Naked eye comet suddenly comes into view

[Weather-history]

This is going around the wires, out of nowhere a 14th magnitude periodical comet called Holmes that is currently on view has dramatically brightened to magnitude 3 and is now naked eye in Perseus.

http://www.space.com/spacewatch/071025-comet-holmes.html

Edited October 24, 2007 by Mr_Data

[Bobby]

I wonder what has caused it to be become so bright. Perhaps one side is particularly reflective and at a certain position reflects right onto us? Who knows, interesting though.

[Chris Knight]

I wonder what has caused it to be become so bright. Perhaps one side is particularly reflective and at a certain position reflects right onto us? Who knows, interesting though.

Probably a blast of solar wind from the recent coronal mass ejections on the sun, which are getting more frequent at the end of the solar minimum.

See the solar and aurora activity chat on this forum, and http://spaceweather.com

[Bottesford]

Would love to see that! Pity its coincided with never ending cloudy skies...

[parmenides3]

As ever, Mr Data, you are one step ahead of the rest of us. Thanks for posting this. I have my telescope out and ready to go, waiting for clear skies. Are we not due some meteor showers around now, too?

:)P

[Cat 5]

Thanks Mr Data - great work.

Should this be visible now or will we have to wait until this evening? If anyone can see it, please report in!

[Weather-history]

The good news is when the comet last flared up in 1892, it remained fairly bright for quite a while. Hard to tell what it might do next but we have a chance to see it over the next few nights.

http://www.skyandtelescope.com/observing/h...s/10775326.html

Edited October 25, 2007 by Mr_Data

[BLAST FROM THE PAST]

Probably a blast of solar wind from the recent coronal mass ejections on the sun, which are getting more frequent at the end of the solar minimum.

See the solar and aurora activity chat on this forum, and http://spaceweather.com

The sun is still very very quiet isn't it.

BFTP

[shuggee]

Looking NE:

[Chris Knight]

The sun is still very very quiet isn't it.

BFTP

In terms of sunspots, yes, but the current episodes of CMEs are massive and causing aurorae with unexpected frequency, for a supposedly quiet sun. We have a short history of solar observation from heliospheric satellite observatories, and are learning a huge amount about what goes on in our star. The quiet sun is a misnomer - it is always active, apparently, albeit with different phenomena. In four or five years time we will be prepared to witness the magnetic reversal process in much more detail than ever before, and no doubt will be in for some surprises!

Welcoming the first new sunspot cycle of the 21st Century, and lots more comets!

[James M]

As ever, Mr Data, you are one step ahead of the rest of us. Thanks for posting this. I have my telescope out and ready to go, waiting for clear skies. Are we not due some meteor showers around now, too?

:)P

The Orionids peaked on the 21st but they can still be seen till the 7th November and the next main one is the Leonids which peaks in the early hours of November 18th.

Edited October 25, 2007 by James M

[Andy Bown]

For the last 6 or so weeks my girlfriend and I have regularly looked out for a star to the NE and now E (best viewing around 7-10pm) that keeps changing colour, especially between hues of green and red. A Google search says that it is scintillatting, however is there a chance that what we have been seeing is this comet?

I wish it were clear this evening :lol: .

Edited October 25, 2007 by Andy Bown

[Osbourne One-Nil]

Time to polish off my twelve inches and get it pointing upwards.

[Crepuscular Ray]

For the last 6 or so weeks my girlfriend and I have regularly looked out for a star to the NE and now E (best viewing around 7-10pm) that keeps changing colour, especially between hues of green and red. A Google search says that it is scintillatting, however is there a chance that what we have been seeing is this comet?

I wish it were clear this evening :lol: .

Unlikely, Andy, as this comet has only brightened to within naked-eye range within the last couple of days and would have been difficult in even large amateur 'scopes before that. At magnitude +2.5 it is not currently visible during daylight hours.

I wouldn't normally suggest looking at Wikipedia because it can be unreliable at times, but the explanation of what - perhaps - causes outgassing might explain why this comet has brightened suddenly.

[shuggee]

Time to polish off my twelve inches and get it pointing upwards.

A quick spit on the lense, and a good buff should get it working fine.

Shame the Atlantic is wakening up across the northern UK to spoil the crystal clear nights we've become accustomed to.

[snowsure]

Assuming that the comet is 2.5AU from the sun, how long would it have taken a CME to arrive there?

