A new planet? and a new policy?

This is a possible detection of a planet in the star system nearest to us.

The system is Alpha Centauri, the nearest to us, at 4.37 light years, and third brightest in our sky (after Sirius and Canopus – all three being in the southern celestial hemisphere).

The system consists of two close stars, Alpha Centauri A and B; orbiting them at great distance is a dim red dwarf, Proxima Centauri, which is for many centuries our very nearest star.  So a planet discovered in the system would be our nearest exoplanet.

The image was built up from 100 hours of infrared observations in May and June 2019, by the VLT, Very Large Telescope, at Cerro Paranal in Chile.  The article in Nature Communications would explain fully; that in the Guardian doesn’t quite.  The slanting band is caused by a coronagraph that blocked out the overwhelming light of Alpha Centauri A, whose position (I take it) is marked by the cross.  The fuzzy checkerboard of the background must be a sort of moirë pattern caused by huge magnification and extremely sensitivity to small differences in radiation, including sky glow.  The dashed circle surrounds the fuzzy peak that is slightly brighter than the others and could be caused by something.  Or perhaps not: aren’t some other fuzzy peaks slightly brighter too?  But if something, what?

It could be dust, it could be an asteroid, it could be a planet.  Some think that planets cannot form, or be in stable orbits, within such a close star system.  So the astronomers are cautious till there is confirmation.  If it is a planet, it would be Neptune-sized but within the star’s habitable zone (where water can exist in liquid form).  The astronomers will continue trying to see whether the dot moves as predicted.  They must have an estimate of its orbital elements, but the article doesn’t give its linear or angular distance from the star.

Here is my plot of the Alpha Centauri system.

See the end note about enlarging illustrations.

On the left, tilted as we see it; on the right, as it would be seen perpendicularly.  The plots are of star B around star A, though more truly they revolve around a common center of gravity.  The “primary,” A, is a Sun-like star (spectral type G); B is slightly dimmer and cooler (type K).  The grid lines are at intervals of a second of arc (1/3600 of a degree).  You can see that the two appeared closest around 2016, and are now a bit easier to “split” in the telescope, but won’t be physically closest till 2035.  The circles are sized for the brightness of the stars.  If they were at true angular size, they would be dots too small to see.  So the new planet, if it is one, is near the center (perhaps virtually at the center) of that yellow circle.

Home planet department

I’m thinking that I should try alternating astronomical and non-astronomical pieces.  Then you will know which ones to ignore if they don’t jibe with your inclinations.

May be difficult to keep up.

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ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format.  You may be able to enlarge them on your monitor.  One way: right-click, and choose “View image”, then enlarge.  Or choose “Copy image”, then put it on your desktop, then open it.  On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers).  Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.

Sometimes I make improvements or corrections to a post after publishing  it.  If you click on the title, rather than on ‘Read more’, I think you are sure to see the latest version.

This weblog maintains its right to be about astronomy or anything under the sun.