run average, which takes into account droughts and deluges.

Greg

[Suzy]

Originally Posted by Liz

What the!! Thank you Greg, you have made my day.

Liz, I yearn to see the day when you discover a comet and have it named after you. I wouldn't be surprised at all. And I'll get to tell everyone ever so proudly, "I know her!"
If anyone deserves a comet, this gal does.

[CometGuy]

The orbit published in MPEC K11L33 gives a perihelion of April 17, 2013, but since that Circular 2 additional prediscovery images were found on May 30, 2011. When you add astrometry from these images Perihelion is brought forward 2 months.

The result of that works in the northern hemisphere's favour (but at the expense of the Southern hemisphere - but that can be solved by travelling!). Lets hope the comet brightens well and we get a decent naked eye comet . Anyway the elements I calculate with all 36 available observations are as follows:

C/2011 L4

Perihelion 2013 Feb 12.38 TT; Constraint: e=1

q 0.32
Peri. 332.25
Node 67.08
e 1.0
Incl. 65.09

[Liz]

Originally Posted by Suzy

Liz, I yearn to see the day when you discover a comet and have it named after you. I wouldn't be surprised at all. And I'll get to tell everyone ever so proudly, "I know her!"
If anyone deserves a comet, this gal does.

thanks Suzy, alas, I will never deserve a comet as not patient enough!! About 10 years ago there was a comet around (? name) that our group was observing one night. It was literally zipping across the sky over our 6 hours observing night, and all the guys called it 'Comet Liz' ..... that is enough for me ... maybe.

[Outbackmanyep]

I won't hold my breath for this one, there are other fish to fry first!

Or comets to fry.........
And Liz, i reckon you should take the plunge one day and try doing some visual obs, we need more passionate female comet observers out there!

Cheers!

[Outbackmanyep]

The only comets of note so far to watch is:
C/2009 P1 Garradd
45P/ Honda-Mrkos-Pajdusakova

Comet C/2010 X1 Elenin may turn out not to be as bright as predicted but we'll see....... and P/2006 T1 Levy hasn't been recovered as yet from recent reports.

[CometGuy]

Latest orbit is out:

http://www.minorplanetcenter.net/mpec/K11/K11L51.html

February Perihelion and better placed for the northern hemisphere, although if it is really bright (eg mag 3 or brighter) we might get some views of the comet in the evening twilight early Feb, 2013.

Terry

[luigi]

Originally Posted by CometGuy

Latest orbit is out:

http://www.minorplanetcenter.net/mpec/K11/K11L51.html

February Perihelion and better placed for the northern hemisphere, although if it is really bright (eg mag 3 or brighter) we might get some views of the comet in the evening twilight early Feb, 2013.

Terry

Ty Terry, I'm crossing my fingers for this to be a great comet and offer some stunning views at twilight for us in the south hemisphere in 2013.

If this is really better for the N hemisphere I will have to visit my sister in the UK

[ngcles]

Hi All,

Has been a new set of orbital elements published for this comet that has caused yet another sigificant bounce in the perihelion date and the orbital inclination. Probably several more weeks to go before the orbit is nailed down, but this is how it stands at present:

M.P.E.C. 2011-M11 Issued 2011 June 17, 17:30


C/2011 L4 (PANSTARRS)
T 2013 Mar. 23.86124 TT MPC
q 0.3150603 (2000.0) P Q
Peri. 333.30917 +0.35872293 +0.22400832
Node 65.09482 +0.92945994 +0.00387820
e 1.0 Incl. 92.46497 -0.08615156 +0.97457952
From 54 observations 2011 May 21-June 11.


Best,

Les D

[luigi]

Thank you and sorry to ask but can you tell me what's the expected brightness based on the last data and how it will be seen from the South Hemisphere? Ty!

Originally Posted by ngcles

Hi All,

Has been a new set of orbital elements published for this comet that has caused yet another sigificant bounce in the perihelion date and the orbital inclination. Probably several more weeks to go before the orbit is nailed down, but this is how it stands at present:

M.P.E.C. 2011-M11 Issued 2011 June 17, 17:30


C/2011 L4 (PANSTARRS)
T 2013 Mar. 23.86124 TT MPC
q 0.3150603 (2000.0) P Q
Peri. 333.30917 +0.35872293 +0.22400832
Node 65.09482 +0.92945994 +0.00387820
e 1.0 Incl. 92.46497 -0.08615156 +0.97457952
From 54 observations 2011 May 21-June 11.


Best,

Les D

[mithrandir (Andrew)]

Originally Posted by luigi

Thank you and sorry to ask but can you tell me what's the expected brightness based on the last data and how it will be seen from the South Hemisphere? Ty!

MPEC doesn't supply a magnitude with the orbital elements.

JPL have M1= 6. M2= 10.5 in their "Comet physical & dynamic parameters" data, and these elements calculated using 55 observations for Jun 21 2011, and which differ a bit from MPEC.
$$SOE
2455733.500000000 = A.D. 2011-Jun-21 00:00:00.0000 (CT)
EC= 1.000465940853835E+00 QR= 3.027100489471750E-01 IN= 8.528173948630401E+01
OM= 6.558886142080000E+01 W = 3.335725096912954E+02 Tp= 2456362.424215855543
N = 5.951959991084002E-05 MA=-3.743331770195418E-02 TA= 2.027969705288987E+02
A =-6.496748384594785E+02 AD= 6.684586454211886E+91 PR= 1.157407291666667E+95
$$EOE

Feeding those numbers into CdC leads to an estimated mag 0.8 around March 22 2013 when it sets around sunset for most SH observers. The week or two before would be better located but less bright. eg on the 8th set is around 21:15.

[ngcles]

Hi Luis,

Originally Posted by luigi

Thank you and sorry to ask but can you tell me what's the expected brightness based on the last data and how it will be seen from the South Hemisphere? Ty!

Very hard to say with any certainty Luis remembering this comet is currently outside the orbit of Jupiter and we can't really say whether it will be a good performer or not in intrinsic brightness. Indeed the elements are still jumping around a lot because of the relatively small number of astrometric observations and shortness of the observed track. That''ll change in a month or so as the observed track gets longer.

Subject to correction here, but I don't think we even know whether this is a "first-timer" (notorious underperformers) or a "return-visitor". Given the elements above, There is a high likelyhood it will be a naked-eye object around perihelion, fairly probable that it will be reasonably bright but hard to say exactly how bright.

I'd be surprised if it didn't make 5th magnitude, fair chance of 1st or 2nd magnitude, maybe even a bit brighter if it is a particularly good performer. We'll know a lot more in several months time.


Best,

Les D

[luigi]

Andrew, Les, thank you!
We'll keep an eye on this comet, it seems promising!

A Beautiful bright comet at Sunset will be a great thing!