I also wonder if the brightening event in 1892 was accompanied by a similar amount of solar activity.

Seems more plausible than a meteroid/asteroid strike to me.

[Chris Knight]

Assuming that the comet is 2.5AU from the sun, how long would it have taken a CME to arrive there?

I also wonder if the brightening event in 1892 was accompanied by a similar amount of solar activity.

Seems more plausible than a meteroid/asteroid strike to me.

Problems:

All our satellite data is focussed on solar events directed generally towards earth, not necessarily towards the point in space where the comet is, somewhere in Perseus from our viewpoint, and off the ecliptic plane.

A rough and ready method, making lots of assumptions:

To cause a brightening in the comet, we should assume a fast burst of Solar wind, carrying lots of hot protons and electrons.

The first thing to find is the velocity of the solar wind, currently high at 628.9 km/sec according to http://spaceweather.com , so assuming a max of roughly 700km/sec, the current solar wind has taken about 59 hours or 2.5 days to get here from the sun, or 6-6.5 days from the sun to the comet.

SOHO is about 150,703,456 kilometers (92 million miles) from the Sun and only about 1,528,483 Kilometers (1 million miles) from the Earth (three times farther than the moon). This orbit is around a mathematical point between the Earth and the Sun known as the Lagrange point or the L1 point.

1 AU = 149,597,870.691 kilometers therefore 2.5 AU is approximately 375,000,000 km

So the emergent CME seen by the SOHO/LASCO instrument hits the vicinity of earth's orbit about 2.5 days later, and 4 days later, the comet assuming it is 2.5 AU from the sun.

Spaceweather. com has aurorae photos on Oct 2,3,4,8,18,19,25,26

The comet brightened on 23 Oct, so we are looking for a CME around the 15th October, with possible aurorae on the 18th-19th, which we have!

With the current preliminary SOHO/LASCO CME list, to be able to pinpoint a possible CME event detected at the observatory

Excerpt from:

ftp://lasco6.nascom.nasa.gov/pub/lasco/st...O_CME_List_2007

11-Oct-2007:

************

05:54 ENE - Very thin loop (jet-like) front. It fades through C2.

08:54 E - Very thin (jet-like) loop front toward ESE. It fades through C2.

09:30 E - Bright elongated (slightly asymmetric) loop front toward ESE

(southern part brighter). WIDTH in C3 at 12:18 UT: < 15 deg.

12:54 WNW - Couple of fronts, very faint and diffuse, that fade through C2.

18:54 NNW - Very faint and diffuse spray-like front that quickly fades.

**** LASCO Data Gap between 21:53 - 00:55 UT (next day) ****

**** -C2 time- due to EIT Shutterless Run #1. ****

----------------------------------------------------------------------------------

12-Oct-2007:

************

10:54 SSE - Jet-like front.

11:30 ENE - Very narrow and elongated loop (jet-like) front.

16:54 NE - Extremely faint (barely discernible) loop front.

----------------------------------------------------------------------------------

13-Oct-2007:

************

**** No significant activity.

----------------------------------------------------------------------------------

14-Oct-2007:

************

00:54 NNW - Jet-like front.

15:06 SE - Extremely faint front starts to be discernible.

----------------------------------------------------------------------------------

15-Oct-2007:

************

09:54 E - Diffuse front toward ESE.

23:54 ENE - 'Pair formation' well above the C2 occulting disk.

----------------------------------------------------------------------------------

16-Oct-2007:

************

07:31 SE - Very diffuse and elongated loop-like front. It fades through C2.

16:30 NE - Slow development of a sytem of faint (slightly expanding) loop

fronts. Core (apparently twisted) material starts to be seen

by ~ 20:06 UT.

----------------------------------------------------------------------------------

17-Oct-2007:

************

08:30 WNW - Elongated ragged front (apparently twisted trailing material).

Gusty outflow. It fades throughout C3.

13:06 NNE - Diffuse and very narrow loop front. It fades throughout C2.

