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Mohan-Mishra3 aka Tilak Nebula is a newly discovered object which is a Potential Planetary Nebula. Sankalp Mohan and Utkarsh Mishra(author) are the two young students from India who discovered this Potential PNe that was lurking in the outskirts of IC 2177. Mohan-Mishra 3 is registered at Planetary Nebula net which is handled by Pascal Le du. PN-G: 225.5-01.9 , Coordinates of Mohan-Mishra- 3: 07:07:51.23 -12:07:50.92

Close up of MoMI-3 Captured by Peter Goodhew

What is a Planetary Nebula?

A planetary nebula represents a phase of stellar evolution that our sun should experience several billion years from now. When a star like the sun uses up all of the hydrogen in its core, it expands into a red giant, with a radius that increases by tens to hundreds of times. In this phase, a star sheds most of its outer layers, eventually leaving behind a hot core that will soon contract to form a dense white dwarf star. A fast wind emanating from the hot core rams into the ejected atmosphere, pushes it outward, and creates the graceful, shell-like filamentary structures seen with optical telescopes.

The term "Planetary Nebula" is actually a misnomer as they are unrelated to Planets.

The first Planetary Nebula to be discovered was "Dumbbell Nebula" in the constellation of Vulpecula in mid-1700s by Charles Messier, famous French Comet Hunter, who noticed its distant faint fuzzy

circular glow and placed it in his catalog to prevent him from mistaking it as a comet. A few years later, a musician turned astronomer named William Herschel gave these objects their name after their resemblance to Planets. In the low resolution telescopes of the day these objects resembled the giant planets like Uranus, Jupiter etc.

As early as January 1779, the French astronomer Antoine Darquier de Pellepoix described in his observations of the Ring Nebula, "a very dull nebula, but perfectly outlined; as large as Jupiter and looks like a fading planet". In those days the nature of these objects was not clear. William Herschel, discoverer of planet Uranus, discovered a Planetary Nebula and named it the Saturn Nebula (NGC 7009).

All planetary nebulae form at the end of the life of a star of intermediate mass, about 1-8 solar masses. It is expected that our Sun will form a planetary nebula at the end of its life cycle. This is a relatively short-lived phenomenon, lasting perhaps a few tens of thousands of years, compared to considerably longer phases of stellar evolution. Once all of the red giant's atmosphere has been dissipated, energetic ultraviolet radiation from the exposed hot luminous core, called a planetary nebula nucleus (PNN), ionizes the ejected material. Absorbed ultraviolet light then energizes the shell of nebulous gas around the central star, causing it to appear as a brightly coloured planetary nebula.

Planetary Nebulae are an important albeit brief (≤105 yr), evolutionary phase in the lifetimes of a significant fraction of Milky Way stars. They are an important tool in our understanding of the physics of mass loss for intermediate-mass stars, the chemical enrichment of our Galaxy, and in turn, its star formation history. PN are ideal test particles to probe the dynamics of the Milky Way and are amongst the best kinematic tracers in external galaxies. The PN luminosity function is also a powerful extragalactic distance indicator. Total number of true, likely and possible planetary nebulae (PN) known in Milky-way is nearly 3000 (2010) A Planetary Nebula is produced at the end of the asymptotic giant branch (AGB) phase, as the red giant ejects its outer envelope in a final stage of copious mass loss termed the ‘superwind’. After the envelope ejection, the remnant core of the star increases in temperature before the nuclear burning ceases and the star quickly fades, becoming a white dwarf (WD). The high temperature of the central star (CS) causes the previously ejected material to be ionized, which becomes visible as a PN, its shape sculpted by the interaction between the old red giant envelope and a tenuous, fast wind from the hot CS.

(Planetary Nebulae: Observational Properties, Mimics and Diagnostics David J.FrewA,C,D and Quentin A. Parker A,)

Story: how did we end up finding it ?

