… but like the phrase goes, you really had to have been there. Literally.
The Cassini Saturn orbiter took some amazing shots of the bright star Antares passing behind Saturn’s myriad rings. I’d talk all about it, but Emily’s got the poop.
-
About Bad Astronomy
Phil Plait, the creator of Bad Astronomy, is an astronomer, lecturer, and author. After ten years working on Hubble Space Telescope and six more working on astronomy education, he struck out on his own as a writer. He's written two books, dozens of magazine articles, and 12 bazillion blog articles. He is a skeptic and fights the abuse of science, but his true love is praising the wonders of real science.
The original BA site (with the Moon Hoax debunking, movie reviews, and all that) can be found here.
Contact me: The Bad Astronomer "at" gmail "dot" com
Bad Astronomy was chosen as one of Time.com's Best Blogs of 2009. Science Getaways
Subscribe to BA
Death from the Skies!
Order a copy of Death from the Skies! from Amazon, or Barnes and Noble.
"If things worked the way I wanted them to, any reporter about to do another 'sensational' story on deadly meteors would consult this volume, and bang! common sense would find its way into the news. How strange would that world be?"
-- Adam Savage, Mythbusters
"Reading this book is like getting punched in the face by Carl Sagan. Frightening, but oddly exhilarating."
-- Daniel H. Wilson, author of How to Survive a Robot UprisingSocial/Networking/Cool Stuff
DISCOVERmagazine.com: Latest Articles on Space- DISCOVER Blogs: The Loom
- A Planet of Viruses: Autographed Book Sale
- Animal Friendships: My cover story for Time magazine
- The Future of E-books–podcast of my interview on Wisconsin Public Radio
- Thursday, February 16: Science and social media panel in New York
- A Scientific Jonah: My profile of Joy Reidenberg in tomorrow’s New York Times
Copyright © 2012, Kalmbach Publishing Co.
Privacy - Terms - Reader Services - Subscribe Today - Advertise - About Us
January 5th, 2008 at 11:30 am
I guess this proves that astronomers do dabble in the occult(ation).
January 5th, 2008 at 11:45 am
That was one great shot from the Cassini space craft. I really enjoyed it.
January 5th, 2008 at 11:52 am
A beautiful example of just how thin those rings really are.
I wonder what the average distance is between objects in the asteroid belt???
gary 7
January 5th, 2008 at 12:49 pm
The only question I have, is why do no other stars appear in other shots? You may have covered this topic before, so sorry for the repeat. However, that is one cool image!
January 5th, 2008 at 12:50 pm
I don’t remember seeing that panaroma of the ring system before. Wow! Cassini has never failed to amaze me…right from the first images back in 2004 that left me spellbound to this occultation.
January 5th, 2008 at 1:01 pm
Michael,
Most images don’t show stars because the exposures are optimized for other, brighter objects, usually Saturn & its moons. Antares showed up in that sequence because it’s much brighter than all the other stars in that field. In fact, it was photographed in this instance for measuring the texture of the ring particles, in which case the exposure was adjusted especially to get good images of Antares as its brightness fluctuated behind the thin rings.
January 5th, 2008 at 1:11 pm
Holy… guacamole… that’s… cool!
January 5th, 2008 at 1:35 pm
My first thought (which is the same thought when BA posted the news of the possible meteor impact with Mars) was whether the occultation from such a bright star would allow for some spectrometry do be done. It would help answer some of the questions about the composition of the rings and even help us find out why they’re so different. Emily was ahead of me:
>>The “real” data will presumably come from other instruments,
>>particularly the spectrometers VIMS and UVIS.
Yay!
Occultations of bright stars by rings are very useful. If I recall correctly, that is how we found the rings of Uranus.
January 5th, 2008 at 2:02 pm
Thanks, Mark!
January 5th, 2008 at 4:43 pm
I’m not sure about nowadays, but Lowell Observatory used to keep a small fleet of mobile telescopes ready for observing stellar occultations. It’d be calculated in advance where the shadow of some foreground object (planet, asteroid) would fall upon Earth, and if it was within some manageable distance of the observatory, a team with a ‘scope would be dispatched to do the photometry.
January 5th, 2008 at 5:17 pm
enjoy the rings while you can…
when the new world order turns saturn into a new star using cassini, the rings will be a thing of the past… and so will we! lol
January 6th, 2008 at 4:40 am
Emily mentioned UV spectrometry. I was wondering, how much UV does a red supergiant like Antares emit? Wouldn’t one of the optically dimmer, bluer stars is Scorpio be of more use?
January 6th, 2008 at 7:16 pm
Phil Plait & Emily – thanks, fantastic images! Wonderful science!
MandyDax : Your recollection is correct – Ouranos (proper greek spelling for only planet named for Greek rather than Roman god) was the first planet other than Saturn found to have rings by this stellar occultation technique – before the star reached the planet it “blinked out” six or so times, was then occulted by Ouranos then repeated the “blinking out” process in reverse on the way out!
