CHAT TRANSCRIPT: FRIDAY Maggie Turnbull: (09:19) Are these slides available somewhere? Michael Pagano: (09:20) I believe all the talks and ppt should be available at a later point. Maggie Turnbull: (09:21) I jus want to look at the tau Ceti slides, this is one of the targets that I'm writing about (and planning to ask you about) in the targets paper... Marco Boldt: (09:22) Any questions? You can type them in the chat Michael Pagano: (09:22) Patrick and I have some info on Tau Ceti, I'm sure we can get you some info Maggie Turnbull: (09:22) Thanks Mike. I'll bug you later. Maggie Turnbull: (09:47) What is the connection to abundances? Anand Thirumalai 2: (09:48) Question: How sensitive are your results depending upon the opacity model? Maggie Turnbull: (09:48) Also, the "change" between these calculations and the 93 paper in HZ location is only a few hundredths of an AU. What are the errorbars? How sensitive are these limits to the exact planet parameters assumed (e.g., planet mass and atmosphere composition)? Does it really make sense to talk about a planet like HD 40307g or even Gl 581g being in "the HZ"? Anand Thirumalai 2: (09:50) I was thinking about line absorption penn state 2: (09:53) hi anand, ravi here Anand Thirumalai 2: (09:53) Hi Ravi, Anand Thirumalai 2: (09:53) Thanks for a nice presentation Tom Barclay: (09:54) A recent paper using 3D climate models differs from your result. Could you comment on this penn state 2: (09:56) thank you, anand. penn state 2: (09:57) Tom, can you tell me about that paper ? Tom Barclay: (09:57) Yes, it was a paper by Leconte penn state 2: (09:57) did they derive HZs ? Eric Gaidos: (09:58) http://arxiv.org/abs/1303.7079 Tom Barclay: (09:59) Thanks Eric penn state 2: (10:01) Thanks ! Eric Gaidos: (10:01) Note that these are "land planets" Eric Gaidos: (10:02) presumbly inhabited by land sharks Natalie Hinkel: (10:02) with lasers Eric Gaidos: (10:02) More seriously, the 3D aspect is very important as the distribution of RH with latitude controls the ability of the planet to radiate Eric Gaidos: (10:03) Drier planets with strong meridional circulation can carry heat to the drier poles and thus radiate more effectively. Maggie Turnbull: (10:03) *How* different is the result? 0.05 AU? ;-) Eric Gaidos: (10:03) I'd have to read the paper ;S penn state 2: (10:06) Thanks, Eric. ! I have to read the paper too. Anand Thirumalai 2: (10:14) What are the clumps themselves CHAT TRANSCRIPT THURSDAY MORNING made of? Is it gas+dust? CHAT TRANSCRIPT THURSDAY MORNING Anand Thirumalai 2: (10:16) Do you think your results will change with inclusion of dissipative effects, viscosity etc in addition to cooling? Eric Gaidos: (10:21) Is there a critical density enhancement (clumpiness) that is required to trigger the cooling that gives you the injection? Anand Thirumalai 2: (10:21) Thank you Evan. Eric Gaidos: (10:22) so only a factor of 2? Eric Gaidos: (10:32) Those distances are the data or the theory? Steve Desch: (10:35) Eric: the distances are well motivated by observations of H II regions (Hester & Desch 2005). It turns out not to be sensitive to distance because the entire periphery gets contaminated whether at 2 pc or 4 pc... Eric Gaidos: (10:35) I just wanted to know whether the distances belong to the data points, or to the line that he plotted Steve Desch: (10:36) Eric: as far as density goes, it's hard to observe in Cas A or other SNRs. But simulations and observations suggest a certain degree of clumpiness (see Pan et al 2012 and Ouellette et al. 2007, 2010). Strong support for clumpiness comes from presolar graphite grains of SN origin (Fedkin et al. 2009) Steve Desch: (10:36) Eric: and I was referring to Evan's talk. Sorry! Eric Gaidos: (10:48) Palin probably prefers the "bullet" scenario :| Natalie Hinkel: (10:49) =) Ariel: (10:49) Good one, Eric. ;-) Eric Gaidos: (10:50) Another constraint is the absence of significant Fe-60, as the latest measurements suggest Eric Gaidos: (10:50) significant = over what GCE background predicts Eric Gaidos: (10:51) B stars produce lots of Fe-60. Eric Gaidos: (10:52) Ed is correct Mini Wadhwa: (10:53) ACtually, both U Chicago group and our group suggest an initial 60/56 at ~10^-8 Eric Gaidos: (10:55) huh? Eric Gaidos: (10:56) Mean life is longer, I think Natalie Hinkel: (10:56) Looks what you've done. Natalie Hinkel: (10:56) *look Eric Gaidos: (10:57) Mini, you are right, but I was assuming a previous 2e-6, and current 5e-9 so a factor of 400 Mini Wadhwa: (11:02) Eric, more like a factor of 100 (assume previous 1e-6 and current that is actually a 1-1.5e-8) Mini Wadhwa: (11:07) ....but close enough on a log scale! Eric Gaidos: (11:13) ah ok, thanks Eric Gaidos: (11:13) But Phoenix is not in the HZ Elena Nickson: (11:13) It has been pouring with rain all day here (UK - Milton KeyneS) Bryce Carande: (11:15) phoenix is not in the continuously habitable zone Natalie Hinkel: (11:16) fortunately now it's a nice 25C (77F) Anand Thirumalai: (11:16) Question for Steve: Is Oxygen in Jupiter mostly in elemental form, or would it exist in various compounds? If so, would it possible that detecting some of these, perhaps not earlier detected compounds, might increase the Oxygen abundance a little bit? Eric Gaidos: (11:20) I'm not sure we know the O abundance of Jupiter - it was expected to be detected as H2O by the Galileo probe, but wasn't seen, or detected at low abundance Anand Thirumalai: (11:21) Did the probe look for CO or CO2 as well? Erik Brugamyer: (11:22) Steve: do your ice lines include the possibility of MRI-driven turbulent heating? Eric Gaidos: (11:25) deathClock? Steve Desch: (11:27) deathclock = shamelessly stolen from intertubes Steve Desch: (11:28) In Jupiter's atmosphere O is mostly in H2O. At 1 Mbar depths, though, it's atomic Steve Desch: (11:29) Erik: yeah, the MHD turbulent heating *is* the accretional heating. See Lesniak & Desch (2011). Thanks for the Q! Anand Thirumalai: (11:29) Do we have a decent estimate of how much O is there at 1Mbar depths ? Steve Desch: (11:30) Anand: should be well mixed. But there is no direct measurement, nor will there ever be one. Anand Thirumalai: (11:31) Thanks you Steve. Anand Thirumalai: (11:32) *thank Cayman Unterborn: (11:33) There was a geonutrino conference just a few weeks ago in Japan with VERY up to the date results. See: http://www.awa.tohoku.ac.jp/geoscience2013/ Eric Gaidos: (11:38) see: http://iopscience.iop.org/0004-637X/700/2/1732/ Bryce Carande: (11:38) why is "all-radiogenic" different from the standard earth curve? Eric Gaidos: (11:38) for a more detailed treatment of the problem of varing LLR abundances Cayman Unterborn: (11:43) Bryce: 40% of the Earth's heat comes from latent heat and the cooling of the earth. So if you make that proportion all radioactive, then you have to increase your abundances of U, Th and K Cayman Unterborn: (11:44) which affects your initial heat and your cooling rate starting from t=0 Bryce Carande: (11:45) ah, ok. i was wondering what that assumption was. thanks Eric Gaidos: (11:45) If he is accounting for secular cooling, then by definition it is not possible to have an "all radiogenic" case. Elizabeth Frank: (11:46) Why don't the Earth and All Radiogenic curves cross at modern heat production and 4.6 Gyr? Cayman Unterborn: (11:46) Agreed. That's the all radiogenic case for a planet with x% more radioactive nuclei Natalie Hinkel: (11:46) Did he account for the limitation of the Hill radius? I thought that in many cases the Hill radius < tidal locking distance. Elizabeth Frank: (11:47) My question refers to the heat plot Cayman is discussing. Russ Genet: (11:47) I hope to join in later on today. There is some interesting work on differences between binary stars and single stars that we don't understand well yet that visual double star astrometry and differential photometry may help with. Oleg Malkov at Moscow State Univ. has pulled together data on this. See his talk and slides at www.IADSO.org. Cayman Unterborn: (11:48) My guess is that he changed the initial abundances and scaled from there. That would mean you'd have a higher (I think it was higher, I'd like to see that plot again) heat output at ~4.5 Ga Eric Gaidos: (11:49) We also have direct samples of the upper mantle (peridotite) and hence have another constrain on U, Th, K abundances Elizabeth Frank: (11:49) The All Radiogenic curve was higher. Eric Gaidos: (11:49) I have a piece of the mantle in my office. Erik Brugamyer: (11:49) Rory: on a somewhat-related topic, do you have an opinion regarding the most likely heat source for so-called "inflated hot Jupiters"? Cayman Unterborn: (11:50) I'm not sure how much less incompatiable Th is versus U, or vice versa, but if they are close, a crustal rock should tell you Cayman Unterborn: (11:50) the ratio at least Cayman Unterborn: (11:51) In regards to radioactivity it should be noted that the ratio of radiogenic elements tells you about the timescale of which element will dominate heat