**** LASCO Data Gap between 21:51 - 01:05 UT (next day) ****

**** -C2 time- due to EIT Shutterless Run #2. ****

----------------------------------------------------------------------------------

18-Oct-2007:

There are plenty of events, although nothing stands out :lol:

However the solar wind velocity varies, perhaps we need some recent data:

http://www.swpc.noaa.gov/ace/MAG_SWEPAM_7d.html

damn, too short a timescale, need to see the archived data

http://www.swpc.noaa.gov/ftpdir/lists/ace2...e_swepam_1h.txt

Excerpt 18-20th Oct:

# Hourly Averaged Real-time Bulk Parameters of the Solar Wind Plasma

#

# Modified Seconds ------------- Solar Wind -----------

# UT Date Time Julian of the Proton Bulk Ion

# YR MO DA HHMM Day Day S Density Speed Temperature

#-------------------------------------------------------------------------

2007 10 18 0000 54391 0 0 1.7 329.5 3.90e+04

2007 10 18 0100 54391 3600 0 2.0 349.4 6.90e+04

2007 10 18 0200 54391 7200 0 2.0 357.8 7.21e+04

2007 10 18 0300 54391 10800 0 1.3 357.8 6.88e+04

2007 10 18 0400 54391 14400 0 1.4 354.8 9.32e+04

2007 10 18 0500 54391 18000 0 2.1 373.5 5.78e+04

2007 10 18 0600 54391 21600 0 1.8 377.8 5.27e+04

2007 10 18 0700 54391 25200 0 2.9 393.3 8.40e+04

2007 10 18 0800 54391 28800 0 4.8 416.6 8.30e+04

2007 10 18 0900 54391 32400 0 4.8 420.4 8.33e+04

2007 10 18 1000 54391 36000 0 4.4 424.4 1.02e+05

2007 10 18 1100 54391 39600 0 3.9 417.5 1.07e+05

2007 10 18 1200 54391 43200 0 2.9 410.8 9.87e+04

2007 10 18 1300 54391 46800 0 2.8 414.4 8.07e+04

2007 10 18 1400 54391 50400 0 3.8 438.8 1.50e+05

2007 10 18 1500 54391 54000 0 3.6 433.9 1.70e+05

2007 10 18 1600 54391 57600 0 4.3 449.9 1.73e+05

2007 10 18 1700 54391 61200 0 4.5 483.7 1.56e+05

2007 10 18 1800 54391 64800 0 4.3 475.3 2.52e+05

2007 10 18 1900 54391 68400 0 4.7 495.2 2.71e+05

2007 10 18 2000 54391 72000 0 2.8 483.0 3.06e+05

2007 10 18 2100 54391 75600 0 3.9 549.4 5.71e+05

2007 10 18 2200 54391 79200 0 3.9 552.0 5.31e+05

2007 10 18 2300 54391 82800 0 3.3 563.7 5.32e+05

2007 10 19 0000 54392 0 0 3.7 582.8 4.93e+05

2007 10 19 0100 54392 3600 0 3.9 589.7 4.81e+05

2007 10 19 0200 54392 7200 0 4.2 589.2 3.76e+05

2007 10 19 0300 54392 10800 0 4.0 590.8 3.00e+05

2007 10 19 0400 54392 14400 0 4.8 592.5 4.18e+05

2007 10 19 0500 54392 18000 0 4.3 598.8 3.60e+05

2007 10 19 0600 54392 21600 0 3.3 629.6 3.13e+05

2007 10 19 0700 54392 25200 0 2.5 629.7 3.13e+05

2007 10 19 0800 54392 28800 0 2.4 625.2 3.56e+05

2007 10 19 0900 54392 32400 0 3.2 623.0 3.35e+05

2007 10 19 1000 54392 36000 0 3.9 608.0 3.03e+05

2007 10 19 1100 54392 39600 0 5.3 638.3 3.07e+05

2007 10 19 1200 54392 43200 0 4.2 619.9 3.10e+05

2007 10 19 1300 54392 46800 0 2.7 637.5 2.58e+05

2007 10 19 1400 54392 50400 0 1.9 644.5 2.35e+05

2007 10 19 1500 54392 54000 0 1.8 628.3 2.14e+05

2007 10 19 1600 54392 57600 0 1.6 612.6 2.10e+05

2007 10 19 1700 54392 61200 0 1.9 616.4 1.87e+05

2007 10 19 1800 54392 64800 0 1.1 616.6 2.17e+05

2007 10 19 1900 54392 68400 0 1.3 618.7 1.97e+05

2007 10 19 2000 54392 72000 0 1.0 634.5 1.80e+05

2007 10 19 2100 54392 75600 0 1.0 618.3 1.80e+05

2007 10 19 2200 54392 79200 0 1.2 618.5 1.80e+05

2007 10 19 2300 54392 82800 0 1.2 633.2 1.89e+05

2007 10 20 0000 54393 0 0 1.3 657.1 1.77e+05

2007 10 20 0100 54393 3600 0 1.4 669.9 1.76e+05

2007 10 20 0200 54393 7200 0 1.4 658.3 1.64e+05

2007 10 20 0300 54393 10800 0 1.1 645.9 1.80e+05

2007 10 20 0400 54393 14400 0 1.0 642.2 1.82e+05

2007 10 20 0500 54393 18000 0 1.1 640.4 1.71e+05