If my memory serves this observationwas actuallydoen with teh Kuiper airborne (airtcraft based) observatory…
Later Voyager (I?) discovered Jupiter’s fainter rings and Voyager II discovered therings of Neptune although faint ring arcs round the latter planet were already known from earth-bound ‘scopes.
# Gary Ansorgeon 05 Jan 2008 at 11:52 am
“A beautiful example of just how thin those rings really are. I wonder what the average distance is between objects in the asteroid belt???”
Very, very considerable.
If you are on or orbiting an asteroid even in the thicker regions of the main belt then you are most UNlikely to see even one other asteroid even as a faint “star” Well, except for binary asteroids (eg. Hektor) and asteroid moons (eg. Sylvia) that is!
January 6th, 2008 at 7:37 pm
# Lab Lemmingon 06 Jan 2008 at 4:40 am wrote :
“Emily mentioned UV spectrometry. I was wondering, how much UV does a red supergiant like Antares emit? Wouldn’t one of the optically dimmer, bluer stars is Scorpio be of more use?”
Perhaps – But they’re not as bright (Antares is the 14th brightets star in the entire sky – not counting our Sun) and may not have been in the right position to be occulted. The nearest brightish star to Antares being Alniyat (sigma Scorpii?) is a blue-white B-type star but it is at best, second magnitude …
Think they used visual rather than UV for the images at least anyhow.
Oddly enough some less blue stars do still emit considerable UV if Irecall right …
Canopus a yellow-white F0 supergiant has had its hot corona detected in X-rays (& UV?) and some orange giant stars notably Diphda / Deneb Kaitos (= Beta Ceti) have anomalously high X-ray /UV (?) emissions ..
January 6th, 2008 at 7:48 pm
See James Kaler’s website & books notably “the !00 Greatest Stars” book Copernicus Press,200? & websearch under Kaler (uni. of Illinois I think, .. ) for more …
January 6th, 2008 at 10:47 pm
At home now so if its ok with the BA to quote my sources (& I would certainly recomend Emeritus Professor James Kaler’s website & books)
Kaler’s stars incl. Star-of-the Week :
http://www.astro.uiuc.edu/~kaler/sow/sowlist.html
Via there Canopus : http://www.astro.uiuc.edu/~kaler/sow/canopus.html
& Deneb Kaitos : http://www.astro.uiuc.edu/~kaler/sow/denebkaitos.html
(aka Diphda, aka Beta Ceti)
Plus the book mentioned =
Kaler, James B., ’The Hundred Greatest Stars’, Copernicus books, 2002.
A bit off thread I know but worth checking out – and again, thanks BA for the great pictures & an awesome website.
PS. Checked on the discovery of the rings of Ouranos too – it was 1977 rather than 79 so I was a couple of years off but it was the Kuiper Airborne Observatory that made the initial discovery later ring systems -incl. more around Ouranos were made by the Voyager spaceprobes.
———-
Apologies for any typos – hope the links work & all netiquette is correct.
January 7th, 2008 at 6:11 am
Antares is a lovely star to observe. I just wish SF writers would stop putting Earthlike planets around it. And Rigel, Betelgeuse, Sirius, etc. I blame Gene Roddenberry — he actually had his tech advisor explain why stars like that couldn’t have habitable planets, and he ignored the advice because those stars had better “name recognition.” Jeesh. What’s wrong with a name like 18 Eta Cassiopeiae or Mu Arae?
January 8th, 2008 at 3:55 am
StevoR:
Of course Canopus will have UV. An F is bluer than a G5, and the nearest G5 puts out enough UV to have turned me into a red giant last weekend while I was lying on the beach…
January 8th, 2008 at 6:25 am
What you got sunburn form .. er .. Delta Pavonis!
The Sun is a G2 V star. (the V indicating its main-sequence or dwarf nature rather than being a giant or supergiant ..)
You must have very sensitive skin!
I can see both sides of Roddenberry and the whole naming issue.
Yes, with a few exceptions most sun-like stars will have dull, un-memmorable calogue names while most named stars are considerably hotter, brighter, shorter-livedand unlikely to have habitable worlds around them…
OTOH how awkward is it to have aliens from HD 112399234654 or suchlike? By the time you’ finished saying :
“Sir, the Haitch D one-one-two-three-nine-nine-two-thre-four-six-five-four-eans* are attacking!”
You’d be vapor!
At least Roddenberry uses real if unlikely stars – and nowhere does it say the aliens must _originate_ from such stars … Perhaps they just moved inand (alien-equiv.) terraformed the places ..?
Simple answer : Give these stars official but proper _real_ names ! Esp. if a decent exoplanet’s found orbiting them!
—————————–
* Of course that’s only the easiest possible prounciation : “eleven gazillion two trillion, three .. ah stuff it!”
January 8th, 2008 at 11:10 am
Speculation about UV occulations aside, that was a VIMS stellar occultation. (It’s possible that UVIS was riding along, but it was meant for VIMS.) Also, I’m pretty sure that UVIS doesn’t do spectrometry during an occultation, just photometry. There’s a special part of the UVIS instrument that handles the fast-readout needed to do that. At the rate required I don’t believe it can afford to split up photons spectroscopically.