output, whereas absolute abundance is what matters in whether you have enough heat to even start convection Bryce Carande: (11:52) ^ or drive convective vigor Cayman Unterborn: (11:53) And degree and timescale of a magma ocean will also affect your mantle heat budget. If you sequester all of your radionuclides in the crust then you lose a major internal heat source Eric Gaidos: (11:53) extremely low metal stars Cayman Unterborn: (11:54) See my poster for Th measurements of planet hosting and non host solar twins/analogues Inese Ivans: (11:54) Patrick: wonderfully clear explanation! Eric Gaidos: (11:55) All U, Th, K tend to partition into melts and hence tend to go into the crust, especially continental. Eric Gaidos: (11:56) ? Natalie Hinkel: (11:56) Cayman - Did you measure those abundances or pull them from literature? I didn't see any references on your poster. Cayman Unterborn: (11:56) We measured them using HARPS spectra. Natalie Hinkel: (11:56) Are they published yet? Cayman Unterborn: (11:56) Writing it up as we speak Cayman Unterborn: (11:57) Should be submitted to ApJ by the end of the month Natalie Hinkel: (11:57) Nice, I look forward to reading it (arXiv, I hope?). Cayman Unterborn: (11:58) For sure. It'll focus a lot on the implications of the variation in abundances, but there will be plenty of meaty spectral analysis methods too Bryce Carande: (11:58) Eric, even though the crustal concentrations of U, Th are way higher than the mantle values, the mantle contains a lot more by total weight? Bryce Carande: (11:58) or at least similar Eric Gaidos: (11:58) What did you measure? Cayman Unterborn: (11:59) Eric, I think that was to me, but I measured Th abundances in solar twins/analogues with and without planets. Found variation of ~.75 to ~3 times more Th relative to solar Eric Gaidos: (11:59) The partition is enough to affect the heat budget at a quantitative level (at least we think), but that is what we are trying to find out with geoneutrinos, etc. Eric Gaidos: (12:00) Yes, thanks. Please send me preprint. Eric Gaidos: (12:00) (to Cayman) FRIDAY AFTERNOON Marco Boldt: (12:00) Survey is available on your workshop experience: http://www.surveymonkey.com/s/www-stellar Cayman Unterborn: (12:00) with the majority of our sample being above solar Marco Boldt: (12:00) We appreciate your feedback Cayman Unterborn: (12:00) granted that sample is ~14 stars, but pretty interesting result none the less Eric Gaidos: (12:01) See Kite et al. 2009 for discussion of implications of this for thermal evolution of planets Natalie Hinkel: (12:01) I've seen P measurements for 20 stars....some is better than none. Eric Gaidos: (12:02) There is also some data for Eu, as Patrick highlighted. Cayman Unterborn: (12:03) It was mostly a lark to see if we could even measure the blended Th line at 4019 angstroms, so we went for publically available data and found that yeah, the variation is there. Hopefully going to follow it up (and measure U) very soon Cayman Unterborn: (12:03) *follow up with a better telescope Natalie Hinkel: (12:41) Eu is actually relatively well measured in stars (see slide 2 from my first talk yesterday) Natalie Hinkel: (12:41) However, I have yet to run across Th. University of Washington: (13:16) Please use the cursor rather than the laser pointer. We remote participants can"t see where the laser is pointing. Steve Desch: (13:18) We have discovered a technical bug: cursor doesn't show up when using Keynote! Dan is trying to describe in words what he's pointing at. Sorry! Maggie Turnbull: (13:19) What does pyroxene vs olivine mean in terms of habitability? I don't have enough geology to fully grok this. Eric Gaidos: (13:19) No one does Cayman Unterborn: (13:19) Maggie: That's an open question. Steve Desch: (13:19) Wait for it..... Maggie Turnbull: (13:19) Haha, thank you. :) University of Washington: (13:19) Got it! Rirry was apparently able to use it and he was in keynote, so it is at least possible... University of Washington: (13:20) Rory Cayman Unterborn: (13:20) It should be noted that we don't know the Mg/Si ratio for the lower mantle. Depending on who you ask you can anything from .7-1.1 Maggie Turnbull: (13:21) But not 2:1..? Eric Gaidos: (13:21) CMB melting is very controversial Cayman Unterborn: (13:22) No, that would mean equal parts perovskite and MgO, which is pretty hard to make work with geochemistry Cayman Unterborn: (13:22) And it would mean the mantle isn't very well mixed, because we've got a good