| Topic: |
Science > Physics |
| User: |
"Starlight-Starbright" |
| Date: |
16 Jan 2005 12:04:55 PM |
| Object: |
Color of milky way's starlight |
If the center of the milky way galaxy (the 'core') has more population
II stars that are old and red, then that should make the galaxy appear
more reddish when seen from somewhere far out like the Large or Small
Magellanic Cloud.
We aren't fortunate enough to be able to see it from there, but can
CCDs record a redder tinge to the Milky way's diffuse starshine in the
sky at night? Not sure if this been discussed before...?
cheres (me dears)!!!
S-S
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| User: "Steve Willner" |
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| Title: Re: Color of milky way's starlight |
19 Jan 2005 03:56:18 PM |
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In article <1105895967.377746.76200@c13g2000cwb.googlegroups.com>,
"Starlight-Starbright" <starlight-starbright@rock.com> writes:
If the center of the milky way galaxy (the 'core') has more population
II stars that are old and red, then that should make the galaxy appear
more reddish when seen from somewhere far out like the Large or Small
Magellanic Cloud.
You can get an idea from looking at spiral galaxies such as M31 or
M81 (or indeed thousands of others). In visible light, the bulge is
indeed typically redder than the disk, though not by a huge amount.
The Milky Way's "diffuse starshine" as seen from Earth is in fact
mostly light from individual stars in the magnitude range 8 to 10
(IIRC). These are mostly disk stars and on average a bit bluer than
bulge stars, but they are also reddened by interstellar dust. I
don't know what the average visible-light color turns out to be. If
you extend your wavelength coverage to the infrared, you begin to
penetrate the dust to great distances, the average reddening is high,
and the average color is quite red. See the 2MASS or COBE
depictions, for example.
--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)
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| User: "G=EMC^2 Glazier" |
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| Title: Re: Color of milky way's starlight |
19 Jan 2005 04:21:31 PM |
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Seems the disk of a spiral galaxy could have a mix as the colors
red(turning away) and blue turning towards our line of view.(oops just
remembered) we are also turning I know this was tricky as the Milky
Way(us) and the Andronema galaxy. can have blue on one side and red on
the other.(go figure) Bert.
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| User: "John Popelish" |
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| Title: Re: Color of milky way's starlight |
16 Jan 2005 12:24:16 PM |
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Starlight-Starbright wrote:
If the center of the milky way galaxy (the 'core') has more population
II stars that are old and red, then that should make the galaxy appear
more reddish when seen from somewhere far out like the Large or Small
Magellanic Cloud.
We aren't fortunate enough to be able to see it from there, but can
CCDs record a redder tinge to the Milky way's diffuse starshine in the
sky at night? Not sure if this been discussed before...?
cheres (me dears)!!!
Here is a link to views of the Milky Way in many different wavelength
ranges. The first one is a composite of color photographs,
approximately the colors you would see if your eyes were more
sensitive to dim light.
http://astro.wsu.edu/worthey/astro/html/lec-milky-way.html
--
John Popelish
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| User: "" |
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| Title: Re: Color of milky way's starlight |
16 Jan 2005 06:03:42 PM |
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Starlight-Starbright wrote:
If the center of the milky way galaxy (the 'core') has more
population
II stars that are old and red, then that should make the galaxy
appear
more reddish when seen from somewhere far out like the Large or Small
Magellanic Cloud.
We aren't fortunate enough to be able to see it from there, but can
CCDs record a redder tinge to the Milky way's diffuse starshine in
the
sky at night? Not sure if this been discussed before...?
cheres (me dears)!!!
S-S
Inverse square law: even if there are more "red' stars in one
direction, the distance factor with the younger "bluer" stars being
closer around here may cancel??
Jim G
c'=c+v
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| User: "Greg Crinklaw" |
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| Title: Re: Color of milky way's starlight |
16 Jan 2005 06:26:45 PM |
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wrote:
Starlight-Starbright wrote:
If the center of the milky way galaxy (the 'core') has more
population
II stars that are old and red, then that should make the galaxy
appear
more reddish when seen from somewhere far out like the Large or Small
Magellanic Cloud.
We aren't fortunate enough to be able to see it from there, but can
CCDs record a redder tinge to the Milky way's diffuse starshine in
the
sky at night? Not sure if this been discussed before...?
cheres (me dears)!!!
S-S
Inverse square law: even if there are more "red' stars in one
direction, the distance factor with the younger "bluer" stars being
closer around here may cancel??
Uh uh. What happens in practice is that those very few, but *very*
luminous blue stars tend to steal the show.
Greg
--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)
SkyTools Software for the Observer:
http://www.skyhound.com/cs.html
Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html
To reply have a physician remove your spleen
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