Tag Archives: Kepler

Detecting rings around exoplanets

Figure 2 from "Detectability of planetary rings around an extrasolar planet from reflected-light photometry"
Figure 2 from "Detectability of planetary rings around an extrasolar planet from reflected-light photometry"

Just saw this on astrobites.com: Could Rings Exist Around Kepler “Warm Saturns”?

It’s a new paper on arxiv.org that follows a couple of older papers that try to pin down the detectability of rings around exoplanets.  In this case, the authors are focusing only on planets and candidate planets detected by Kepler.  Astrobites does a good job of summing up the paper, so I’ll just provide a couple of other quick-read papers and a book reference if you’re interested in learning more.

Transit Detectability of Ring Systems Around Extrasolar Giant Planets
Detectability of planetary rings around an extrasolar planet from reflected-light photometry
Planetary Rings

This latter reference, a book from the Cambridge Planetary Science series, is a good introduction to (Saturn’s) rings suitable for undergraduates.

The cost of a newly discovered planet

I get forwarded stuff.  A forward I got today is for a week-old BoingBoing post about Greg Laughlin’s “exoplanet valuation” equation.  Laughlin is essentially trying to find a way to quantitatively compare the importance of each exoplanet discovery.  In this case, he’s trying to put it in terms of dollars and cents.  I don’t see where on his site he does the derivation for the equation, and I haven’t tried running any of the numbers yet (I’m still looking for a complete list of all 1200 new candidates), but the BoingBoing post says that so far:

At the time, the exoplanet Gliese 581 c was thought to be the most Earth-like world known beyond our solar system. The equation said it was worth a measly $160. Mars fared better, priced at $14,000. And Earth? Our planet’s value emerged as nearly 5 quadrillion dollars. That’s about 100 times Earth’s yearly GDP, and perhaps, Laughlin thought, not a bad ballpark estimate for the total economic value of our world and the technological civilization it supports.

The BoingBoing link breaks down the equation, but you can find Laughlin using it everywhere on his blog.

Calling all podcasters!

I mentioned this about a month ago to this list, so I’d like to remind everyone about a great public outreach opportunity.  We’re currently signed up for several slots in the 365DaysOfAstronomy.org podcast.  This is a podcast open to submission from all over the world about any topic of interest related to astronomy.  As such, people from all over the world with hugely varying degrees of expertise download and listen to this podcast.  This is a great opportunity to get involved in public outreach, get your name out in front of the general public, as well as an important addition to your CV or grad school application.  If you’d like to know more about the site and the podcast in general, I suggest reading through their “about” page.

I started doing these as an undergrad at Columbia University.  The grad students there mobilized to establish a “Columbia Mondays” recurring series during 2009.    We did quite a bit of them, and you can find links to all of them from here.  I was thinking we could do something similar for astrobiology at JHU.  We can do podcasts on any topic you like–current events, your research, hobbies, etc–as long as you can link it back to astronomy/astrobiology in some way.  I’ve done about 6 of these myself, ranging from a discussion of the Galileo probe’s discoveries at Jupiter, the science behind detecting moons around extrasolar planets, to an exploration of my interest in the history of astronomy.

Doing a podcast requires writing a transcript, recording yourself reading the transcript, and then uploading everything to the site.  The writing part requires the most time and research, but if we do this as a collaborative effort (someone writes about an area of interest, the rest of us providing copy-edit and revisions) it should go quickly.  Then, using David Coren’s suggestion, we can record and edit the podcast at the Digital Media Center in Mattin in just a couple of hours.

We have four dates reserved on the calendar: Feb 12, April 25, Sept 26, and Nov 28.  The very first one is Darwin’s birthday.  We should do something Darwinian related.  Let me know if you’re interested in doing this first one.  We’ve got to have it submitted February 7th.

The Original Bad Boy Of Science, Tycho Brahe, turns 464 today!

Happy birthday, Tycho Brahe!  464 years ago The Man With The Golden Nose was born, and the world was never the same again.  Has there ever been anyone in the history of science who’s life has been as colorful as Tycho Brahe?  Did you know his body was exhumed last month for forensic testing to determine once and for all whether or not he was poisoned with mercury?  This sparked a lot of interest in his biography, and his name was all over the news for a couple of weeks.  Here’s three of the more interesting articles posted last month.