idea of the upper mantle's Mg/Si Cayman Unterborn: (13:23) and it's not 2:1 Maggie Turnbull: (13:23) I don't believe that diagram, those C/O ratios are suspect. Natalie Hinkel: (13:24) all C/O ratios are suspect Eric Gaidos: (13:25) well, except that there is a temperature dependence Eric Gaidos: (13:25) so the planet will heat up until the viscosity drops and the Ra number increases Cayman Unterborn: (13:25) And does not consider diamond, which is an order of magnitude above SiC in thermal conductivity Eric Gaidos: (13:26) As long as there is a reasonable source of internal heat, planets will at least partially convect. Cayman Unterborn: (13:27) Partial convection makes it much harder to get plate tectonics, so from a habitability perspective they are pretty dead Steve Desch: (13:27) Eric: probably they will convect, but not necessarily! If the Rayleigh number is < 10^3 they don't. Eric Gaidos: (13:27) Nonsense Eric Gaidos: (13:28) Steve, the question is not what the Raleigh numbers is at a given temperature, Eric Gaidos: (13:29) but whehter thermal conduction can itself carry off all the heat that is internally generated. Nikku (Madhu) Madhusudhan: (13:29) What is the influence of the phase changes you discussed on observables such as mass and radius of super-Earths? Natalie Hinkel: (13:29) Nikku - That's a really good question. Nikku (Madhu) Madhusudhan: (13:30) Thanks Natalie. Cayman Unterborn: (13:30) Nikku: in planets that big, we know that things should be getting more compacted, so density should increase for a given composition as you increase mass. At least that's been my intuition Cayman Unterborn: (13:31) But we also have no idea what kind of phase changes you'd get. You hit the perovskite to post-perovskite transition in a 10 earth mass planet only about 25% below the surface Bryce Carande: (13:31) but we don't know much AT ALL about these minerals at high density (especially the SiC) Eric Gaidos: (13:31) absolutely. Cayman Unterborn: (13:32) so 75% of your planet is above pressures and temperatures we observe on the Earth Nikku (Madhu) Madhusudhan: (13:32) I am asking about phase changes within the silicates.. Nikku (Madhu) Madhusudhan: (13:32) NOT SiC Anand Thirumalai: (13:33) I'm just curous if in the schematic phase diagram, you don't have a peritectic point? At low Mg atomic percent? Eric Gaidos: (13:33) Well, eventually Fermi-Diract takes over the EOS and only mean MW matters Eric Gaidos: (13:33) Dirac Cayman Unterborn: (13:34) Oh man, Fermi-Dirac EOS. A shiver just ran down my spine Eric Gaidos: (13:34) Gosh, I didn't even bring up Thomas. Cayman Unterborn: (13:36) So why SiC instead of diamond? Seems if you oxidize your Si then it would be quite tough to alloy that with C Eric Gaidos: (13:37) But there is much more C than Fe Nikku (Madhu) Madhusudhan: (13:37) exactly!!! Nikku (Madhu) Madhusudhan: (13:38) order of magnitude more C than Fe Eric Gaidos: (13:38) there is graphite in carbonaceous chondrites Cayman Unterborn: (13:40) And fugacity is going to play a HUGE role in this Eric Gaidos: (13:41) There are lots of interesting carbide species in enstatites which form at low O fug Cayman Unterborn: (13:43) But is that low of fug at early planetary conditions going to play more than a local role? Seems to me that unless your O abundance is very low, you're going to have a hard time making carbides in a reasonable amount to make a difference. Eric Gaidos: (13:44) well it obviously was local for our SS. Presumably that region/time would expand with increasing C/O Eric Gaidos: (13:45) One of the complexities is exactly that heterogeneity - the midplane of the protosolar disk is thought to have been more oxidizing (because of high dust/gas ratio) than the rest of the cloud, for example. Cayman Unterborn: (13:46) Exactly. Si fug buffers are pretty low relative to carbonates. It depends on what snatches up the O first Eric Gaidos: (13:47) Fun stuff to think about , but much harder to observe/test!!!! Maggie Turnbull: (13:51) I know, that's where I'm getting stuck. How is this ultimately relevant to the real world? Especially given the huge errors in abundance measurements for stars...and that those ratios might not even be preserved in planets anyway! Cayman Unterborn: (13:58) Well, C as diamond or SiC, can have drastic effects on a planet's ability to convect due to their high thermal conductivity and viscosities. And it looks like you don't need very much to start making convection pretty sluggish. Now if