ARG0003cnb GREEN STAR? & GALAXY
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by 1001G
SDSS J231814.95+063512.1 GREEN STAR? THE RIGHT OF GALAXY? SDSS J231816.26+063508.8 NGC 7591.
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by ivywong scientist, admin
Hi @1001G.
The observed green colour usually comes from the Oxygen emission line. These could be evolved massive stars such as the Wolf-Rayet class of stars.
Does this help?
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by JeanTate in response to 1001G's comment.
Hi 1001G.
SDSS J231814.95+063512.1 GREEN STAR?
It's very likely an artifact, the result of a cosmic ray hitting a pixel or two in the r-band part of the SDSS camera (and not being removed by the photometric pipeline).
Why do I say that?
Because:
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in both DR7 and DR10, in the Explore view, it says "WARNING: This object's photometry may be unreliable. See the photometric flags below." and "TOO_FEW_GOOD_DETECTIONS PSF_FLUX_INTERP DEBLEND_NOPEAK DEBLENDED_AT_EDGE INTERP_CENTER BINNED1 DEBLENDED_AS_PSF INTERP COSMIC_RAY NOPETRO CHILD" Those 'flags' basically tell you that this 'object' may not actually be something in the sky
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particularly in DR7, the stated magnitudes in all bands but r are really no different from 'the sky' (and the errors are huge); this is common for cosmic ray artifacts
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as far as I know, even planetary nebulae and HII regions do not have colors* like those of this 'star', for any reasonable redshift
*astronomer-speak colors; i.e. things like (u-g), or (r-i).
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