2007 10 20 0600 54393 21600 0 1.0 634.0 1.72e+05

2007 10 20 0700 54393 25200 0 1.0 626.5 1.63e+05

2007 10 20 0800 54393 28800 0 1.1 625.6 1.93e+05

2007 10 20 0900 54393 32400 0 1.4 626.5 1.93e+05

2007 10 20 1000 54393 36000 0 1.6 629.5 1.75e+05

2007 10 20 1100 54393 39600 0 1.0 644.9 1.59e+05

2007 10 20 1200 54393 43200 0 1.2 665.6 2.06e+05

2007 10 20 1300 54393 46800 0 0.9 671.5 2.31e+05

2007 10 20 1400 54393 50400 0 1.2 673.9 2.17e+05

2007 10 20 1500 54393 54000 0 1.4 658.0 1.93e+05

2007 10 20 1600 54393 57600 0 1.3 656.0 1.69e+05

2007 10 20 1700 54393 61200 0 1.2 640.9 1.80e+05

2007 10 20 1800 54393 64800 0 1.1 637.2 1.71e+05

2007 10 20 1900 54393 68400 0 1.0 620.6 1.48e+05

2007 10 20 2000 54393 72000 0 0.8 602.8 1.45e+05

2007 10 20 2100 54393 75600 0 0.8 597.4 1.37e+05

2007 10 20 2200 54393 79200 0 0.8 584.7 1.33e+05

2007 10 20 2300 54393 82800 0 0.9 577.6 1.27e+05

The red bit is hot, fast and has lots of protons, so I think it is possibly part of the same event that may have caused the comet to brighten. I am sure that the experts will soon tell us!

[snowsure]

Problems:

All our satellite data...

A magnificent, complete reply Chris. However, it makes me wonder why we haven't had similar brightenings from other comets that have coincided with a CME.

I remain, despite your sterling efforts, open minded regarding this event.

[Weather-history]

We seem to be going through a good era for naked eye comets since 1996. From 1976-96, naked eye comets were almost completely absent. Even Halley was a huge disappointment.

Edited October 27, 2007 by Mr_Data

[ukmoose]

This is going around the wires, out of nowhere a 14th magnitude periodical comet called Holmes that is currently on view has dramatically brightened to magnitude 3 and is now naked eye in Perseus.

http://www.space.com/spacewatch/071025-comet-holmes.html

I've only just spotted this Mr D - the link is very interesting, Thanks for bringing it to our attention. Not sure the weather is going to play ball to give us a chance to see it though.

Moose

[Chris Knight]

This comet is an interesting beastie - one of the Jupiter group:

check out the info on JPL interactive 3D orbit applet:

http://ssd.jpl.nasa.gov/sbdb.cgi?soln=SAO%...orb=1;log=0#orb

Apparenly discovered in November 1892, 115 y ago and had another similar outburst then!

another forum with links:

http://www.bautforum.com/astronomical-obse...-eye-comet.html

I don't know about the solar wind influence, really, it is just conjecture. I would guess that close shaves with objects in the asteroid belt could just as reasonably cause a rearrangement of the surface to facilitate an episode of outgassing, it's just the amazing change in luminosity, together with the spectral lines, meaning ionisation that has me guessing that the SW is involved.

Maybe it will have another outburst in the next 24h if the solar wind is favourable

[Weather-history]

Saw it last night through breaks in the clouds. It was pretty clear even with the glare of the moon and some light pollution.

[Godot]

I finally got to see it tonight. Photos here, here and here.

[snowsure]

I finally got to see it tonight. Photos here, here and here.

Nice pics Goatherd. I also got to see this with my own scope for the first time tonight. Very impressive it is too. The cloud is building now but, if you haven't seen it yet, get your binoculars out and go looking!

[Weather-history]

Looks like a planetary nebula in some ways. I wonder how large the coma will get?