The FAST Stellar Spectral Atlas
Example spectra for all of the main sequence types of star, as well as a few rarer interesting varieties.Carbon Stars on Galaxyzoo
The Sloan Digital Sky Survey (SDSS), used by Galaxyzoo to classify galaxies, also catalogued a number of interesting celestial objects. Notably, it catalogued around 500 carbon stars, which people find periodically in the Galaxyzoo images. This thread in the forums has some interesting information.Hypervelocity Stars on Galaxyzoo
As you may have guessed back when I wrote an article about them, I have a certain fondness for hypervelocity stars. A fair few of these stellar outcasts are also to be found in the SDSS, and there's a host of information about them in this thread.Lecture Notes
It's convenient that with the internet, you can Google for lecture notes on almost any subject you might be interested in. For instance, on stellar spectra:An Atlas of Stellar Spectra
...from 1943! (The same website has a few other atlases and catalogues listed.)MAST
Archived spectra and images, including spectra from Hubble and XMM (amongst other missions), at a range of wavelengths.Exoplanet Chemistry
A preprint copy of a book chapter to be published in "Formation and Evolution of Exoplanets".JSkyCalc
A java program for calculating observing times. Available as a java applet or a downloadable .jar file....I seem to have been collecting plenty of interesting reading material lately.
Introduction to nuclear astrophysics
I haven't had a chance to look through it properly yet, but it seems to be quite a nice introduction to nuclear astrophysics. Essentially, stellar fusion, nucleosynthesis within stars and how that accounts for cosmic abundance of the chemical elements.
(Read: Why we're made from carbon and oxygen, and not boron and phosphorus.)
As it describes it as the "first lecture of this volume," I'm curious to see the rest of the topics covered -- which should hopefully be written up in due course!
The SAAO is based in Cape Town. In fact, it's based in a suburb of Cape Town known as Observatory! As you might gather, it got it's name by being the former site of an actual observatory. South Africa's first Royal Observatory, to be precise. The same site is still home to the SAAO's headquarters, but the actual telescopes have moved to a better location. They're located on a mountaintop near Sutherland. Home to some of the darkest skies on the planet, and just over 1500 metres above sea level, the majority of people who go to Sutherland fall into three categories. Sheep farmers, tourists and astronomers. The SAAO is home to a multitude of telescopes, but the most notable one has to be SALT (which, fingers crossed, I might get to use). An abbreviation for South African Large Telescope, SALT is currently about the 5th largest optical telescope in the world and hosts some of the worlds best astronomical spectroscopic tools. It also holds the accolade that when it was built, particular concern was given to internet connectivity. As a result, the telescope has a 1.5 Mbit internet connection for downloading and uploading data. If I remember rightly, it also has full Wi Fi connectivity (although I could be mistaken about that part).
All the same, even if I don't get to use SALT and have to use the 1.9m Radcliffe Telescope instead, I'm not going to complain. I'm still eagerly looking forward to South Africa and some truly dark night skies. And although English is the language of choice in academic circles, the country actually has 11 official languages. Perhaps I should learn some Xhosa or Afrikaans...
I'm actually here to sort out my lab demonstration training. Due to communication mix ups a couple of weeks back I wasn't actually able to attend the proper training session last week. But there's not an awful lot to go over, to be honest. The bulk of it is going to be tomorrow. Tomorrow afternoon is a free block in the lab schedule, which is my chance to run amok and get the hang of all the lovely pieces of equipment like isoteniscopes and cannisters of helium gas. Delicious.
Bizarrely, looking over these first year lab manuals and first year experiments rather brings back some nostalgia of being an undergrad. This should be interesting. Teaching is fun!
- ♪ Music:Ellen McLain - Still Alive (Theme from Portal)
| Topics to brush up on: |
I've already written about most of those topics. You'd be amazed at how well things stick in your mind after you write an article about them. Couple of things to revise. Nothing I can't handle. This should be fun!
Admittedly, I'm also busy writing a paper at the moment. But then, I never had much trouble with multitasking. Actually, I rather enjoy having two things going on at once... Variety. Spice of life, and all of that.
- ♪ Music:Muse - Starlight
Evidently there's more than one bridge across the inderdisciplinary divide. Lately, I've been wondering precisely which one I'm standing on. Simply, am I an astrochemist or a molecular astrophysicist? Now, I'm sure that might sound a bit like I'm splitting hairs. Allow me to elaborate...
Astrochemistry
- a branch of astronomy and chemistry dealing with the chemical composition and evolution of the universe and its parts.
- the study of the abundance and reactions of chemical elements and molecules in space, and their interaction with radiation
- the chemistry of stars and interstellar space.
Molecular Astrophysics
- the study of interstellar atoms and molecules and their interaction with radiation
- the study of [spectroscopic lines] from molecules in space.
(Various sources)
Evidently, both are very similar. Both rely on spectroscopy to examine molecular lines in starlight, and both require a sound knowledge of both astronomy and chemistry in order to work. The difference, seemingly, is in the application rather than the method. The only distinction would be whether you're looking to understand the physics or the chemistry of interstellar space. My problem is that I aim to do both. Oh dear. No wonder I'm confused...
Perhaps I should be happy in the knowledge that these interdisciplinary subjects aren't mutually exclusive. In fact, it's reassuring to know that I can hop from one to the other if need be. But what exactly does "interdisciplinary" even mean? And what about all of those other, similar sounding words that seem to get thrown around?
