Now with more amateur astronomers being equipped with larger instruments, along with the increasing amount of High-resolution survey data being released to the public online (SDSS, Pan-STARRS; DECaPS, etc), amateurs are playing an important role in the total number of discovered Planetary Nebulae!
Below are just some of the numerous Planetary Nebulae that were discovered in late 2017 and early 2018 by amateur astronomers. These do not include the discoveries made by the Deep Sky Hunters group (they deserve a blog post of their own! ) Anyways, this blog post is already longer than usual! 🙂
As can be seen when looking at these discoveries, it’s obvious that there are still many beautiful Planetary Nebulae still waiting to be discovered!
CaVa 1 – Vast and complex circular Planetary Nebula
This is a beautiful circular Planetary Nebula discovered by Jean-Paul Cales et Michael Vanhuysse (France) in an Halpha image they took via their observatory in Nerpio (Spain). The nebula has a large apparent size, almost 7′ in diameter! Its morphology is almost completely circular, displaying internal heterogeneities. The nebula is also very obvious in IPHAS survey data, and also faintly detectable in images from the Digitalized Sky Survey and Pan-STARRS1. Pascal Le Dû (France) confirmed the object to be a true Planetary Nebula via his own spectroscopic observations.
Image extract of CaVa 1 as imaged by Stephane Zoll (France). The image is a combination of an Halpha and OIII exposure, colour-coded red and blue respectively. Notice how the nebula almost appears as a complete (heterogeneous) disk. (c) Stephane Zoll.
IPHAS Halpha Image extract partially showing CaVa 1. In these images too the nebula is very circular, displaying an inner “bar” structure dividing the nebula in two nearly-equal halves! Image credit: IPHAS Halpha
DSS Image extract showing *very faintly* CaVa 1. In these images only the most enhaced parts of this PN appear. One can partially see the nebula as a very faint arc covering the lower and lower-right part of this image.
Su 1 – Bipolar Planetary Nebula candidate with no optical counterpart
Guyou Sun (China) discovered this very strange nebula in images from the WISE satellite, where the object displayed a Mid-Infrared signal typical of a Planetary Nebula. Atypical of Planetary Nebulae however, Su 1 appears best in the Near-Infrared, where PNe usually appear the faintest! Furthermore, the nebula doesn’t seem to appear in optical images at all. The nebula displays a remarkable bipolar nature, especially as seen in Pan-STARRS1 images. Su 1 is also faintly apparent in Infrared images from the Digitalized Sky Survey.
Pan-STARRS1 image extract showing Su 1. Notice the object’s very obvious bipolar nature, stemming from a bright Near-Infrared central object. The object lacks an optical counterpart in Pan-STARRS1, which is very atypical of Planetary Nebulae! Image credit: Pan-STARRS1 Science Consortium
Su 1 as seen in a Near-Infrared DSS frame. The lines mark the center of the object, and is quasi-perpendicular to the orientation of the bipolar nebula (faintly visible). Image credit: DSS Plate Finder.
Tan 2 – Possible condensed elliptical Planetary Nebula
This is a small Planetary Nebula candidate discovered by Hanie Tan (China) using survey images from the WISE satellite, the Digitalized Sky Survey (DSS), SuperCosmos Halpha Sky Survey (SHS) and Pan-STARRS1. The object was first flagged as an emission-star but Pan-STARR1 clearly indicated the object to be a nebula, with the morphology and colours typical of a Planetary Nebula! The SHS images also seem to faintly reveal the object’s non-stellar nature.
Pan-STARRS1 image extract showing Tan 2 as an obvious compact elliptical nebula. It’s green colorimetry in these images is typical of Planetary Nebulae. Image credit: Pan-STARRS1 Science Consortium.
SHS Image comparison showing Tan 2. Notice the object’s non-stellar nature, as well as its very strong Halpha signal, typical of Planetary Nebulae. Image credit: SuperCosmos Halpha Sky Survey.
