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Nova in Perseus

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garypoyner's picture
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Nova in Perseus

It would seem that a unique event is now occuring in Perseus.  V392 Per, a dwarf nova with a range of 14.0-17.0V is now shining around magnitude 6.5 after undergoing a classical Nova eruption.  To my knowledge this phenomenon has never been seen before.

The discovery was made by Yuji Nakamura, Kameyama, Mie, Japan on a CCD frame taken on 2018 Apr 29.4740 UT (limiting mag 12.5) using a 135mm f4.0 lens. 

The position is   RA 04 43 21.38  Dec +47 21 25.9 (2000.0)

Further details on ATel 11588 can be seen here .  Robin Leadbeater has a spectrum here

A chart can be created with the AAVSO VSP, but you will need to show a wide field for the bright comparison stars (the ones used previously for V392 Per are all suited to it's faint DNe type outbursts).  

Gary

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Nova!

Thanks for pointing this out - and I see Denis has put an image of the nova and field on his member's page. Time to get my StarAnalyser out!

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Nova alert

Thanks for the alert Gary. Typical however, we've had loads of rain here in East Anglia in the last few days and still raining. If it does stop we'll still have a full moon to take the edge off. Hopefully it will still be shining promnently when conditions improve.

Andrew

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Image centred on 20:58 UT, 30 April 2018

Wow, it is bright!

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Spectrum evolution

Spectra showing evolution between last night and tonight

(ALPY 600  R~520)

Robin

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Great stuff. Now if only we

Great stuff. Now if only we could get a clear sky in the southeast of England...

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Fading

Last nights (April 30) observations show V392 Per has faded by nearly a magnitude; 7.3-7.4 through the course of the evening.

Stick with it though, as the decline is usually pretty interesting - especially if it has an active transition phase.

Gary

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Nova Persei 2018

Yes, Gary - our witnessing a dwarf nova becoming a classical nova is unprecedented. And I see Robin's spectrum shown on the ARAS Spectroscopy Forum:

http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=2015

was of particularly high quality (given plenty of photons from a 6th magnitude source) and managed to report ahead of the professionals. Robin's contribution was duly acknowledged by Wagner et al. in ATEL #11588:

http://www.astronomerstelegram.org/?read=11588

My request is - Can someone put a short news note out on the BAA frontpage so as to alert the membership, etc.?

Richard

 

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Not unique

So, the Nova outburst of V392 Per is not unique after all.  I found this interesting article  describing Nova Cen 2009 (V1213 Cen) and it's pre-Nova outbursts. 

One other candidate (V1017 Sge - Nova Sgr 1919) was found to have a DNe type outburst 18 years before the Nova outburst and two following it, but although the light curve shape is the same as a classical Nova, V1017 Sgr is actually a symbiotic star and not a classical dwarf novae.

Maybe not unique then, but it's still extremely rare - and interesting!

Gary

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After a nice day the evening

After a nice day the evening was very hazy with a lot of cirrus but I did manage to get a picture of it in a small gap. The attached is a single 15s exposure at ISO800 with a 100mm f/2 lens at f/2.8. Capella is the bright star at lower left. The nova appears very red on this image.

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Picture

Excellent picture Nick, shows it off really well.

Andrew

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Low Resolution Spectrum

I managed to get a 'quick look' spectrum last night as the clouds parted and before the nova went behind a tree!

I used my 4.5 inch F/5 Newtonian with a 12 degree objective prism to image a 2.5 x 1.3 degree field containing the nova.  It stands out clearly from the other stars in the field.  Even with my un-modified Canon 550D DSLR the red H alpha emission is clear and explains the red colour of the nova seen in other images.

The bright star at top right is mag. 5.6 SAO39688, spectral type A0, showing H beta and H gamma lines.

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Mike. Very nice. That H-alpha

Mike. Very nice. That H-alpha emission is very strong.

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Visual observation last night

I had visuals on it last night from 22:15 hours to 23:15 hours. It was a balancing act between the sky getting darker as astro dark approached (22:58) but getting brighter as the almost full moon rose higher (moonrise 21:52) combined with target getting lower! I first detected it (surprisingly) in 7 x 50 binoculars just getting to grips with the field as I was going to use small fully manual scopes on Alt-Az mounts so I could move around to clear horizon obstacles. I then switched to a 72mm ED with full erecting prism and various powers starting off with a 24mm Panoptic giving x18 with a 3.8 deg FOV. I then switched to an Intes-Micro Alter 500 127mm F10 Mak-Cass for more light gathering. I didn't see the mag 9.3 star (SAO39704) very near to it in the bins but I did in the 72mm and 127mm scopes. It was much brighter than the mag 9.3 star and I thought it had a hint of a red tint to it but very difficult to be sure on faint-ish objects. I then compared it to nearby stars SAO 39724 (mag 7.26) and SAO 39696 (mag 7.97), these were the two stars at the bottom of the Rhombus pattern. It wasn't quite as bright as the m7.26 star but brighter than the 7.97, I put it at a 1/3 to 2/3 so estimated the brightness of V392 at mag 7.50.