Sankalp and I have devoted great amount of time as a team in finding unknown objects which are still lurking out in the cosmos, our main aim is to discover as many Planetary Nebulae as possible but we also come across many HII regions which are still unknown. I started this last year in May, I spent no less than 10 hours per day searching and understand these objects, sometimes I wouldn't sleep till 3am. My hunger for making discovery was increasing each and everyday but I was still patient and waiting for the correct alignment of the universe! now we have made a list of our findings and submitted recently to Pascal Le Du for analyzing and getting it published on PN net website. Hunting for such objects requires out most patience and guidance in starting, luckily we had our best mates from Germany and France , they do not need much introduction as their work speaks for itself. Their names are Marcel Drechsler and Xavier Strottner ( STDR) both have shown par excellence in finding the hidden treasures of the night sky, They have provided their lot of support to us. Last year a video conferencing session was held between 4 of us, in that we discussed about the strategy tips to finding such objects, Glad to have them onboard. We also want to thank Dana Patchick who has helped us a lot by giving his valuable opinions on many objects. Dana Patchick has contributed around 20 years of his life , he has discovered more than 200 objects and several True PN. Now back to how did we find MoMi-3? While everyone was welcoming the new year on 1/01/2021 Sankalp and I had no time to rest, we were busy in doing analysis of survey's for such objects. We spent hours and hours everyday looking for objects and started compiling list.

DSS Image of MoMi3

That day I noticed an isolated speck of nebulosity in survey image ( Digitized Sky Survey) and checked other surveys too we found that the signal is true so we proceeded on to checking whether it is known or unknown so we checked on the Database and found that it is still unknown!! Later we also checked in the hydrogen alpha survey that this object is emitting strong Ha signal, we could not digest that how can such bright object be ignored by other researchers so we thought that its likely a bright HII region which is of not much scientific value so it might have got ignored, we asked the expert comments from Marcel, Xavier and Dana and I think none of our views were very much cleared on this object as it had very unusual shape/data like a Hindu tilak, Hence we named that after it.


PanSTARRS DR 1 survey shows the structure beautifully, you might also notice a small White Dwarf below we thought this might be related to this nebula in some way? The size of MoMi-3 is quite small only 1 x 0.4 arc min although there have been small objects but due to its shape it seems to be unique to us. As I mentioned above MoMi-3 was also visible in hydrogen alpha survey here is it.

MoMi 3 visible in Ha Survey

After looking into different surveys we decided to submit this candidate to pascal and after few days we got a reply from Lionel Mulato who managed to obtain spectrum of Momi-3. Lionel gave us a big surprise by telling that : [N II] >> H-alpha, intensity of H-alpha unmeasurable and blended with [N II]6548. [N II]6584/Ha ratio higher than 5 ; [O III] in blue and no [S II] nor H-bêta.

MoMi-3 Spectrum Obtained By Lionel Mulato

Meaning the object was emitting strong NII lines and slight OIII signal which tells that this could be a Planetary Nebula, Lionel also added that MoMi-3 is a Nitrogen rich amorphous and compact object. It may be a reddened Type I PN (like RCW69) Now the object has been waiting for final validation from

Dr. Quentin Andrew Parker.

When we got this news we were very happy and shared with Xavier, Marcel & Dana we were extremely surprised what this object has turned out to be. Now we decided to photograph this object we approached Peter Goodhew he is expert in photographing small objects with his dual rig that is hosted in Spain.

Peter Goodhew's Dual Imaging setup in Spain : APM 152 and QSI

Peter quickly shot Ha-OIIILRGB with his remotely hosted equipment and sent us the fits files I quickly took a look and it was nicely resolved so I proceeded in processing it, I used Pixinsight and Photoshop to process it.

Combined images in PS ha-OIII and RGB, sharpening was done in Pixinsight, since the object was small there was nothing much to bring out so I did not apply any processing after combination and sharpening and colors adjustments. We also decided that adding a great IC 2177 as background would be good option so we approached Ciel austral Guys, I took their permission to use it as my background image for our new discovery. Thank you Philippe BERNHARD

They took around 370hrs of exposer to bring out enormous amount of details in the IC 2177

Background image by Ciel Austral team also displaying MoMi3

We also made a 1 min video on our discovery :) hope you like it :)) we would publish more such discoveries in future if you like my work you can connect me on instagram, @mr_deepsky I regularly post astrophotography content. MoMi-3 PN-G 225.5-01.9

Object co-ordinates : 07:07:51.23 -12:07:50.92

size : 1 x 0.4 arc min

Image captured on remote dual rig at Spain

Scopes: APM TMB LZOS 152 Refractors

Cameras: QSI6120wsg8

Mount: 10Micron GM2000 HPS _ By Peter Goodhew Image Processing : Utkarsh Mishra

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