Was Tycho Brahe poisoned? 16th-century astronomer exhumed–again

There is no shortage of lore surrounding Tycho Brahe. For starters, the 16th-century Danish astronomer famously lost part of his nose at age 20 in a duel with another nobleman and thereafter wore a metal prosthesis on his face. Then, take this bizarre snippet from an eponymous 1890 biography of Brahe by J.L.E. Dreyer:

“Two other inmates of Tycho’s house may also be mentioned here. One was a maid of the name of Live (or Liuva) Lauridsdatter, who afterwards lived with Tycho’s sister, Sophia, and later was a sort of quack-doctor at Copenhagen where she also practised astrology, &c. She died unmarried in 1693, when she is said to have reached the ripe age of 124. The other was his fool or jester, a dwarf called Jeppe or Jep, who sat at Tycho’s feet when he was at table, and got a morsel now and then from his hand. He chattered incessantly and, according to [Brahe’s assistant] Longomontanus, was supposed to be gifted with second-sight, and his utterances were therefore listened to with some attention.”

Later in his life, as court astronomer to Emperor Rudolph II in Prague, Brahe collected some of the best observations of his day for the positions of celestial bodies in the sky, which his successor, Johannes Kepler, would later publish as The Rudolphine Tables. To top it off, Brahe died at age 54 after, as the story goes, he stayed at the table too long without relieving himself during a formal dinner, possibly bursting his bladder in the process.

The crazy life and crazier death of Tycho Brahe, history’s strangest astronomer

Brahe inherited a great deal of wealth from his foster father Jørgen, who died in 1565 when saving the King of Denmark from drowning…a rather different royal death than the one Tycho might later have experienced. Brahe is thought to have possessed as much as 1% the entire wealth of Denmark, and five times that much was spent by the Danish government on Brahe’s astronomical research.

He lived in a castle, where he kept a rather unusual group of regular entertainers. He employed a little person called Jepp, who Brahe believed possessed psychic powers. Jepp was his court jester, and spent most dinners under the table. It’s probably best not to speculate on just why Brahe preferred that arrangement. Then there was Brahe’s elk, a tame beast that Brahe kept as a prized pet. The elk met a rather bizarre end, reportedly drinking a lot of beer while visiting a nobleman on Brahe’s behalf, after which it fell down the stairs and died. Yes, that entire sentence was about an elk.

I’ve heard stories that the elk got a state funeral.

Murder! Intrigue! Astronomers?

It’s “Amadeus” meets “Da Vinci Code” meets “Hamlet,” featuring a deadly struggle for the secret of the universe between Tycho, the swashbuckling Danish nobleman with a gold-and-silver prosthetic nose, and the not-yet-famous Johannes Kepler, his frail, jealous German assistant. The story also includes an international hit man, hired after a Danish prince becomes king and suspects Brahe of sleeping with his mother (and maybe being his father!).

For comic relief, there’s a beer-drinking pet elk wandering around Tycho’s castle, as well as a jester named Jepp, a dwarf who sits under Tycho’s table and is believed to be clairvoyant.

Kepler Data Release

This week, the Kepler team released much (but not all) of their data including 306 possible planet candidates.  The team published two papers on the results.



The upshot is that, contrary to our current inventory of planets, the Kepler data is implying that small planets do indeed far outnumber the larger Jovian planets.  This has been expected but never observed up until now.  Kepler’s released candidates show approximately a 1/r^2 relationship between frequency of planets and planet radius.  The second paper goes into greater detail on 5 systems that appear to have multiple planet candidates, including one with 3 planets transiting!  As for the planet candidates that Kepler has withheld, they have 400 of the most promising (read “most dramatic” and “Earthlike”) to do another 9 months of radial velocity analysis and observing.  The smallest released candidates are at 1.5 Earth-radius and they mention that they have smaller candidates in the list of 400.  One caveat for astrobiology…all of the released candidates are in close orbits of their stars (inside Mercury’s orbit).  Perhaps longer period candidates are in the list of 400.

COROT, the French planet-finding satellite, announced another 6 planets (one of which is a probable brown dwarf) to increase their total to 15.  They also hinted that they have several hundred candidates that they are sifting through.  http://www.nature.com/news/2010/100414/full/news.2010.182.html

Expect to see the number of confirmed extrasolar planets double (and more!) in the next year!