Starship Asterisk*

Perseid Meteor, Red Sprites, and Nova RS Ophiuchus

Explanation: This was an unusual sky. It wasn't unusual because of the central band the Milky Way Galaxy, visible along the image left. Most dark skies show part of the Milky Way. It wasn't unusual because of the bright meteor visible on the upper right. Many images taken during last week's Perseid Meteor Shower show meteors, although this Perseid was particularly bright. This sky wasn't unusual because of the red sprites, visible on the lower right. Although this type of lightning has only been noted in the past few decades, images of sprites are becoming more common. This sky wasn't unusual because of the nova, visible just above the image center. Novas bright enough to be seen with the unaided eye occur every few years, with pictured Nova RS Ophiuchus discovered about a week ago. What was most unusual, though, was to capture all these things together, in a single night, on a single sky. The unusual sky occurred above Zacatecas, Mexico.

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“It's not unusual, it happens every day, no matter what you say”

Okay, my attempt at annotation... (This one drove me slightly crazy...)


1) IC 4756, open cluster

2) NGC 6633, open cluster

3) IC 4665, open cluster

4) The Scutum star cloud

5) NGC 6604, open cluster and nebula

6) M 16, the Eagle Nebula

7) M17, the Omega Nebula

8) M25, open cluster

9) The Small Sagittarius star cloud

10) M22, globular cluster

11) The Teapot of Sagittarius

12) The Trifid Nebula (probably partly hidden by clouds)

13) The Lagoon Nebula

14) Runaway hot star Zeta Ophiuchi with emission nebula (the nebula is not visible here)

15) M7, open cluster

16) M6, the Butterfly Cluster, open cluster

17) NGC 6357, the Lobster Nebula or War and Peace Nebula

18) NGC 6334, the Cat's Paw Nebula

19) Antares

20) Rho Ophiuchi

21) The False Comet, consisting of supergiant star Zeta1 Scorpii, bright open cluster NGC 6231 and nebula IC 4628

Phew!

Ann

Nice photo; has it all; Nova, Red Sprites, & the
Milky Way! I really like it, but I"m ready for
some other astronomy pictures! Kitty sees something in the Sky? Or maybe a birdie!

Ann, you're putting in a lot of work on these annotations. I hope you're getting paid well!

This reminds me of something my science teacher once told me. Science is a study in contrasts. It can range from the macroscopic of the very large such as life on Earth to the speed of light - and then to the microscopic, the study of bacteria to the study of atoms and subatomic particles. In a way astronomy in this picture is also a study in contrasts. From the very old and eternal such as the age of the galaxy and the stars to the very fleeting such as the meteor, the red lightning sprites which only lasts for mere seconds to the Nova which was only discovered a week ago? Just think if this picture was taken 8 days ago with the exact same time and location the Milky Way would be virtually unchanged except that the last three objects mentioned wouldn't be there including the Nova. (Or would the Nova still be there but nobody could tell it apart from all the other 10,000 points of light called permanent stars.)

NCTom wrote: ↑Mon Aug 16, 2021 12:17 pm Ann, you're putting in a lot of work on these annotations. I hope you're getting paid well!

I'm sure our collective gratitude and appreciation is all the reward she needs.

So, I presume the green beginning of the meteor trail is due to ionizing magnesium?

And about the RS Ophiuchus nova, the WikiPedia article says this about it's cause:

The recurrent nova is produced by a white dwarf star and a red giant in a binary system. About every 15 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion. The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf.

But in a YouTube video from Anton Petrov (prolific poster of new research in astronomy), he says the nova is due to thermonuclear reactions in the accretion disk! First time I've ever heard of that possibility. Is this valid or is he mistaken?

johnnydeep wrote: ↑Mon Aug 16, 2021 4:03 pm

NCTom wrote: ↑Mon Aug 16, 2021 12:17 pm Ann, you're putting in a lot of work on these annotations. I hope you're getting paid well!

I'm sure our collective gratitude and appreciation is all the reward she needs.

Exactly!

Ann

johnnydeep wrote: ↑Mon Aug 16, 2021 4:11 pm So, I presume the green beginning of the meteor trail is due to ionizing magnesium?

And about the RS Ophiuchus nova, the WikiPedia article says this about it's cause:

The recurrent nova is produced by a white dwarf star and a red giant in a binary system. About every 15 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion. The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf.

But in a YouTube video from Anton Petrov (prolific poster of new research in astronomy), he says the nova is due to thermonuclear reactions in the accretion disk! First time I've ever heard of that possibility. Is this valid or is he mistaken?

I think he is probably wrong. I have listened to quite a lot of his videos, and when he talks about things that I really understand (mostly, of course, the temperature, color and mass of different types of stars), he has said things that I know are not correct.

Ann

Ann wrote: ↑Mon Aug 16, 2021 5:36 pm

johnnydeep wrote: ↑Mon Aug 16, 2021 4:11 pm So, I presume the green beginning of the meteor trail is due to ionizing magnesium?

And about the RS Ophiuchus nova, the WikiPedia article says this about it's cause:

The recurrent nova is produced by a white dwarf star and a red giant in a binary system. About every 15 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion. The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf.

But in a YouTube video from Anton Petrov (prolific poster of new research in astronomy), he says the nova is due to thermonuclear reactions in the accretion disk! First time I've ever heard of that possibility. Is this valid or is he mistaken?

I think he is probably wrong. I have listened to quite a lot of his videos, and when he talks about things that I really understand (mostly, of course, the temperature, color and mass of different types of stars), he has said things that I know are not correct.

Ann

Yeah, I have to agree. Thinking more about it, there is no way that matter in the accretion around a white dwarf is going to be able to reach the pressure required for fusion to occur. Temperature, perhaps, but not pressure. Not so sure about the accretion disk around a black hole however, bur probably not there either. It's odd though since Anton usually points to scientific papers as references, but not this time. He must have gotten the idea from somewhere though. I doubt he just came up with it himself.