Choosing the accretion luminosity for radiative feedback
This plot shows 'distance from the star' on the x-axis, and 'ke®/(GM/R)' on the y-axis, for different starting kinetic energies, ke(r). Ke(r) for the different curves is in terms of the 'freefall energy' at r, where freefall energy = GM/r. Thus, this plot *does not* show how the energy changes as the material falls in, it rather asks the question — if you start at r (x-axis), with energy ke(r) (different curves), what fraction of GM/R will your accretion energy be (y-axis). Note, the horizontal line shows GM/R, normalized to 1.
Let's start by considering the pink line, where a particle starts from rest a distance r away. That is,
From this, we see that even at small distances compared to a typical zone size (~1/100,000 pc), the 'error' is ~.001%. That means, unless your zone size is smaller than this size scale, wouldn't expect any noticeable deviation.
The other lines show if the particle didn't start from rest, but rather some fraction of the freefall speed it would have acquired falling to r from infinity. This shows that for any gas parcels falling onto the sink within the accretion volume, going any speed from 0 to freefall produces near agreement between the equations (again, until you get to extremely small scales).
What about for gas in the accretion volume going faster than freefall? First of all, this material should not be bound so it wouldn't be accreted anyway. But assuming it would be, here is a plot now showing curves corresponding to ke(r)>GM/r.
Here, GM/R is the x-axis. Again, this estimate holds to good accuracy over extremely small distances from the sink particle (in terms of typical simulation resolution).
Meeting update
Rad Feedback
Expect to have a model up by the end of the week
Global Collapse Modes in CF model
http://mnras.oxfordjournals.org/content/414/3/2511.full.pdf - Vazquez et al 2011
Conferences
The two conferences I would like to attend this year are:
- "Star Formation 2016" - U of Exeter - End of August - website
Registration is now open, and there is a call for abstracts:
"We invite abstracts that span the full range of our field; over five days we will have sessions covering molecular clouds, protostellar cores, young stellar clusters, protostars, and planet-forming discs."
30th April 2016: Abstract submission deadline and end of early registration 17th June 2016: Registration closes 21st August 2016: Conference begins
The final programme for the conference will be announced in early June.
- "VIALACTEA 2016. The Milky Way as a Star Formation Engine: towards a predictive Galaxy-scale model of the Star Formation Life-Cycle" - End of September - Rome - website
Mars
Check out this sweet image of Curiosity in high res
Update 1/25/16
- Applied for Kavli summer program - should hear back in a month or so.
- Watched Madhusudhan talk at PPVI, describing "current" (as of 2013) state of exoplanet research. Consisted primarily of discussion of hot Jupiters, with short sections on the end discussing hot Neptunes and super-Earths. Hot Jupiter temperature inversions based on atmospheric composition and C/O ratio, and atmospheric circulation. Hot Neptunes require either non-equ. chemistry or high metallicity to fit current data.
- Also began reading Matsakos paper.
Plan to run a couple of short test runs similar to previous post, finish Matsakos paper, and read some papers from PPVI.
Update 01/25/16 - Eddie
Nothing new to post in terms of images or movies, so here's an update on what I'm currently working on:
- Clumpy paper: Received another round of comments from Pat. Time to discuss these and figure out how best to edit the paper.
- Cooling paper: Writing up the Methods section which includes a bunch of new equations that I haven't included in any of my other papers. I'm giving myself an arbitrary deadline to have a completed first draft by the end of February.
- 3-D jet simulations: These are running on Rice's Davinci. Looks like it takes about 1 week per run (not including wait times).
- Thesis: Started putting this together. Not much writing done yet, but I have a formatted template now.
- Job search: I'm going to give a talk at the LLE on Wednesday Feb. 9th. Still need to decide which of my projects I want to present. Also, need to schedule an interview with Paul Drake's group (U. Mich.)
I think that's everything. I'm pretty busy these days…
First Run Test
Installed code on pas servers, ran with mpirun OutflowWind, 10 frames, saved output to server. Used local installation of VisIt to draw frames (after copying output locally), saved movie as png then used convert to create GIF. Added both as images to blog post (below).
Update 01/11/16 - Eddie
- Finished another round of edits for 3-D clumpy paper
- Got the 3-D pulsed jets running faster now.
- On 576 cores, I got the MHD run w/ beta = 1 to run 94 out of 120 frames in just 8 hours.
- This was at a lower resolution of 32 cells per jet radius, and the jet propagated to a distance of about 23 jet radii.
- I suspect this run would take about 6 more hours to get the full 120 frames. Meaning that a run at the desired 64 cells per jet radius should take a little over one week to finish. This is doable.
Still having issues with Visit on Grass. I hope Rich can fix the issue soon, so that I can make movies more easily.