Some PNe candidates confirmation

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Some PNe candidates confirmation

Postby Lionel Mulato » Fri Jun 07, 2019 10:13 am

Hello all,

Here are some spectra taken from my backyard observatory.
Among the 6 Planetary Nebula candidates I've taken :
- 4 are certainly True PNe,
- 1 might be an HII region or ISM ionized nebula,
- 1 is probably a red giant star that mimics the middle infrared features of PNe,

****
1) Kn 121 (20 42 01.9 +13 51 15) discovered by M. Kronberger, status "Probable PN" in HASH database.

This is an extremely faint and large PN candidate.
Here is an image from the KNPO taken with a 4m telescope.

Image

The [O III] doublet appeared very faintly on the raw 2D sub spectrum (1200 s). I was about to give up the acquisitions, because I wasn't sure that the signal was real or not.
The processed spectrum is very noisy, but the doublet appears clearly with the right relative intensity. I didn't detect any Halpha line.
I think Kn 121 is a True PN.

Image
Image

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2) Kn 68 (07:22:03.15 27:13:33.5) discovered by M. Kronberger, status "Likely" in HASH database.

Here is an "easy" bright one.
According to its shape and its spectrum, Kn 68 is certainly a True PN.

PanSTARRS image :

Image

Image


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3) Alv 5 (17:12:41.70 +01:55:33.1) discovered by F. Alves, status "Probable PN" in HASH database.

Here is another tough faint one.
Image from KNPO :

Image

You can see the faint [O III] doublet on the 2d spectrum and an extremely faint Ha line. Alv 5 is certainly a True PN.

Image
Image

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4) PM 1-320 (20 10 32.30 +44 11 48.5), discovered by A. Preite-Martinez in the 80s thanks to IRAS survey, status "Probable PN" in HASH database.

This is a very bright candidate, strangely it seems there's no spectrum yet available for this object.
Image from PanSTARRS and DSS2 :

Image

1D Spectrum just showing [O III] and Halpha lines:

Image

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5) PaTe 1 (19:43:29.40 +40:20:05.0), discovered by D. Patchik and Teutsch, status "Probable PN" in HASH database.

This nebula is relatively bright.
DSS2 image :

Image

There is no [O III] emission lines, only Halpha, Hbeta and [S II]. It might be an HII region.

Image

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6) Mul-IR-67 (18:20:30.30 +44:49:12.0).

This object is one of my IR PN candidates selected on middle infrared criteria. The criteria are defined in an article I wrote with Agnes Acker in 2015. Among these MIR candidates there could be a lot of PN mimics (proto PNe, dying stars, or young stellar objects...).

WISE Allcolor image :

Image

Here is the spectrum.
Image

Unfortunately the object isn’t a PN despite its MIR colors match very well PNe' ones.
But it's still interesting to guess what this object is !

It seems to be a cool star with a very bright IR counterpart.
There is some broad absorption bands (5500 – 5600 A ; 6100 – 6300 A ; 6600 – 6800 A ; 7100 – 7200 A). The line 6240 A seems to be real (not an artefact) but I can't identify it.

The star doesn't seem to be variable. Several optical surveys give similar magnitudes for this star (GAIA, GSC2.3, USNO). In Middle IR too, WISE and IRAS surveys give almost the same magnitude. So this star is certainly not on the Asymptotic Giant Branch.

According to its optical and IR signatures, I think the star has entered in Red Giant Branch. Those stars are often weakly variable and they are surrounded by a dust shell emitting strongly in IR.
We have to wait few more millions years until this star turns into a PN ;)
Lionel Mulato
 
Posts: 13
Joined: Sat Oct 27, 2018 12:49 pm

Re: Some PNe candidates confirmation

Postby Lionel Mulato » Fri Jul 05, 2019 11:21 pm

Re,

Pour ceux qui préfèrent le français : voir les résultats ici.

Voici une autre NP classée possible (P) dans la base HASH : IPHASX J194533.8+210751.

Image SDSS9 + IPHAS Ha :

Image

Les raies [O III], Halpha, [N II] sont clairement détectées. Le doublet du [S II] semble aussi présent mais très faible. Le spectre semble indiquer que l'objet est bien une NP.

Image
Lionel Mulato
 
Posts: 13
Joined: Sat Oct 27, 2018 12:49 pm


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