Patrick Schmeer alerted us via several lists and facebook groups that K. Itagaki discovcered a bright possible nova in Delphinus:
PNV J20233073+2046041 2013 08 14.5843* 20 23 30.73 +20 46 04.1 6.8 U
Discovered by Koichi Itagaki, Yamagata, Japan, using 0.18-m reflector + unfiltered CCD. This Nova was confirmed on the frames taken on August 14.750 UT using 0.60-m f/5.7 reflector + unfiltered CCD after discovery. Then CCD magnitude is 6.3. Also nothing is visible at this location on his past frames (limiting mag.= 13.0) taken on 2013 August 13.565 UT.
Prelim. estimate from my images now is 6.2 +-0.1mag, so not that much brighter than the 6.3 mag reported in the confirmation (see link in thread starter) for August 14.750 UT. Looks like clouds are closing in on me now :-( Good luck everyone CS HB
Nova Del is apparently still rising, judging by earlier reported mags and my two observations of this evening.
Aug. 15.0576 5.9
Aug. 15.1431 5.7
I was wondering about dstance and possible peak magnitude we could expect from this. I found a distance estimate of 1 Kpc here:http://www.astronomerstelegram.org/?read=5283
Should we expect this to reach N Sco 2007 brightness? (3.9)
Or is N 1975 Cyg brightness in the realm of possibility? Too early to tell?
According to this http://en.wikipedia.org/wiki/V1500_Cygni; Nova Cyg 1975 was twice as far away (If the above 1Kpc estmate is reasonable.
Does anyone know what kind of nova we have? (Fast , Slow, He, Fe)?
If so how do you know?
Hi Andy. Thanks so much for your thoughtful questions.
Actually, the authors of ATel 5283 did not quote a distance -- they
just used a fairly arbitrary distance-scaling of 1 kpc to report an
X-ray luminosity (as is often done).
The E-Nova collaboration has triggered radio observations, and once
these are performed, they will provide a good first distance estimate.
This is because the radio flux density is proportional to the size of the
ejecta, modulo the distance, and we know the size of the ejecta from
published velocities muliplied by the time since the start of the
Once we have a good distance estimate, we will be able to have a
better sense of how bright this nova might get (assuming that it has
not already started to fade by then!).
All the best, from Chalkidiki, Greece,
On August 16, jeno mentioned that:
The E-Nova collaboration has triggered radio observations, and once these are performed, they will provide a good first distance estimate. This is because the radio flux density is proportional to the size of the ejecta, modulo the distance, and we know the size of the ejecta from published velocities muliplied by the time since the start of the eruption.
Is there a distance result from this approach yet?
Hi David, and Bikeman.
In asking about the distance to V339 Del that one infers from radio observations, you raise a delicate issue. You might notice that in ATel #5382, we report on the radio detection of V339 Del, but we do not say anything about a distance. That is because something strange is going on. The radio flux is quite low, suggesting that either: 1) the distance is surprisingly large for such a bright nova; 2) that there was a delay between the thermonuclear runaway that triggered the nova and the expulsion of material from the system; or 3) that the ejecta were initially too cold to produce radio emission. We are waiting for additional data (at all wavelengths) to try to determine which of these options is correct.
From optical spectroscopy, Steve Shore and collaborators suggest that the distance is 6 kpc (ATel #5409).
Fascinating re: ATel #5382.
Another question I have is: where did the mag 16.9 minimum recorded on VSX come from? There was discussion earlier in this thread about pre-nova mags being captured on Perseid meteor images, for example. Was this 16.9 value taken from something like this or a previous "survey" plate or DSS or ...?
This is already a big deal, and may even be a bigger deal.
Playing with this Magnitude calculator and plugging in numbers: http://www.1728.org/magntudj.htm
Using 1Kpc = 3200 LY as from http://www.astronomerstelegram.org/?read=5283
From wikipedia and cited paper----Common peak Absolute mags for classical novae are what they call bimodal. Most are -7.5M and a second common brightness is -8.8
Robert, Gilmozzi; Della Valle, Massimo (2003). "Novae as Distance Indicators". In Alloin, D.; Gieren, W. Stellar Candles for the Extragalactic Distance Scale. Springer. pp. 229–241. ISBN 3-540-20128-9
Using the above Absolute mag calculator, I get 2.5V peak for the -7.5group and a whopping 1.2V! for the -8.8 group! (Extinction not accounted for)
This sort of rare thing , seems unlikely to me. The principal of Occum's Razor would suggest that this may too optimistic. I make some assumptions. Info coming out is only as good as data going in.
Hi again, Andy. It looks like you are finding all the right references and doing all the right calculations!
