Update on C/2019Y4 April 7, 2020
(See all updates by clicking on the comets icon at the top of my home page)
Readers may remember that I wrote about this comet:
“As it nears the sun, it will brighten quickly. It could become the brightest object in the sky. However, it may just break apart and disappear.” See the text on figure 1 at This link
So, you were warned – and that last part may well be happening now. Below is a collection of all photometric (CCD) observations of Comet 2019Y4 from March 7. Below that is a graph of the distance from the comet to the Sun (orange) and from the comet to Earth (blue) for the same period. The distances are in Astronomical Units – the distance from the Earth to the Sun – about 93 Million miles
You see that:
* The comet was brightening until about April first. Then it declined rapidly until today April 7th.
* In that time, it has gotten closer to the sun, which illuminates the comet better than before and closer to the Earth – where we should see it brighter than before – even without the additional illumination by the Sun.
* See the Conclusions below the charts
- One expects a comet to lose mass as it is blown away by the solar wind – that is what makes the “tail”. That would cause a dimming due to a smaller reflective surface and smaller “gas ball” surrounding. This will be offset by brightening by being nearer to the Sun and Earth.
- In this case, the dimming is faster than the brightening due to being nearer. The comet is probably wasting away quickly – on its way to disappearing for good.
- But, I could be wrong. 🙂
- Hasta Luego, Steve
P.S. If you have any questions please use the comments section (Leave a Reply) below and I will answer for all the readers who may have had the same question. Thanks SBC
GoingWalkabout.Blog 
Thanks Steve. One Q. What does the fligth path look like, if you imaging you can stand “above” our planet system and look down, with the sun in the middle and all the planets more or less in circles around. Is it coming in like a shooting arrow or is it gradually bending itself more like a spiral towards the sun?
LikeLike
Steve, I read tonight is the super moon. What is that? and there are arguments the moon is not closer, it just appears to be.
LikeLike
The moons orbit is slightly elliptical, so it comes closer sometimes and farther sometimes. It is not a lot but the appearance is measurably larger (about 10%). When the close approach comes at a full moon, it is referred to as a “Supermoon”.
The “not really larger” part is about a different phenomenon. When the moon is high overhead it seems smaller than when it is near the horizon. That effect is all in your head.
LikeLike
I’ll include a diagram in the next update. But, for now, imagine yourself as very small and standing on an old-school LP record. The gaps between songs are the orbits of the planets. You are on the third gap and the comet is at the 4th gap but high above the LP. It will come in past all the rings and dive into the record inside Mercury’s orbit (1st gap) on May 30th. It will emerge on the bottom side and make a similar, but mirrored, exit path. It is moving at a tremendous velocity because it has been falling toward the Sun since about 1844. -Steve
LikeLike