Yeah, right! That link takes us to an open cluster in the Small Magellanic Cloud. As if Comet ZTF has visited the Small Magellanic Cloud. Well, I can do better, I think. How about this image to illustrate the concept of a picturesque star field?
But then APOD does much better. The
Comet ZTF link is great, because it takes us to a page where we can follow the comet live and see exactly where in the sky it can be seen at the moment when we look it up. This is where the comet is as I am writing this:
The bright star is Kappa Corona Borealis, a 4.8 K0III-IV orange star of some 10 solar luminosities at a distance of some 100 light-years.
The
C/2022 E3 (ZTF) link is also good, because it takes us to a Wikipedia page about the comet. It features a star chart showing the path of Comet ZTF, albeit annotated in German.
But I groaned when I read this on the Wikipedia page:
The unusual green color is likely due to presence of diatomic carbon, chiefly around the comet's head.
The unusual green color? How many color images of comet comas has the writer of the Wikipedia page seen?
The Wikipedia writer redeemed himself somewhat by writing this:
The C2 molecule, when excited by the solar ultraviolet radiation, emits mostly in infrared but its triplet state radiates at 518 nm. It is produced by photolysis of organic materials evaporated from the nucleus. It then undergoes photodissociation, with lifetime of about two days, therefore the green glow appears in the comet's head but not the tail.
Ann
[float=left][img3="Tails of Comet ZTF. Image Credit & Copyright: Jose Francisco Hernández"]https://apod.nasa.gov/apod/image/2301/CometZtf_Hernandez_960.jpg[/img3]
[/float]
[quote]APOD Robot wrote:
In the featured image taken last week in front of a [url=https://apod.nasa.gov/apod/ap191013.html]picturesque star field[/url][/quote]
Yeah, right! That link takes us to an open cluster in the Small Magellanic Cloud. As if Comet ZTF has visited the Small Magellanic Cloud. Well, I can do better, I think. How about this image to illustrate the concept of a picturesque star field? ⬇️
[float=right][img2]https://scienceparkboras.se/wp-content/uploads/2019/03/4551429-starry-sky-at-night-1000x1000.jpg[/img2][/float]
[clear][/clear]
But then APOD does much better. The [url=https://theskylive.com/c2022e3-info]Comet ZTF[/url] link is great, because it takes us to a page where we can follow the comet live and see exactly where in the sky it can be seen at the moment when we look it up. This is where the comet is as I am writing this:
[attachment=0]Comet ZTF position 9 January 2023 6 55.png[/attachment]
The bright star is Kappa Corona Borealis, a 4.8 K0III-IV orange star of some 10 solar luminosities at a distance of some 100 light-years.
The [url=https://en.wikipedia.org/wiki/C/2022_E3_(ZTF)]C/2022 E3 (ZTF)[/url] link is also good, because it takes us to a Wikipedia page about the comet. It features a star chart showing the path of Comet ZTF, albeit annotated in German.
But I groaned when I read this on the Wikipedia page:
[quote][b][size=120][color=#00BFBF]The unusual green color[/color][/size][/b] is likely due to presence of diatomic carbon, chiefly around the comet's head.[/quote]
The unusual green color? How many color images of comet comas has the writer of the Wikipedia page seen?
The Wikipedia writer redeemed himself somewhat by writing this:
[quote]The C2 molecule, when excited by the solar ultraviolet radiation, emits mostly in infrared but its triplet state radiates at 518 nm. It is produced by photolysis of organic materials evaporated from the nucleus. It then undergoes photodissociation, with lifetime of about two days, therefore the green glow appears in the comet's head but not the tail.[/quote]
Ann