A sequences of images of the star Sirius. Source: Amanda Cross

Twinkle Twinkle little star
How I wonder what you are

Different from those nearby
Like a sparkler in the sky

Red, green, blue, and white
Sparkling all through the night

They say it’s distortion of air
But I don’t think that’s fair

Stars like Vega and Antares
Alpha Centauri and Sirius

All of you so far apart
Yet sparkle a similar lot

I read all your fables
And made long tables

Found no numbers in common
But all covered by a cloud curtain

Filtering some of your light
Creating a show in the night

Twinkle Twinkle little star
I no more wonder what you are

Up above the world so high
Like a diamond lit by a firefly

Your light comes here weak and strong
Distortion by air? I think that’s wrong

It’s definitely in the air
But the cloud is elsewhere!

This poem is my hypothesis on why some stars like Alpha Centauri and Sirius twinkle a lot compared to stars and planets of similar magnitude, lower or higher magnitude. And also when compared to other stars nearby them in the sky.

The twinkle is commonly explained away by atmospheric distortion. But if that’s the case, nearby weaker magnitude stars should have more distortion. We don’t see that. Similarly planets like Venus, Jupiter, or Saturn do not twinkle even if they are near Sirius or Antares.

I analyzed these stars, and all their parameters. Nothing seems particularly common. But I did find most of them have a dust cloud nearby.

So I propose an hypothesis that this dust cloud, between us and the star, scatters and absorbs some of the light of the star. The resulting light, which will still not twinkle when seen from space, will be scattered much more by our atmosphere. Causing a sparkling twinkle for these stars.

Vega, Antares, Alpha Centauri all seem to have dust clouds near them. But there’s no such finding for Sirius. Hence I propose Sirius too has a dust cloud between it and the Earth which is not yet found. This cloud may be moving relatively as Sirius and the Sun move over time.

In olden days, centuries ago, this cloud may have hidden Sirius more. Absorbing or scattering most of its blue light letting only the red wavelengths come through. This may explain why Sirius was considered a red star by our ancients.

I also propose that a few of the red stars we see now may not be red giants after all. They may have their light passing through such dust clouds that scatter away most blue light leaving the star looking red.

A blogs a worldview at ablogs.medium.com

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store