St 4 – Possible quasi-stellar Planetary Nebula
This is a small compact Planetary Nebula candidate discovered by Xavier Strottner (France) online using the Digitalized Sky Survey Plates (DSS). In these images, the object appears best in the optical plates, rather than in the Infrared DSS images (which is a good sign of a Planetary Nebula!). Despite the object apearing alot more disk-like (with a central condensation) in Pan-STARRS1, the object has the colorimetry more typical of a galaxy in those images.
St 4 is the small, round and diffuse object located at the center of this coloured DSS2 image extract. Its morphology is typical of compact Planetary Nebulae. Image credit: DSS2 Aladin Lite.
St 3 as seen in a Pan-STARRS1 image extract. These images seem to reveal St 3 to have a round morphology with a central condensation. However, Pan-STARRS1 data is also in favour of this being a small unresolved spiral galaxy too. Image credit: Pan-STARRS1 Science Consortium.
St 9 – Possible elongated Planetary Nebula
This is another PN candidate discovered by Xavier Strottner in images from the Digitalized Sky Survey (DSS). Unlike St 3, St 9 is a rather obvious and diffuse nebula (as can be seen in the image below). It appears best in bluer images, such as in the DSS blue plates. The object is also obvious in the Mid-Infrared, displaying a typical Mid-IR signature of a PN!
St 9 as seen in a coloured image from the Digitalized Sky Survey (DSS). Image credit: DSS2 Aladin lite.
Mo 7 – Possible obscured compact Planetary Nebula
Sankalp Mohan (India) discovered this small Planetary Nebula candidate in WISE satellite data, where it diplayed the typical Mid-Infrared signature of a Planetary Nebula. It was initially rejected from being kept as a PN candidate, as it did not display any signs of nebulosity (more observations were needed). It wasn’t until the release of DECaPS in 2018 that Mo 7 was a confirmed to be a nebulous, and hence a Planetary Nebula candidate!
DECaPS coloured image extract showing Mo 7 as a small round nebula. These were the images that confirmed the objects nebulous nature. Image credit: DECaPS Aladin Lite.
AllWISE Image extract showing Mo 7 (centered). The “red” colour is due to the colour coding, with the red band corresponding to the WISE W4 filter. PNe usually respond best in these images, hence the colour! Image credit: AllWISE Aladin Lite.
LDû 36 – Possible Round and faint Planetary Nebula
This nice Planetary Nebula candidate was discovered by Pascal Le Dû (France) in images from the SHS Halpha survey. In the visible wavelength, the nebula only seems to appear in these images, even in DECaPS and Pan-STARRS1! The nebula however emits significantly in the Mid-IR, with a signature in WISE images typical similar to many PNe. Its nebulosity also seems to be visible in Mid-IR images.
SHS Halpha Image extract showing LDû 36. Notice its round morphology, similar to many Planetary Nebulae. This is the only current optical image available for this object, so far! Image credit: SuperCosmos Halpha Sky Survey.
Spitzer image extract showing a faint nebulosity and poorly defined, likely corresponding to LDû 36. Its colour-coded green colorimetry in these images is very common in the case of Planetary Nebulae. Image credit: Spitzer Aladin Lite.
Pre 43 – Possible blue Planetary Nebula with a complex morphology
I first noticed this possible Planetary Nebula in images from the WISE and DECaPS surveys online, where it appears as a rather heterogeneous, clumpy and elongated blue nebula. In images from the Digitalized Sky Survey (DSS) the nebula mixes rather well with the surrounding nebulosity, but DECaPS, Narrow-band (OIII and Halpha) and WISE Mid-Infrared images clearly indicate it to be seperate and an independent nebula!
Pre 43 as seen in a OIII+NII image extact taken by Bert Van Donkelaar. The nebula appears as a tiny blue patch of nebulosity at the center of this image. The image indicates that Pre 43 emits strongly in the OIII band, typical of PNe. (c) Bert Van Donkelaar.