Great fun, Andrew

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H alpha dominating the spectrum

Here is tonight's spectrum. H alpha is really dominating the spectrum now as the continuum drops away. About 1/3 of the total flux in the visible range is now from H alpha.

Robin

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Halpha

I took some frames through the StarAnalyser 100 this evening. I’m pleased to see that my spectrum looks very like yours - the expert’s - but of course mine is lower res. The Halpha emission was indeed striking in the images!

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Flux calibrated spectra

Here are my three spectra calibrated in absolute flux (using V mag values from the AAVSO database) rather than relative to the continuum. It is interesting to see how the peak flux at H alpha remains constant as the continuum falls away.

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V 392 Per

Had another good visual view last night. I reckon it's dropped by about a magnitude from previous night.
Observed it with my 12" D-K Mewlon and my large 28 x 110 binoculars. It was just detectable in the 11 x 70 finder. It was distinctly reddish in the 12" but too small a FOV to make magnitude comparisons. The best overall view was in the 28 x 110 binoculars which I used to make magnitude estimates.
2nd May 2018, 21:30 hrs UT:Now dimmer than SAO 39696 (mag 7.97) but brighter than SAO 39704 (mag 9.3) In a ratio of 4 parts I put it -1 and +3 roughly = mag 8.3. Looked slightly brighter than SAO 39710 (mag 8.77) but midway between SAO 39734 (mag 8.88) and SAO 39742 (mag 8.14) which equates to approx mag 8.5. I would plum for mag 8.5.

Forecast looking good for the weekend so an opportunity to see this plummeting each night, it will soon be fainter than the mag 9.33 star next to it. Great stuff.

Andrew

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Bang on

We'll make a VS observer of you yet Andrew.  Give those fuzzies a break for a bit!  ;-)

Your estimate is in good agreement with other observers - fading quite quickly now.  My own was 8.5 last night with 10x50B from dear old Brum!

Might have to take my life in my hands and observe from a nearby hill when it gets a bit lower.  Bit dodgy up there of a night time, but needs must.  Can I sneak out without the wife finding out though?  Just as risky...

Gary

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Bang on & faint fuzzies

:-)

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Prof Steve Shore puts the event into context

The ARAS spectroscopy group have a symbiotic relationship with Prof Steve Shore at the University of Pisa. (We take spectra and he explains what they mean).  Today he puts this event into an astrophysical context.

http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=2015&start=30#p10615

Cheers

Robin

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Prof Steve Shore puts the event into context

Thanks for sharing the link to Steve Shore's explanation - it's a really interesting read.

And congrats on getting the timely spectrum!

Go well!
Jeremy

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V392 outburst

I imaged it last night with a Canon 60Da (105mm lens) and LPR filter - very red in the single frame (see inset).  The magnitude is effected by the CCD and filter response and I made it about 8 - Sorry not very scientific, but clearly a remarkable object.

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My picture

I removed this comment because the picture was uploaded OK

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V392 per

The Gaia DR2 parallax puts this Binary at 12675L/y so at 6.2m its absolute magnitude rivalled Rigel  for a while at -6.75M, 43,000 times the luminosity of the sun. What a view and a surprise! that would have been for any life bearing planets  at 32.6 L/y or nearer!

Peter

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Bang on & faint fuzzies

On Denis' Member Page entry for May 2 a typo describes V 392 Per as a 'comet', so keep observing!     :-)

Clear skies,

     Alex.

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So it does. Denis is a very

So it does. Denis is a very dedicated comet observer not so used to imaging bright point sources that don't move...

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Bang on & faint fuzzies

We're all likely to produce unintentional typos after a long observing session! 

I used my Watec video camera and 50mm f/1.7 Vivitar SLR lens to record the field of V392 Per. I'll add a pic to my Member Page later this weekend.

Come along to Newcastle tomorrow. My talk won't be flawless but I hope there's something in there of interest.   :-)

    Alex.

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Nova V0392 Per on Wednesday

Nova V0392 Per on Wednesday evening 2nd May. Just had a chance to process my rather low quality spectrum taken under difficult conditions. Anyway, the hugely doppler-broadened hydrogen and helium emissions are very clear especially of course the towering Hα emission. A central, narrow peak at the normal rest wavelength is emerging from each broadened emission. This narrow peak seems to be becoming more pronounced in the most recent spectra on the ARAS forum http://spectro-aras.com/forum/viewtopic.php…

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V0392

We have a star party this evening, and thankfully the skies are clear.

I will have a look at this and report back.

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V392 Per

Observations for May 5  21:31 in the VSS database indicate the Nova as increased in brightness to 7.34m

Peter

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rebrightening

I suspected as much.  It looked noticeably brighter in the spectrograph guider but the moment I moved it onto the slit, the mist rolled in so no spectrum last night.

Robin

EDIT: No sign of rebrightening in later data in the AAVSO database though. I am now kicking myself for not grabbing the guider image

EDIT:  I see the 7.3mag in VSS was in I. My guider camera is unfiltered and the nova is very interstellar reddened so probably explains why it looked so much brighter to me than the nearby Vmag 9.3 star

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No brightening

Visual was 8.8 last night (May 5.9).  

