Object of the Week, October 25, 2020 – GM 1-29, HH 215, Gyulbudaghian’s Nebula

[Howard B]

Emission nebula
Cepheus
RA: 20 45 58
DEC: +67 58 30
Magnitude: variable
Size: variable

I had terrible luck finding an object for this week’s OOTW – it took fourteen searches until I found an object that hasn’t been an OOTW in the past*. The search was worth it though, but tracking down this fascinating variable nebula in Cepheus is even more rewarding.

Gyulbudaghian’s Nebula is a variable object, and I’ve seen it as both a bright and obvious wedge of nebulosity, as well as not seeing any trace of it - and this unpredictability is a big part of why I find this object so fascinating.

Discovered in 1977 by astronomer Armen Gyulbudaghian, this reflection nebula is produced by an energetic outflow from the newly forming star, PV Cephei. We see the northern outflow - the opposing southern outflow is hidden by dust – which makes GM 1-29 much the same type of object as much the brighter Hubble’s Variable Nebula (NGC 2261). This HST image shows a remarkable similarity to 2261.

GM-1-29_HST.jpg

Assuming GM 1-29 has properties similar to Hubble’s Variable Nebula, the apparent changes in the nebula are caused by shadows produced close to the newly forming star - PV Cephei in this case - by the rapidly changing conditions near its circling dust ring, while the actual nebulosity stays much the same. Because the nebula is an energetic outflow it’s definitely changing shape, but not quickly enough to produce the changes we see. The rapidly changing shadows projected onto the nebula are what produce the variations.

Here are two observations with my 28-inch scope showing the nebula as completely unseen, with only PV Cephei being visible, and five years later as an easily seen fan of light:

“No trace of the nebula – not the slightest hint. I’ve given the area a good workout using 273x and 408x, where I could see PV Cephei, the illuminating star. Fascinating that there’s no nebula to see now, and I even tried all my nebula filters. 21.95 SQM” (September 2008)

GM 1-29_9_2008.JPG GM 1-29_9_2008_invert.JPG

“After extensive use of averted vision at 408x and 695x I got a couple of pops of PV Cephei at the vertex of GM 1-29’s fan shaped nebulosity. I also glimpsed it as a faint knot so I’m sure I’m seeing what the atmosphere allows right now. 21.52 SQM” (October 2013)

GM 1-29_October 2013.JPG GM 1-29_October 2013_invert.JPG

2013 was the last time I’ve observed GM 1-29, so I don’t know whether it’s visible or not right now. There’s only one way to find out, so…

Give it go and let us know!


*By the way, I did find GM 1-29 was discussed in an Off the Beaten Path forum posting in 2013, but after seven years I’m happy to present it as an OOTW because it’s a variable object. And I really didn't want to keep searching...

[Steve Gottlieb]

You have to love this object -- just for the name! (though we probably need a pronunciation guide)

Two observations ten years apart...

24" (8/5/13): After hearing that Gyulbudaghian's Nebula (GM 1-29) had brightened and was visible again after several years of disappearance (since roughly 2006), it was high on my observing list. I immediately picked it 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.

18" (10/25/03): I was surprised to easily pick up this challenging object at 115x as a very faint, roundish 15" glow. Located 2.5' W of a mag 10.5 star and 4' WSW of a mag 10 star. A distinctive string of stars heads NW from the mag 10 star ending at another mag 10.5 star 7' N of the nebula. At 250x, PV Cephei, the illuminating star, was intermittently visible on or just off the SSW tip of a 20" glow. The nebula fanned out broadly, centered towards the NNE. At 300x, Gyulbudaghian's Nebula was easy and visible continuously with direct vision. PV Cephei appears ~15.5 magnitude and was just separated from the nebula.

[Raul Leon]

Hi, here's my observation from 9/8/2013: Gyulbudaghian's variable nebula aka GM 1-29 in Cepheus ; magnitude : variable size: variable ; was surprised to pick up this object, small fairly bright fan-shaped nebulosity attached to a faint star; no filter used ; I used a 10mm Ethos at 158x with my 14.5 Starstructure Dob f/4.3gyulbadaghian's nebula.jpg

[MikeWiles]

Friend and part-time astronomical mentor Tom Polakis recently completed and posted a time lapse of Gyulbudhagian's Nebula over the last five
years. It indicates that the nebula is currently not visible. Here's a link to his excellent time lapse: https://pbase.com/polakis/image/171103742

Curious, I attempted an observation on October 16, 2020 with my 20" scope and was unable to detect any nebulosity.

[Bill Weir]

It’s funny how everyone is grabbing back into their 2013 bag so here’s mine.
https://rascvic.zenfolio.com/p566114...125e#h3daaa192

If the weather ever clears and once the Moon goes away I’ll have to give it a go.

Bill

[obrazell]

There are some indications it might be coming back https://britastro.org/node/24757

Owen

[Uwe Glahn]

What an interesting back and forth. And very cool time lapse, didn't know it yet. My observation even with 8" are as follows:

5/16/2009 - 16", 180x, fst 6m0+
nothing visible

9/19/2009 - 16", 257x, fst 6m5+
extremely faint glow, not steadily visible, not sure - negative log entry

10/20/2009 - 16", 180x, fst 7m0+
faint star group north visible without problems, even under Alpine skies only a popping 20% of time, laminar, other observer did saw the same

9/30/2011 - 27", 419x, fst 7m0+
with middle EP small, laminar object steadily visible with averted vision, stellar peak at the south end, structureless

8/10/2013 - 16", 220x, fst 6m 5+
faint but direct visible glow without any structure

8/10/2013 - 27", 488x, fst 7m0+
brighter conical nebula, south end brighter, east side better defined and somewhat brighter but shorter

9/05/2013 - 12", 167x, fst 6m5+
direct visible diffuse glow without structure, in comparison to the observation one month ago brighter appearance

2/20/2013 - 8", 160x, fst 6m5+
bright phase is still active, steadily visible with averted vision even with 8", small and without structure

1/29/2016 - 8", 160x, fst 6m5+
nothing visible

8/19/2018 - 27", 419x, fst 6m5+
in the searching eyepiece nothing visible, from 293x up a small and faint glow can bee seen steadily with averted vision, 419x brings out more detail - from bright south end a 1:3 elongated 1' fan to the northeast, somewhat bend with a peak at the northeast end, all details difficult to reproduce because of the faint surface brightness

[Uwe Glahn]

There are some indications it might be coming back

Seems that it does not look that way Owen. Just came in from an observing trip and tried GM 1-29 with my 27-inch. While the searching eyepiece (113x) doesn't show anything, 293x gave a popping of an extremely faint, stellar like peak. Not steadily visible and not structure at all.

[ScottH]

Here's Johnny!
9/28/22 I’ve wanted to see PV Cephei’s nebula (Gyulbudaghian's Variable Nebula, GM 1-29, HH 215) for many year now and have tried with my 10” at least once. In my 16” it was best seen at 191x as an extremely faint but detectable patch of nebula. Still detectable at 150x all the way to 300x. PV Cephei however was not visible. I'm a terrible variable star observer, but now that I have a 16-inch, I plan to look for this nebulae at least once a season to keep tabs on it.

Scott