by Ann » Sat Oct 26, 2024 6:18 am
Because the APOD is so large, more than 800 KB, I won't copy it. Instead, let's look at a few other pictures of the illuminating star Gamma Cas, and the "ghosts" named IC 59 and IC 63.Rogelio Bernal Andreo's beautiful portrait of Cassiopeia is a good place to start!
A closer look at Rogelio Bernal Andreo's picture reveals a truly huge and flattened dark "smoke circle" surrounding surrounding Gamma Cas. Inside that dark smoke circle is a smaller red semicircle, and IC 63 and IC 59 are the two bright "outcrops" of this semicircle.
Here is a closer closeup of IC 59 and IC 63 along with their source of illumination and ionization, Gamma Cas:
The huge dark dust circle surrounding Gamma Cas could possibly have been created by Gamma Cas itself,
or so I think. (Warning! Amateur guess!) Please note, however, that Wikipedia calls it an eruptive variable star:
Wikipedia wrote:
Gamma Cassiopeiae is
an eruptive variable star, whose apparent magnitude changes irregularly from 1.6 at its brightest to 3.0 at its dimmest. It is the prototype of the class of Gamma Cassiopeiae variable stars. In the late 1930s it underwent what is described as
a shell episode and the brightness increased to above magnitude 2.0, then dropped rapidly to 3.4. It has since been gradually brightening back to around 2.2.
Gamma Cassiopeiae is a rapidly spinning star with a projected rotational velocity of 472 km s−1, giving it a pronounced equatorial bulge. When combined with the star's high luminosity, the result is the ejection of matter that forms a hot circumstellar disk of gas. The emissions and brightness variations are apparently caused by this "decretion disk"
So Gamma Cas
is ejecting matter that forms a hot circumstellar disk around the star. Isn't it reasonable that IC 63 and IC 59 originated as particularly dense "clumps" that were ejected by Gamma Cas? And now these clumps are located a few light-years away from Gamma Cas, and they are ionized and illuminated by the hot bright star. IC 63 is a little bit closer to Gamma Cas, so it is ionized to glow red, and IC 59 is a little further away, so it is mostly illuminated to reflect a soft shade of blue.
I can't help thinking that Gamma Cas is a very little brother or sister of the mighty and extremely hot Wolf-Rayet stars, which eject huge amounts of matter:
According to Wikipedia, Gamma Cas is 8 million years old. It has 17 times the Sun's mass and is radiating as much energy as 34,000 Suns. Its outer atmosphere has a temperature of 25,000 K, compared with 5778 K for the Sun. And it
is ejecting matter. It seems certain (to me at least) that the red semicircle surrounding Gamma Cas could be matter ejected and then ionized by Gamma Cas. The question is if the huge dark circle surrounding it could also have been created by Gamma Cas. Is the star old enough to have flung matter so very far away from it?
Anyway. Because I've been talking about Gamma Cas the whole time now, I can't help thinking of Mama Cass from the Mamas and the Papas. So let's hear it from the Mamas and the Papas!
Click to play embedded YouTube video.
Ann
Because the APOD is so large, more than 800 KB, I won't copy it. Instead, let's look at a few other pictures of the illuminating star Gamma Cas, and the "ghosts" named IC 59 and IC 63.Rogelio Bernal Andreo's beautiful portrait of Cassiopeia is a good place to start! :D
[img3="The W in Cassiopeia.
Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)"]https://apod.nasa.gov/apod/image/1603/RBA_Cassiopeia_1024_Labeled.jpg[/img3]
A closer look at Rogelio Bernal Andreo's picture reveals a truly huge and flattened dark "smoke circle" surrounding surrounding Gamma Cas. Inside that dark smoke circle is a smaller red semicircle, and IC 63 and IC 59 are the two bright "outcrops" of this semicircle.
[attachment=0]APOD 18 March 2016 detail.png[/attachment]
Here is a closer closeup of IC 59 and IC 63 along with their source of illumination and ionization, Gamma Cas:
[img3="Gamma Cas with IC 59, at 6 o'clock, and IC 63, at 4 o'clock. Credit: Jonathan Talbot."]https://www.starscapeimaging.com/Gamma%20Cass/files/stacks-image-ae34a5a-1198x800.jpg[/img3]
The huge dark dust circle surrounding Gamma Cas could possibly have been created by Gamma Cas itself, [b][i]or so I think[/i][/b]. (Warning! Amateur guess!) Please note, however, that Wikipedia calls it an eruptive variable star:
[quote][url=https://en.wikipedia.org/wiki/Gamma_Cassiopeiae#Physical_properties]Wikipedia[/url] wrote:
Gamma Cassiopeiae is [b][size=110][color=#0040FF]an eruptive variable star[/color][/size][/b], whose apparent magnitude changes irregularly from 1.6 at its brightest to 3.0 at its dimmest. It is the prototype of the class of Gamma Cassiopeiae variable stars. In the late 1930s it underwent what is described as [b][size=110][color=#0040FF]a shell episode[/color][/size][/b] and the brightness increased to above magnitude 2.0, then dropped rapidly to 3.4. It has since been gradually brightening back to around 2.2.[/quote]
[quote][b][size=110][color=#0040FF]Gamma Cassiopeiae is a rapidly spinning star[/color][/size][/b] with a projected rotational velocity of 472 km s−1, giving it a pronounced equatorial bulge. When combined with the star's high luminosity, the [b][size=110][color=#0040FF]result is the ejection of matter that forms a hot circumstellar disk of gas[/color][/size][/b]. The emissions and brightness variations are apparently caused by this "decretion disk"[/quote]
So Gamma Cas [b][i]is[/i][/b] ejecting matter that forms a hot circumstellar disk around the star. Isn't it reasonable that IC 63 and IC 59 originated as particularly dense "clumps" that were ejected by Gamma Cas? And now these clumps are located a few light-years away from Gamma Cas, and they are ionized and illuminated by the hot bright star. IC 63 is a little bit closer to Gamma Cas, so it is ionized to glow red, and IC 59 is a little further away, so it is mostly illuminated to reflect a soft shade of blue.
I can't help thinking that Gamma Cas is a very little brother or sister of the mighty and extremely hot Wolf-Rayet stars, which eject huge amounts of matter:
[img3="Wolf-Rayet star WR 31a is surrounded by a bubble of its own making. Credit: ESA/Hubble & NASA. Acknowledgement: Judy Schmidt"]https://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/WR_31a.jpg/1024px-WR_31a.jpg[/img3]
According to Wikipedia, Gamma Cas is 8 million years old. It has 17 times the Sun's mass and is radiating as much energy as 34,000 Suns. Its outer atmosphere has a temperature of 25,000 K, compared with 5778 K for the Sun. And it [b][i]is[/i][/b] ejecting matter. It seems certain (to me at least) that the red semicircle surrounding Gamma Cas could be matter ejected and then ionized by Gamma Cas. The question is if the huge dark circle surrounding it could also have been created by Gamma Cas. Is the star old enough to have flung matter so very far away from it?
Anyway. Because I've been talking about Gamma Cas the whole time now, I can't help thinking of Mama Cass from the Mamas and the Papas. So let's hear it from the Mamas and the Papas!
[youtube]https://www.youtube.com/watch?v=N-aK6JnyFmk[/youtube]
Ann