by Ann » Tue Oct 09, 2018 11:17 pm
Now that I've looked at the APOD on my big computer screen at home, I like the picture a lot better than when I looked at it on my much smaller computer screen at work. Many of the details are stunning. Note, for example, how halfway between the outer left arm and the center there is a star forming site in an inner arm that is virtually "smoking stars", like a chimney is "smoking smoke", or like a popcorn saucepan is popping popcorns.
One thing that makes me wonder is the apparent lack of red giant stars. Yes, there are a few "ordinary-looking" red giants to be seen, but very few of them. Compare today's APOD with this
1.26 MB Hubble picture of NGC 4214. (Or check out
this page.)The pictures of NGC 1672 and NGC 4214 are not comparable, since different filters were used for them, but please note, nevertheless, how many red giants there are among the blue stars in the Hubble picture of NGC 4214.
In NGC 1672, by contrast, there are
a few normal-looking red giants and a number of too-bright ones. There are two overly bright ones near 2 o'clock, one of them located just below a small site of star formation. These two apparently stellar objects are small, round, very orange and very bright in the middle, and they don't look much (or at all) like the obvious orange-colored background galaxies that can be seen right through the disk of NGC 1672. But even though these apparently stellar objects are small, they are a lot bigger and brighter than virtually every blue star in NGC 1672. I guess they might be very distant elliptical galaxies, particularly since there are two smaller orange objects to the right of one of them. But there are other overly bright stellar-looking orange objects in the picture that don't look much like background galaxies, and there are, in my opinion, too few normal-looking red giants among the blue stars.
Or maybe the confusion arises from a lack of color saturation, so that the red stars don't stand out too clearly from the blue ones.
Ann
Now that I've looked at the APOD on my big computer screen at home, I like the picture a lot better than when I looked at it on my much smaller computer screen at work. Many of the details are stunning. Note, for example, how halfway between the outer left arm and the center there is a star forming site in an inner arm that is virtually "smoking stars", like a chimney is "smoking smoke", or like a popcorn saucepan is popping popcorns.
One thing that makes me wonder is the apparent lack of red giant stars. Yes, there are a few "ordinary-looking" red giants to be seen, but very few of them. Compare today's APOD with this [b][size=120][color=#0000FF]1.26 MB[/color][/size][/b] [url=http://imgsrc.hubblesite.org/hvi/uploads/image_file/image_attachment/21647/large_web.jpg]Hubble picture of NGC 4214[/url]. (Or check out [url=https://www.spacetelescope.org/news/heic1109/]this page[/url].)The pictures of NGC 1672 and NGC 4214 are not comparable, since different filters were used for them, but please note, nevertheless, how many red giants there are among the blue stars in the Hubble picture of NGC 4214.
In NGC 1672, by contrast, there are [i]a few[/i] normal-looking red giants and a number of too-bright ones. There are two overly bright ones near 2 o'clock, one of them located just below a small site of star formation. These two apparently stellar objects are small, round, very orange and very bright in the middle, and they don't look much (or at all) like the obvious orange-colored background galaxies that can be seen right through the disk of NGC 1672. But even though these apparently stellar objects are small, they are a lot bigger and brighter than virtually every blue star in NGC 1672. I guess they might be very distant elliptical galaxies, particularly since there are two smaller orange objects to the right of one of them. But there are other overly bright stellar-looking orange objects in the picture that don't look much like background galaxies, and there are, in my opinion, too few normal-looking red giants among the blue stars.
Or maybe the confusion arises from a lack of color saturation, so that the red stars don't stand out too clearly from the blue ones.
Ann