Stars rapidly changing color

[Ebuntor]

Hi everyone,

I was outside last night watching the stars and I noticed there was one star that was changing color very rapidly. It didn't move so certainly wasn't a plane or something like that.

I have heard about so called "chameleon stars" that change colors because of their temperature changes but that takes years while the star I saw changed several times every second. And it was every color of the rainbow.

Also I know about stars appearing to flicker because of atmospheric interference but in such a case the star should be hard to see yet this star was very bright. Besides atmospheric interference should make it change colors anyway (I've seen stars flicker before, but this was very different).

Is anyone here familiar with a phenomenon that can cause something like this?

Thanks in advance

 

[Christopher]

If it was changing color that quickly and was that bright, it definitely wasn't a star. It had to be something human-made. Perhaps it was a distant helicopter or something that could hover.

 

[anti-matter]

Ebuntor ...and your absolutely certain this wasn't Venus?

btw what's your location? Next time anybody observes something like that happen report it with a compass direction and how many hands above the horizon so we can check it out....and don't forget those binoculars either.

 

[Brent]

I would think maybe the atmosphere causing it to look like it was changing colors. Depending on what's in the atmo, like pollutants and stuff, it can do that. Also, when straining your eyes to look at small stuff like that, your mind can play tricks on you.

 

[PlixTixiplik]

The first star that came to mind with the description of rapidly changing color is Sirius, which does have an almost iridescent, sparkling multi-colored appearance. It's also the brightest star in the sky and is fairly prominent in the early evening sky here in the west. I'm not sure what gives it that unusual appearance, though...

-MEC

 

[Darth Picardous]

I agree. sounds like Sirius and Im assuming the poster is in the Northern hemisphere looking South. The ancient Egyptians also noticed Sirius flickered colours quite quickly. This is due to Sirius' brightness, and refractive index variations caused by atmospheric turbulence, causing the effect observed.

For southerners like me, the stars Arcturus and Capella in the North do a similar thing.

 

[Ebuntor]

PlixTixiplik said:
The first star that came to mind with the description of rapidly changing color is Sirius, which does have an almost iridescent, sparkling multi-colored appearance. It's also the brightest star in the sky and is fairly prominent in the early evening sky here in the west. I'm not sure what gives it that unusual appearance, though...

-MEC

Darth Picardous said:
I agree. sounds like Sirius and Im assuming the poster is in the Northern hemisphere looking South. The ancient Egyptians also noticed Sirius flickered colours quite quickly. This is due to Sirius' brightness, and refractive index variations caused by atmospheric turbulence, causing the effect observed.

For southerners like me, the stars Arcturus and Capella in the North do a similar thing.

anti-matter said:
Ebuntor ...and your absolutely certain this wasn't Venus?

btw what's your location? Next time anybody observes something like that happen report it with a compass direction and how many hands above the horizon so we can check it out....and don't forget those binoculars either.

Yeah I live in the Northern hemisphere and I was looking South, South-West to be exact. If it's Sirius it sure is strange I've never noticed it before, I must have watched in that direction thousands of times by now. I assume such atmospheric turbulence has occurred before.

Brent said:
I would think maybe the atmosphere causing it to look like it was changing colors. Depending on what's in the atmo, like pollutants and stuff, it can do that. Also, when straining your eyes to look at small stuff like that, your mind can play tricks on you.

Only problem with that theory is that only this single star had that specific effect while all the others were normal, even the ones that were less bright (and those should be the first that would be effected by any atmospheric effects).

If my mind was playing tricks on me why was it only this specific star? I watched the others very closely too.

Christopher said:
If it was changing color that quickly and was that bright, it definitely wasn't a star. It had to be something human-made. Perhaps it was a distant helicopter or something that could hover.

No, I watched it for nearly 15 min and later that night it had moved along with the rest of the night sky and it's position was still the same relative to the other stars.

Besides I live quite close to the coast and there are hundreds of planes flying back and forth across the sea. Also there's quite few oil platforms a few kilometers away so I'm quite accustomed to seeing points of light moving around. Planes and helicopters' lights don't make multicolored effects as far as I know.

 

[Darth Picardous]

Ebuntor said:

Besides I live quite close to the coast and there are hundreds of planes flying back and forth across the sea. Also there's quite few oil platforms a few kilometers away so I'm quite accustomed to seeing points of light moving around. Planes and helicopters' lights don't make multicolored effects as far as I know.

This effect is due to the angular size of the object being viewed. Those lights, only a few cm across and several km's away, do have a perceived angular size, thus many light rays from these objects hit your eye. Atmospheric turbulence will have minimal effect on these rays and they appear constant.
However with Sirius, being a few million km's across but 87 trillion km's away, has no angular size to the human eye and thus only one light ray from Sirius to your eye occurs.
This means any refractive difference in the Earth's atmosphere will distort the lightwave and refract away colours from the pure white of Sirius, to show yellows or even red part of the stars light (remember white is a mixture of all colours).

 

[Meredith]

A sign of impending quantum collapse of the Universe, enjoy it while you can!

 

[137th Gebirg]

IIRC, from my 2 years of astronomy, the phenomenon is known as "seeing", which is the interference and bending of light from its source by heat, dust and ice particles in the atmosphere. All these things can have an effect on the bending of visible white light and breaking it up into its component spectral frequencies.

Heat has a rippling effect, much like a mirage in the desert, bending light randomly, causing the appearance of flickering.

Dust particles will block out all but light on the lower (red) end of the spectrum - light a cigarette and blow it out next to a white wall on a bright sunny day - the shadow of the smoke will always have a reddish hue.

Ice particles will act as miniature prisms breaking up the light into rainbow colors. Sun dogs are a persistent example of this on extremely cold and mildly cloudy days.

I've seen this effect myself, also thinking it was an aircraft, but when you stare at the same point in the sky for over an hour without any movement whatsoever to make sure, it is clearly not man-made.

 

[Johnny Rico]

I saw it too, but when I saw it it was within a pattern of other lights forming an elongated triangle and it appeared to be solid between them....

No wait...that was on the History Channel... *doh*

 

[anti-matter]

Got to be Sirius.

 

[Mark de Vries]

Yea, I took a look at Sirius this morning and it was positively bouncing with turbulence Not a lot of variety in colour, but there was some, mostly white and blue.