Gary

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V0392

Finally, a clear sky. And a nova.

I saw V392 visually using a 24mm Panoptic in my Celestron C9.25. FOV 0.69, magnification x97. From Teggs Nose Country Park

The Nova was very easy to see next to 93 Per. I thought N392 looked reddish to my eye's.

To confirm I had indeed found it. I compared the eyepiece view with a picture on the Sky and Telescope website.

Macclesfield AS held a public star party last night. And we were fortunate to have this nova on view. A lot of people asked the same question. What is a nova? 

I was able to explain to the best of my knowledge what it was.

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H alpha falling

Tonight's spectrum (in absolute flux) compared with previous spectra. Although the H alpha line remains strong in the spectrum relative to the continuum,  when expressed in absolute flux  the line intensity has  fallen significantly over the past 4 days.

Robin 

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Brilliant work. These

Brilliant work. These absolute spectra really show the evolution well.

Do you think physics will ever adopt SI units? It is one of the significant differences between physics and engineering and I have to keep looking up the scale factor between ergs and Joules. I suppose CGS is better than BTUs and feet...

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Units

Yes, astronomers in particular seem to be a pocket of resistance against the forces of SI. 

In my other life in the paper industry, the US measure the weight per surface area of paper in pounds per ream (now generally 500 sheets) where the specified sheet size depends on the type of paper you are taking about. So 20lb newsprint (36x24 inches) is much lighter than 20lb bond paper (22x17 inches) for example !

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V392 evolution 2nd-6th May

Robin,

I'm not sure of the best way to compare my two relative intensity spectra but here's what I did for my spectra from 2nd and 6th May...

Cheers

Hugh

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relative and absolute flux

Hi Hugh,

OK so I assume your two spectra are scaled relative to the continuum over some common wavelength range? From the AAVSO data however, the V band total flux  has reduced by ~0.4 mag between the two dates (I assumed values of 8.3 and 8.7) which means the amount of flux in the emission lines in the later relative flux calibrated spectrum is exaggerated.  To calibrate in absolute flux I used a tool in ISIS ("Tools", "Spectra 3" , "Flux density conversion" ) which integrates the flux in the spectrum over the standard (Bessel) V filter passband and uses the photometric V magnitude (from AAVSO) to rescale the spectrum in physical flux values.  (Using the relationship between V mag and physical flux established for the standard star Vega). There are some approximations/assumptions in this method I believe and I think David Boyd has published a more rigorous method somewhere where he uses his own photometric brightness measurements but I think it should be  good enough to show the trends.

Cheers

Robin

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Unfortunately the nova

Unfortunately the nova appears to be too low down from my location !

Also, the SkyX doesn't recognise the name V392 Per or its JO or SON designations. I typed in the RA and DEC coordinates instead, it seemed to track there, but was not visible through the finder scope !

Well done to everybody who got data.

Regards,

Jack

Essex UK

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first paper published

I see there is a paper published on this already

https://arxiv.org/abs/1805.00994

Note the second author's name. Unless it is a pseudonym, he/she just had to be an astronomer !

Robin

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Re: first paper published

Prof. Sumner Starrfield is a computational astrophysicist at Arizona State University, and he's a world authority on cataclysmic stellar events.

Gary

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Googled him

Hi Gary,

Indeed. I  had not come across the name before and googled him after I posted. I wonder if his name had any influence on his choice of career ?  I decided at an early age that my traditional family occupation was not for me ;-)

Robin

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Nominative determinism

I am perhaps extending this frivolous sidetrack beyond its natural life ... notwithstanding this, the New Scientist for a long time ran letters on nominative determinism in its Feedback section. Weedon and Splatt published lots of urology research.

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Update on nova mag

V392 Per is noticeably dimmer than the nearby TYC star now. Here's an image from this eve (13 May) - UV/IR block only. Time in filename is UT. I have measured the mag as 9.8 (CV).

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Fading

I had it at 10.0 visual last night - my small 22cm dob (stopped down to 5cm) balancing on a garden table, desperately trying to get over the roofs.

The Nova should be entering it's transition phase any time soon (about 3-4 mags from maximum), but some fast nova (and some slower ones too) simply pass through it without any visible change to the decline, whilst others show oscillations and the dusty ones fade and re-brighten before fading again.  The rarer activity is to re-brighten before fading to it's post nova quiescence.  What's this one going to do?

Gary

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Light curve

I’ll be looking as often as I can. I had trouble getting access to this patch of sky too!

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I have been able to get

I have been able to get observations on a good few nights since outburst occurred. I can get to the area of sky where it is located but it is in bright twilight for me here at Tarbatness. The 15th mag companion star just to the north of the nova is now showing on my images. Just to blow my own trumpet I got a reference in that Darnley/ Starrfield paper as being one of the first to report photometry. I seem to have good luck with getting onto nova quickly after outburst is announced.

https://arxiv.org/abs/1805.00994