Disk Detective Talk

Lack of easily distinguishable nonsaturated stars.

  • Artman40 by Artman40

    I have noticed that most of the stars that can be easily identified in SED light curve are already saturated with diffraction spikes visible. Is it because

    1. Most non-saturated stars have a different SED light curve?
    2. Non-saturated stars do not have bright enough circumstellar disks or ejected material to be detected in WISE?
    3. Non-saturated stars were not selected from the list of WISE objects to be displayed here?

    Although I have noticed some of these non-saturated stars (as few of them as there are) still have SED curves that indicate their nature.

    Can someone provide more information?


  • abans by abans scientist, moderator

    There are indeed stars with disks that are non-saturated/ give no noticeable diffraction spikes, in principle they should have similar SEDs to the bright stars with disks too.... they'd just be further away from us than the bright sources. In fact, these are the guys we are really looking for, because a lot of the really bright sources may already be known disks (though we like finding those too in order to verify that our project works). Some of the non-saturated objects that look like stars and have really different SEDs may actually be unknown galaxies/agn.

    We didn't really filter out the faint objects ( we mostly want to get rid of the extremely bright stuff because like I said that is the stuff that is well studied already), but there is a limit to the magnitude/brightness of an object WISE can detect, so alas, there are still going to be disks out there that we can't find.

    Hope that helped.


  • lrebull by lrebull scientist, translator, admin

    Hm, I'm not sure what you're asking in some of these questions. We picked objects based on their WISE properties, and so they shouldn't be saturated in the WISE bands. But, they may be saturated in DSS, SDSS, or 2MASS. Most of the ones I have seen are not saturated. The points that go into the SED are (I think) just 2MASS+WISE, and if the SED includes those 2MASS bands, then the stars are not saturated in those bands (we shouldn't be grabbing points that are truly saturated). Now, if you meant that the object is just very bright (not the technical definition of saturation, but a more colloquial meaning of "just really freaking bright"), then it could still be really bright in more than one bands. Stars at any distance could have disks; whether or not they are saturated, or bright, or close to us, doesn't have any influence on whether or not there is a disk around it. I'm not sure how you could tell it was saturated from the SED, except if the points were missing. A source that is very bright in all of the available bands will most likely have a blackbody like SED until WISE bands; if it's still very bright at the WISE bands, then the SED most likely rises like crazy, e.g., it has a big whomping disk. Hope that helps.