Possible bright nova in Centaurus - PNV J13544700-5909080

[malclocke (Malc)]

Magnitude seems to be plummeting now. Just managed to get a peek at it through the clouds tonight, and I'd say it's dropped to between 4.5 and 5.

[Jon (Jonathan)]

Originally Posted by malclocke

Magnitude seems to be plummeting now. Just managed to get a peek at it through the clouds tonight, and I'd say it's dropped to between 4.5 and 5.

Wow! I wonder if it will brighten again?

Clouds here now, as for the last three days. I've got the alarm set for 3.30 just in case ...

[Merlin66 (Ken)]

Still under clouds here in Melbourne, latest lo-res spectra infer He emission....

[RichardJ (Richard)]

First clear morning for a few days. Could only just barely make it out naked eye under my suburban moonlit sky.

Through the binoculars I thought it had a yellowish hue.

RichardJ

[Jon (Jonathan)]

Originally Posted by malclocke

Magnitude seems to be plummeting now. Just managed to get a peek at it through the clouds tonight, and I'd say it's dropped to between 4.5 and 5.

My photometry of his morning had it as V=4.71. So you nailed it, Malc :-)

[malclocke (Malc)]

Originally Posted by Jon

My photometry of his morning had it as V=4.71. So you nailed it, Malc :-)

I don't know if an error range of half a mag can be described as nailing it, but thanks

[Jon (Jonathan)]

Originally Posted by malclocke

I don't know if an error range of half a mag can be described as nailing it, but thanks

The way this baby has been jumping up and down in magnitude, I think it's pretty good. :-)

Before I measured it, I did a visual estimate. I had it as somewhere between mag 4 and mag 6.

One would have to think it will drop again tonight. Maybe I should open a book on it?

< 4: 10/1
4-4.5 5/1
4.5-5 7/4
5-5.5 2/1 on
5.5-6 2-1
6 <. 3/1

[Rob_K]

Image of the nova from last night attached. Flick from one pic to the other! Also, I've added another spectrum to the other thread.

Cheers -

[Shark Bait (Stu)]

0145 hrs AEST Wed 18-12-2013 (1545 hrs UT Tue 17-12-2013)

Overcast conditions have not allowed for observations over the last couple of days. Still having to wait for clouds to pass in order to compare it with other stars.

Unaided eye - not seen, but I am under the Brisbane light pollution dome and it is almost Full Moon.

7x50 Binoculars - there is a dramatic drop in the brightness of Nova Cen 2013. When compared to nearby stars it looks to be around Mag 4.8 with no obvious colour.

It will be interesting to see if my estimate agrees with that of others.

[cometcatcher (Kevin)]

I took a peek this morning. It does seem fainter than yesterday. Rough as guts guess around mag 5.

[Shark Bait (Stu)]

0130 hrs AEST Thurs 19-12-2013 (1530 hrs UT Wed 18-12-2013)

Essentially a clear sky this morning although still having to wait for some thin cloud to pass in order to compare it with other stars.

Unaided eye - thought that I managed to spot it using averted vision but I could not repeat the exercise so it was probably a case of wishful thinking. I am under the Brisbane light pollution dome and we are just past Full Moon.

7x50 Binoculars - Nova Cen 2013 appears to have an apparent magnitude of 5.0 when compared with nearby stars. There is no obvious colour to my eyes.

[Jon (Jonathan)]

Measured V Mag at 5.03 this morning. A steady decline.

[Shark Bait (Stu)]

0300 hrs AEST Fri 20-12-2013 (1700 hrs UT Thurs 19-12-2013)

A clear, still sky this morning making it easy to compare Nova Cen 2013 with other stars. Brisbane's light dome is not obvious due to the 95% Waning Gibbous Moon.

Unaided eye - Not Seen

7x50 Binoculars - Nova Cen 2013 is between Mag 5.3 and Mag 5.4 this morning with no sign of colour to my eyes (yesterday it was at Mag 5.0). At the moment, it looks to be on par in brightness with HIP66849 (Mag 5.37) which is circled in purple on the attached Starry Night screen grab. I am using SN Enthusiast so I cannot plot the location of the Nova itself.

[cometcatcher (Kevin)]

Looks a little pinkish this morning. Strange that the Ha is very strong.

Full spectrum Nikon 70Ds, 7x1 minute subs at ISO 400, Baader UV/IR cut filter and Kson ED80 at f5.5.

[glenc (Glen)]

Nov Cen is a about mag 5.2 or 5.3 this morning. I compared it to mag 5.4 HD 118978 using 7x50 binoculars.

[cometcatcher (Kevin)]

A little deeper pic with 15x1 minute subs.

[Jon (Jonathan)]

Originally Posted by cometcatcher

Looks a little pinkish this morning. Strange that the Ha is very strong.

This is a stage you expect to see in novae. A whole bunch of hydrogen has been flung into space from the surface of the white dwarf in the initial explosion, streaming out at around 1000 km/s. So by now, this cloud is around 1 AU in radius. It's being energised by intense radiation from the nova, and so is emitting at the Ha wavelength. As well as FeII - rap there are significant amounts of ionised iron in the ejects from the nova.

At this stage, IIRC, we can only see this thick glowing gas cloud - it's obscuring the surface of the star itself.

[cometcatcher (Kevin)]

Ah so we might see a little planetary nebula around it at some stage?

[Merlin66 (Ken)]

A high probability!

[cometcatcher (Kevin)]

Nice and clear this morning, pity about the moon and mossies.

A couple of shots this morning through the ED80 posing next to Hadar - Beta Centauri. The first is 25 minutes worth of subs with a full spectrum Nikon D70s + Baader UV/IR cut.

Since the nova is belting out heaps of Ha, here's a comparison through the same scope. This time with a 30nm Ha filter. It's certainly brighter in Ha than visible.