Ok so after my previous post, I was feeling pretty excited about Ruby. I talked about its power and flexibility and the exciting things that could come from it.

I also talked of Ruby’s scariness, it’s ability to terrify new programmers and potential for difficulties.

I’ve found one particular example which I’m sure shouldn’t be allowed. I can see the intention and how in experienced hands it is amazing, but I can’t unsee it’s potential for misuse.

So I’ve been trying Ruby recently, partially trying to add some substance to my CV, and partially out of curiosity. I used to be a complete python snob; I didn’t understand why anyone wouldn’t use python. It is a dynamic language so no more manual memory management (though there are plenty of advantages cough cough); duck typing deserves its own special place in hell but it is bloody convenient; the amazing standard library which is great for system administration; and many other things.

So Mac OSX has the say command, which reads out some text in the computers voice synthesis functionality. This is old news.

The new hotness is switching into the “cello” voice with say -v cello. I’s lyrical and beautiful, though reading out file names is entertaining:

say -v cello source/_posts/2013-08-24-cello-voice.markdown

This was brought to my attention through the guard-shell gem README.

I’ve been playing with Ruby quite a bit recently and I like the way a custom-looking DSL can be created from the same source language.

This means I’ve converted a lot of my tools (e.g. Makefiles) into Rakefiles and I’ve just found foreman which can manage multiple subprocesses and combine their output into a nice looking coloured console result. This is typically used to manage web processes (server, task runner, development database etc.) and is required by heroku.

Scipy contains functions for fitting equations with Python, in its scipy.optimize module. The two main ones I’ve used in the past are leastsq and curve_fit, which in itself is a convenience wrapper around leastsq.

curve_fit

For this operation you require three (four) things:

This is not a blog post as such, it’s the notes that I took during the conference split up into sections. Unfortunately there is no reference to the talk content itself; this is kept in the booklet which I have sitting next to me as I type this.

Session 1

Detecting and characterising via direct imaging

• More than 2Gyr gas giants more than 10^8 times fainter than primary
• Young stars are 10^4 - 10^7 times better than this
• Chronograph for increasing contrast
• Speckle noise a big problem
  • for speckle based data S/N does not increase with time
  • angular differential imaging
    • speckles oscillate while image rotates, but keep similar shape
    • real objects will move in the frame
• A stars good targets despite being bright
  • higher hosting fraction for giant planets for A stars (not sure about this)
  • high profile detections
  • Nielsen show low host fraction despite this
• M stars also good targets
  • despite low independent host fraction
• Typical contrasts - 10^5 at 1 arcsecond (with NICI)

Physical properties (atmospheres)

• Direct photons detected from these objects
  • reflected light and background contaminants surely?
• Colours in infra-red shows deviations from the predicted T dwarf type sequence (brightness vs colour)
  • more like L dwarfs
  • much lower surface gravity
• Direct spectra taken (!)
• Huge spectral diversity for planets even in same system
• Surface gravity strongly affecting the spectra
• Orbits of Beta Pic 2 - Chauvin et al. 2012
  • most probable semi major axis

Architecture

• Upper limits to abundance
• Cold start - less than 10% for separations 20 - 630 AU
• Hot start - less than 10% for separations 10 - 810 AU
• Gravitational instability planets rare at more than 10 AU
• Scattering planets also rare
• Sphere project - 10 - 80 more planets
• Possible detection of Super-Earth around nearby M dwarf (Crossfield, Goyon et al. 2013)

Summary

• Young exoplanets have red colours consistent with dusty clouds and non-equilibrium chemistry
• Hot start gas giant planets more than 4 MJup rare at more than 10AU

International deep planet survey

• Homogeneous analysis methods

SEEDS

• Strategic Explorations of Exoplanets and discs with Subaru
• Variety in morphology of protoplanetary discs
  • gaps, non-uniform shapes
• IRD - IR doppler instrument on Subaru
  • could be good for follow up for NGTS, investigate this
  • paper

Hershell dust evolution in discs

• SED modelling and Herschel tracing dust evolution in discs

###Planet formation in evolving protoplanetary discs

I’m currently on the plane back, flying over Canada at about 922km/h as the in-flight computer (android tablet in the back of the seat in front of me) says.

I’m sitting next to a nice chinese couple, who don’t speak a word of English. They asked me through vague hand gestures to fill out their immigration card. It was quite an ordeal!

Back home now after a good conference, got lots of nice pictures of Vancouver, but am quite tired now.

The last day has come and gone. I didn’t get time yesterday to write about it so I’m doing it now while I sit in front of the A-team in a Canadian hostel. As a side note this film looks terrible.

We had some of the most interesting talks of the day yesterday, talking about planet migration and feasibility studies. Some cool stuff but I still don’t have a disc migration based theory to explain the Rossiter-McLaughlin effect. A quite sensible talk was about the formation of hot Jupiters and how the primary migration mechanism is based on the host star (or disc) metalicity. Low metalicity stars can only cause hot Jupiters to migrate through type II migration due to lack of metals from which extra planets can be formed. High metalicity stars can support the same process, as well as dynamical formation as more planets will have formed from the protoplanetary disc. It kinda makes sense in my mind.

Today’s lectures were about… you guessed it: discs! A lot of people find them interesting apparently! Anyway the talks were ok, some good some bad. One in particular involved formation theories that seemed to explain the observed distributions well; I wanted to ask about selection effects but thought I’d find him afterwards. I didn’t have time in the end but it was very interesting.

Coffee was taken up by talking to a postdoc at UNSW about dynamical stability. We chatted for a while and it was nice. Lunch was an amazing experience: we heard about a great fish and chips place down by the harbour. It was not more than a shack and we were warned of the queues. We thought nothing of it and with a 2 hour lunch break had plenty of time. So we went down and queued for a while. A while being 1 hour 15 minutes. In the sun. I don’t get sunburnt very much but my face is quite red right now! By the time we’d finished eating it was time to return to the conference centre and resume the day. IT was fantastic food though, I’d recommend it if you’re visiting and have a couple of hours over lunch to space.

Today’s schedule was short, we had the afternoon off to do whatever we wished. Actually the conference organisers offered to put on a trip of some sort after a vote to find out the most popular choice, but that fell through as organising such a mammoth activity would be too difficult.

This session was the most relevant to me and my work, as it involved the observational side of things. We had some great talks from some friends of mine, and other colleagues in the field.