Now, we just need to get a good distance and extinction... :)
An interesting nova and the first in a long time that I recall seeing distinctly with the unaided eye. I concur with others that the nova continues to slowly brighten. I obtained 4.8 with the unaided eye using multiple comp stars on August 16.0743UT, a full magnitude above what I got last evening. The nova's slow, but steadily continuing increase in brightness hints at a "relatively slow" nova to me and I will be extremely interested to see more pre-discovery magnitudes come to light.
Well skies have cleared now here in Ireland, I've just taken a look at it with my 15x70mm binos, visually I now estimate this nova at magnitude 4.8, I can easily see it with the naked eye under excellent clear skies.
I hope that you are right and this gets even brighter !
Observing through hazy skies in Denver, Nova Del appears brighter than nearby 4.8 mag star, 29 Vul.
Nova has orange appearance (H-alpha) and may appear slightly brighter (Purkinje effect). Observation at 2145MDT 15-Aug-2013 = JD 2456520.6645. SVR.
Imaged last evening with iTelescope T18 in V for 90 seconds.
V = 6.243, with error = 0.001, airmass = 1.0782. Check star=98, Comp star = 100. All data from VPHOT.
Tried to get a nice color image this morning but everything was down...I'll try again later.
Also will try to image over the next several days/weeks to see what happens.
What has surprised me greatly regarding this nova is the lack, at least so far, of almost any pre-discovery observations. We have just gone through the peak of the Perseid meteor shower occurring during a virtually moonless period. One would usually anticipate that large numbers of amateurs would have been out taking wide-field images of the sky in hopes of capturing meteors. Cetainly, many would have covered this region of the sky. Yet, all we seem to have are two strongly conflicting datapoints pre-discovery so far. And where are the reports from those known to be carrying out amateur nova photo patrol programs this time?
I do appreciate that it is still early, but past such events generally have quickly produced a number of early sightings. Cetainly, the nova's observed behavior so far could suggest that its rise in brightness in the days just prior to discovery may not have been as abrupt and steep as might have first been assumed. Perhaps over the coming weekend, as folks have an opportunity to go over their Perseid images more, some new information will surface?
In the meantime, I think we may be in for quite a show from Nova Del.
Frans Van Loo (VNL), Genk, Belgium, has captured the field on Aug. 13th at 23h05m 25 s UT using a Nikon D3100 DSLR + 18-55mm zoom lens at 18-mm-f.l. in the course of the Perseid observations.
His image shows the nova slightly brighter than the image background. Although a decent measure is impossible, the brightness estimated from this image is about magnitude 8. The 8th magnitude star just NW of the nova is also visible. Frans did report his observation to the AAVSO and is shown in the LCG, but is indeed conflicting with the ~5.2 observation which is also shown.
Another image captured by Guiseppe Cannonaco, Genk, Belgium, has been taken on Aug. 13th, at 20h41m53s does not show the nova. The limiting magnitude of the image is however about magnitude 7.5.
I am wondering whether the ~5.2 magnitude datapoint shown in the LCG has a typo in the date or magnitude.
We are also eagerly looking forward to more pre-discovery images. Indeed, one could expect that other observers of the Perseid meteor shower have captured the area.
Eric Broens (BOS)
[quote=BRJ]What has surprised me greatly regarding this nova is the lack, at least so far, of almost any pre-discovery observations. We have just gone through the peak of the Perseid meteor shower occurring during a virtually moonless period. One would usually anticipate that large numbers of amateurs would have been out taking wide-field images of the sky in hopes of capturing meteors. Cetainly, many would have covered this region of the sky. Yet, all we seem to have are two strongly conflicting datapoints pre-discovery so far. And where are the reports from those known to be carrying out amateur nova photo patrol programs this time?[/quote]
I've taken some pictures from 13/14 August taken at 21:20 (GMT) and I couldn't find this Nova. It was fainter than 10.2 mag. at that time and I added this observation to AAVSO database.
I've found some more pictures (where Nova's position was close the edge of photo) taken 10 minutes later and Nova was fainter than 10.6 mag. I'll add this to the database too, might be useful.
Cristovao Jacques (Brazil) took an image in 2013 Aug. 14.095 UT and N Del was fainter than 11.2 , using Tycho-2 comps.
A crop animated gif, including another image taken in 2013 Aug. 17.089 UT, is available at this link: http://www.ceamig-rea.net/nova/nova.gif
The whole animated gif is at link (3 Mb)
With so many attention given to the field around Nova Del 2013, I was wondering whether people here have suggestions for scientifically interesting near-by targets of opportunity, especially for DSLR photometrists, but also for binocular observers. E.g. my exposures cover 20 deg x 15 deg so it would be a shame to ignore any interesting "bycatch".
Any suggestions, also for the time of decline of the nova when we will have to make deeper exposures ?