It's a bit of a buzzword at the moment, and using it in research proposals can help to get you funded, but the intricacies of working between disciplines can be, at best, esoteric. Surprisingly, the Wikipedia article is quite informative (while still cautioning that these terms are still developing and thus the definitions are not yet universally accepted). Simply, it defines the following four terms:
Interdisciplinarity
An interdisciplinary community or project is made up of people from multiple disciplines and professions who are engaged in creating and applying new knowledge as they work together as equal stakeholders in addressing a common challenge.
An interdisciplinarary person is a person with degrees from one or more academic disciplines with additional interactional expertise in one or more additional academic disciplines, and new knowledge that is claimed by more than one discipline.
Multidisciplinarity
Multidisciplinarity is the act of joining together two or more disciplines without integration. Each discipline yields discipline specific results while any integration would be left to a third party observer.
A multidisciplinary person is a person with degrees from two or more academic disciplines, so one person can take the place of two or more people in a multidisciplinary community or project team.
Transdisciplinarity
Usage suggests that a transdisciplinary approach dissolves boundaries between disciplines. Most uses of the term suggest a deliberate and intentionally scandalous or transgressive violation of disciplinary rules, for the purpose of achieving new insight, or of expanding the discipline's resources. A less polemic view of transdiciplinarity treats it as the act of taking theories and methods which exist independently of several disciplines and applying them to organize and understand different areas or fields.
A transdisciplinary community or project is made up of transdisciplinary professionals, which is an ideal that can only be approached and never achieved. A transdisciplinary professional has degrees in all disciplines as well as experience in all professions. In essence, a truly transdisciplinary person contains all the distributed knowledge of the people in the community or project as their individual common knowledge.
Crossdisciplinarity
Crossdisciplinarity is the act of crossing disciplinary boundaries to explain one subject in the terms of another, foreign subject or method. Common examples of crossdisciplinary approaches are studies of the physics of music or the politics of literature.
So to summarise. Interdisciplinary refers to a symbiosis of more than one academic discipline, where both benefit from working together, and both claim the new knowledge obtained. Multidisciplinary is a bit more parasitic, where the disciplines work together but each only has it's own interests at heart. Transdisciplinary refers to a philosophical ideal of being educated in all disciplines. A polymath, effectively. Crossdisciplinary is poaching someone else's concepts and applying your own ideas to them.
Interesting. Very interesting. It would seem, therefore, that astrochemistry certainly meets the definition of interdisciplinary work. Both chemistry and astronomy are furthered in the process, and both seem to (at least mostly) work together quite well. Molecular astrophysics could be said to be similar, taking the principles of molecular spectroscopy and using them to further the understanding of astrophysics.
Unfortunately, despite all of this, I still haven't managed to answer my own question. In truth, I'm probably much more astrochemist than astrophysicist, though one of the ultimate goals of understanding the chemistry out there is to better understand the physics. My only whimsical conclusion is that if the person I'm sitting next to on a plane asks me what I do, I have an array of possible answers depending on how impressive I want to sound and whether or not I feel like having a conversation!
(Note: if you don't feel like talking, say you're a physicist. Most people will shun you. Including some physicists.)
Gamma ray bursts then... Ok, so around 15 slides with around 2 minutes of schpiel each should give a decent half hour. Should. Assuming I don't mess up, freeze up or ramble for too long. The GRB slides and the chemical slides are all essentially done, and thankfully I can babble for a great length of time about both. Actually, GRBs are pretty damn fascinating. In my humble opinion, molecular spectroscopy is pretty fascinating too, though I suspect less people would be inclined to agree with me on that. And if people find chemistry boring, well... At least my slides look funky. The graphic designer in me can't help that -- it's force of habit now!
Now... Just the slides on the observational side of things to go. Unfortunately, having been totally immersed in theoretical chemistry for the past n2 weeks, that's proving marginally less than trivial. Shouldn't be a problem though.
Next week's talk shouldn't be so bad. That's actually about my work. If anything, I'll have to be careful not to talk for too long about that...
I'm a little nervous about talking to a group of astronomers about molecular spectroscopy. Especially as, frankly, I have utterly no idea how much chemistry everyone actually knows!
Ah, the perils of being interdisciplinary.
TD-DFT calculations of electronic spectra of hydrogenated protonated polycyclic aromatic hydrocarbon (PAH) molecules: implications for the origin of the diffuse interstellar bands?
M. Hammonds, A. Pathak, P. J. Sarre, Phys. Chem. Chem. Phys. (in press), 2009
Abstract
We report the application of time-dependent density functional theory (TD-DFT) to the calculation of electronic spectra of hydrogenated protonated polycyclic aromatic hydrocarbon (PAH) molecules. The hydrogen atoms lie on the periphery of the PAH structure and those considered here may be written Hn-HPAH+, where n is even. It is found, in common with protonated PAH molecules, HPAH+, that some of the electronic transitions fall in the visible spectral region. The implications of the results are discussed in the context of the long-standing enigmatic astronomical problem of the diffuse interstellar absorption bands.
DOI:10.1039/b903237a
Accepted for publication before I even start on a full PhD. Even better, when the issue is actually printed, it might get featured as a "Hot Article"! Now that just rocks!
(And yeah, the journal is Physical Chemistry Chemical Physics. So that abstract might sound rather intimidating...)
Life is but a dream
Supernova Condensate is a blog about our place in the Universe; astronomy, chemistry and life in the great bubble of academia.
Invader Xan is a proto-astrochemist, trying to figure out how to be a scientist. He looks for molecules in space and studies the sciences of all things very big and very small.
He also finds it a bit weird talking about himself in the third person.
"When I am working on a problem I never think about beauty. I only think about how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong."
-- R Buckminster Fuller
Disclaimer:
The opinions expressed in this blog are solely those of the author. These views are not necessarily shared by any colleagues, coauthors, research groups or academic institutions with whom the author is associated.
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