Considerable brightening of Gyulbudhagian's Nebula (PV Cephei)

[reiner]

Gyulbudaghian's Nebula around the young star PV Cephei is an FU-Ori star, short Fuor, which have extreme outbursts of up to 6 mag. While Gyulbudhagian's Nebula was an easy target even for smaller scopes ten years ago, it became considerably more difficult later.

_PV_Cep.jpg

Here is a sample of DSS images showing the variability of the nebula
PV_Cep_vari.jpg

I have monitored PV Cep and the nebula (or better its visual non-existence :-) ) over the past five years. My notes were as follows (with 22"):

09/2008: nothing visible, neither star nor nebula
07/2010: dito
08/2010: star was suspected several times, doubtful
10/2010: indirectly, a small extended object was suspected, extremely difficult
10/2011: star very difficult, but with certainty. No nebula
08/2012: nothing.

Last week, an image was posted on Cloudy Nights, on which the nebula appeared to have brightened.

http://www.cloudynights.com/ubbthrea...Number/5996754
Note that the image is mirrored.

So I tried it Thursday night under alpine skies in the Austrian Alps. And surprise, the nebula was immediately visible without even locating its precise position. It appeared as an easy direct vision object, larger than expected (a bit less than 1') and fan-shaped (only one lobe is visible of this bipolar nebula, the other is obscured by the dust envelope around the star). The fan was of even surface brightness and PV Cephei could not be resolved at the tip of the fan.

Here is a finder chart of this Young Stellar Object
http://www.reinervogel.net/pdf/PV_Cephei.pdf

More about this type of objects and Young Stellar Objects in general is on my website
http://www.reinervogel.net/YSO/YSO_e.html

[Uwe Glahn]

Reiner,

perhaps you know my attempts to catch PV Cep (German side) In English:

05/2009 - 16", no sight
09/2009 - 16", extremely faint glow suspected
10/2009 - 16", two observer suspected faint glow
09/2011 - 27", small and faint plob with stellar peak at the S end, can hold it with averted vision

Thanks for the reminder, I have to try it again.

[reiner]

Hi Uwe,

your list looks very familiar ;-)

I guess the sequence of many negative and two semi-positive observations in my list not only reflects the variability of PV Cep, but to a similar extent that of the observing conditions for a threshold object.

I observed it again last night at my nearby local observing spot trying to precisely see the edges, with the eastern edge being easier than the other side. Again, the star itself was not visible only the nebula.

[hajuem]

Hi Reiner

Do you have special night at Thursday to Friday at the Bielerhöhe!! Very interesting observation of PV Cep!! The outburst is very impressive!!
I hope for good observation-conditions in the next days!!
Thanks for that!!

Clear Sky Hajü
www.astromerk.de

[Uwe Glahn]

Reiner,

Friedl and I tried the nebula with our 16" and 27" last night from a alpine place with very good transparency.

With 16" it was still faint, but the nebula could easily hold with averted vision. We could not detect any form, it remained as a diffuse glow. With 27" it was a direct vision object. Like you said it seems like a fan shaped nebula. I suspected a shorter but brighter W edge with a spot in it to the S. The star was not visible. All in all not easy to detect the correct form.

[Howard B]

I had a look last night (21.52 SQM, great transparency, terrible seeing) and was surprised how bright G's Nebula is now - I think it's the brightest I've ever seen it. Also, it seemed larger and rounder than I remember. No luck seeing PV Cephei though, but the seeing really was bad at the time.

[reiner]

Hi Howard,

I have revisited PV Cephei several times in the past two months. As you, I was not able to see the star.

Here is a very recent image by Leo Bette, a friend of mine here in Freiburg. The image is just luminance and the star is distinguishable from the nebula.

PVCephei_L_integration.jpg

Due to the dust, however, the star is likely to be much redder than the reflection nebula and hence more difficult to detect visually.

PS: Sorry, you can't see the star in the image due to compression by the forum software. Here is a crop of the center, where the star should be visible.
PVCephei_L_crop.jpg

[Howard B]

Thanks for posting these images Reiner, I'll use them the next time I get a chance to observe. Hopefully I'll have steadier seeing and will have a better chance to see the star.

[Steve Gottlieb]

Here's another recent observation of G's nebula that I made in August from the northeast corner of California (SQM 21.6-21.7) with my 24-inch. As noted several times, PV Cep was not seen, but the nebula is relatively easy these days.

Gyulbudaghian's Nebula was immediately picked up at 200x as a faint, elongated glow, fanning somewhat (though not as much as I remember from 2003) and extending NNE for ~25". There was slight brightening at the SSW tip, which contains the obscured Herbig Ae pre-main sequence star PV Cep, but as opposed to the earlier observation, PV Cep was not visible. A box or parallelogram asterism consisting of 4 mag 10-13 star is directly east, including a mag 10.5 star 2.4' ESE.

[Bill Weir]

Oct 8 I finally remembered to have a go at Gyulbudaghian's Nebula with my 20". Years ago from a high altitude site under excellent conditions I made a very iffy observation of the nebula with my 12.5". It was probably about 10 years ago. This time it was at essentially sea level and the SQM reading was only 20.85 as it has been raining lately and there was moisture in the air. On the other hand the seeing was (as it often is here on the southern tip of Vancouver Island) very good. I was at the school observatory a few km down the road from my house.

Once on the field at 180X the nebula was picked up fairly easily. Despite the previous reports I was still quite surprised at how easy it was. The image held as I increased magnification to 320X. Definite fan shape with the tip pointed south. The eastern edge of the fan appeared brighter and slightly cleaner edged. PV Cep was not seen.

I did a very rough sketch on the lined note paper I had with me and then transferred it to some cleaner paper. My sketching skills are a bit unpracticed so the redone sketch remains rather rough. I apologies at the front end for what I'm attaching.

Gyulbudaghian's Nebula Oct 8 2013 - Copy.jpg

Bill

[akarsh]

Do you think I'll have any luck if I try this with my 18" by the end of the month? (Cepheus should still be around, right? although it might not rise high.)