DECaPS Image extract showing Pre 43. In these images it appears as a complex, heterogeneous, clumpy and elongated blue nebula. The brightest part of this nebula is 0.5′ x 0.7′ in size. This is surrounded by a faint, vague and blue halo measuring perhaps 2′ x 1′ in size. Image credit: DECaPS Aladin Lite.
Image comparison between a SHS Short Red and Halpha frame showing Pre 43. Notice how the nebula only seems to appear in Halpha. This is typical of Planetary Nebulae as they most often have hydrogen emissions. Image credit: SuperCosmos Halpha Sky Survey.
DeGaPe 51 – Possible vast circular Planetary Nebula
This is an apparently round nebula that appears best in OIII narrow band images, discovered by the APO team (Thierry Demange, Richard Galli and Thomas Petit) in combined narrow band images. The team photographs the sky regularly using OIII, Halpha and SII filters (then combining them them to create a coloured “SHO” image), to obtain images like the one below! Except for in OIII, DeGaPe 51 is optically very faint, being undetectable in most optical surveys, including Pan-STARRS1!
Discovery SHO image extract showing DeGaPe 51. Notice its rather round morhpology as seen in these images, appearing mainly in the OIII band (colour coded blue). (c) APO Team.
SHS Halpha Image extract of DeGaPe 51. Notice how the object is poorly detectable in this image. Other than these survey images, the nebula seems to be absent in other optical survey, such as the Digitalized Sky Survey and even Pan-STARRS1! Image credit: SuperCosmos Halpha Sky Survey
DeGaPe 54 – Possible Stellar Planetary Nebula
This is yet another Planetary Nebula candidate discovered by the APO team in their combined SHO narrow-band images. This object is very stellar as seen in survey data, not even DECaPS indicate any signs of a nebulous nature! Furthermore, the object displays an Infrared excess atypical of most PNe! Only narrow band images seem to indicate this object to have PN-like charactersistics.
Discovery SHO image extract showing DeGaPe 54, located at the center of this image. Despite its stellar morphology, its flashy green colour in this image clearly distinguishes it from the rest of the background stars! (c) APO Team
DeGaPe 54 as seen in the combined colour DECaPS images. Unlike the SHO image, the object is impossible to distinguish from the surrounding stars! This image also suggests the object could be slightly obscured by the nebulosity in this region. Image credit: DECaPS Aladin Lite.
DeGaPe Object 3 – Possible diffuse Planetary Nebula?
As of April 12th, 2018 this is the most recent discovery made by the APO team. It’s a rather faint and diffuse object that could be a Planetary Nebula. However, based on its designation, this status is still pending. The nebula is optically faint (not even detectable in DECaPS images!), essentially emitting in OIII. In the Mid-IR however the nebula is obvious, with a typical PN-like signature in WISE!
Discovery SHO image extract of DeGaPe Object 3. Notice its rather diffuse morhpology as seen in these images, appearing mainly in the OIII band (colour coded blue). (c) APO Team.
Ra 66 – Strongly obscured compact Planetary Nebula candidate
This Planetary Nebula candidate was discovered by Thierry Raffaeili (France) using the available SDSS images online, via Skymap.org. The nebula is round and apparently compact. It is optically faint, but it has a much brighter Infrared counterpart (with a Mid-Infrared signal typical of most Planetary Nebulae). Its faintness in optical images is most likely due to this object being strongly obscured behind thick dust of a star forming region.
Combined colour SDSS image extract showing Ra 66 as a faint round nebulosity, laying next to a relatively bright star. The colorimetry of the nebula in these images is not typical of a Planetary Nebula, but this effect might just be due to this object being strongly obscured behind thick dust of a star forming region. Image credit: SDSS Aladin Lite.
Combined Mid-Infrared AllWISE image extract showing Ra 66. Its colorimetry in these images is the typical signature of a Planetary nebula (similar to Mo 7, further above). Image credit: AllWISE Aladin Lite