Star CarbonWD

• by bluemagi

  Found this on my journeys on the SDSS. Its OBJ.ID 1237651272967258267 RA:147.906657451 DEC: 62:730199630. The spectrum looks like Dwarf so why is it listed as a carbonWD? Carbon spectrums are totally different. Thanks Bluemagi.

  Posted October 7, 2016 1:53 AM

• by Budgieye moderator

  Maybe it means a white dwarf spectrum, with a small amount of carbon? The carbon might come from the star cooling, or it may be a image contamination from the yellow star nearby.

  The survey is looking for cool white dwarfs, "cool" as in temperature. So they are looking at those inverse slope spectra. The results are to estimate the age of the Milky Way Galaxy. https://www.sdss3.org/surveys/segue2.php

  The spectroscopic selection also includes smaller categories of rare
  but interesting objects. These include cool white dwarfs, which can be
  used to date the age of the Galactic disk, and high proper motion
  targets from the SUPERBLINK catalog, which have uncovered some of the
  most extreme M subdwarfs known and aided in the calibration of their
  metallicity scale using common proper motion pairs.

  http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237651272967258267

  

  http://skyserver.sdss.org/dr12/SkyserverWS/ImgCutout/getjpeg?TaskName=Skyserver.Explore.Image&ra=147.906657450855&dec=62.7301996298012&scale=0.2&width=200&height=200&opt=G

  

  http://skyserver.sdss.org/dr12/en/get/SpecById.ashx?id=2705696144364693504

  ---

  Here is an interesting link, to the kind of low temperature white dwarf that they are looking for.

  Forum OOTD: Saturday August 7 2010 White dwarf stars are hot, aren't they? http://www.galaxyzooforum.org/index.php?topic=278111.msg484589#msg484589 an ultra cool white dwarf

  It is an ultra-cool white dwarf. So I attach the appropriate smiley
  8) I had thought that it took billions of years for a white dwarf to
  cool off, longer than the current age of the universe. The paper
  acknowledges that problem. It is probably a helium core white dwarf,
  which logically should be the coolest sort, with very little hydrogen
  having survived the explosion. It must have been formed when the
  universe was very young. Still, a pretty picture and a lovely
  spectrum.

  

  http://skyservice.pha.jhu.edu/DR7/ImgCutout/getjpeg.aspx?ra=253.50518908&dec=62.89860344&scale=0.2&width=200&height=200&opt=G

  

  http://cas.sdss.org/dr7/en/get/specById.asp?id=98456813309001728

  http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587725490523340876

  Posted October 7, 2016 6:10 AM

• by bluemagi

  Thanks. Its interesting to learn new things.

  Posted October 7, 2016 6:43 AM