you have a hotter planet, which hopefully we can judge this potential by measuring Th and U in their parent star, then it won't be a big deal, but if not then convection gets pretty dicey. Or at least getting the right viscosity profile with depth to sustain plate tectonics. Bryce Carande: (14:00) beyond plate tectonics, even stagnant-lid convection becomes questionable Cayman Unterborn: (14:01) Well, with stagnent lid you have no interior-exterior C and H recycling, which seems to be paramount in sustaining an atmosphere/ocean Bryce Carande: (14:04) Eric and Cayman, you had some interesting points on the importance of oxidation in determining what minerals condense. could you elaborate here? Erik Brugamyer: (14:05) the problem there is that observations of disks are limited Cayman Unterborn: (14:07) Fugacity at a given pressure and temperature determines the order of oxidation. Experiments show that it seems that Fe will oxidize before C, meaning if you have enough excess C you will create diamond (or SiC, but that's less evident in my opinion). This happens in the Earth, we have a small amount of excess C in the lower mantle relative to FeO-MgO-SiO2 , but it's not enough to be dynamically relevant. Cayman Unterborn: (14:08) and we see diamonds coming from the mantle in kimberlite eruptions Dan Shim: (14:09) Good point. We get SiC and C from the mantle. Dan Shim: (14:10) Sorry to join in suddenly. Cayman Unterborn: (14:13) I think there should really be more communciation between astronomers measuring these things and the mineral physicists who can put it into a mineralogical context at depth and take the next steps to see if that possible composition produces an "active" planet. We can and want to help! Michael Pagano: (14:15) Yes, agreed. Dan probably understands that now, as he has been working with us astronomers since he got to ASU, and I know it's been exciting and very informative to communicate accross those disiplines (even if I learn best when geophysicists use food analogies" Cayman Unterborn: (14:19) We do like food. Although I remember some plum pudding models being used in astronomy too... Natalie Hinkel: (14:19) Astronomers also like onions. Eric Gaidos: (14:21) Dan Shim, that was a very nice presentation, and I thought you explained major points very well to a broad audience like this one. Michael Pagano: (14:23) Yes... the idea that other stars and planets could be weird, should force all scientists to think outside the box, because who knows how normal the Earth is Kera Tucker: (14:23) I couldn't agree more! Terrestrial geologists have so much to contribute! Dan Shim: (14:23) Thanks. Wonderful to have people in virtual audience to raise very important points. Sorry not to credit these people on oxygen fugacity and other important parameters. Michael Pagano: (14:23) Even if we don't really have C/O or Mg/Si values pinned down to small errors, doesn't mean we can't use the idea to start thinking what happens inweird places Natalie Hinkel: (14:25) el - you can respond to my personal chat el: (14:26) sorry it cut off. elle kennedy cadiex, creativecommunications. http://twitter.com/creativecomm. As I'm the only person who's tweeting, let me know if I got any facts wrong and I can delete. Cheers. Natalie Hinkel: (14:26) Thanks so much! Erik Brugamyer: (14:26) On the stellar abundances front: the wealth of Kepler data/statistics can be leveraged by us only to the extent that we are able to characterize (statistically) the chemical abundances of the kepler field. This is important, since the kepler field contains a mix of thick disk and thin disk stars Erik Brugamyer: (14:27) and therefore likely differs significantly compared to the local field Elena Nickson: (14:27) I did some tweets yesterday about it using #stellarstoich Eric Gaidos: (14:28) There are ongoing efforts to gather spectra of Kepler stars - detected planet hosts as well as the others Michael Pagano: (14:28) Erik, have you seen anyone doing abundance studies on Kepler stars? Obviously it would be a great sample to use, but i wonder how many we can get great spectra on (or if people already have) Bekki Dawson: (14:28) Erik, I've heard from Kepler team members that they're working on improving the metallicity estimates for the stars using new broadband photometry in a band that is more sensitive to the metallicity. Erik Brugamyer: (14:29) Michael: right, the problem is that they're so faint that getting high-quality spectra is very challenging Natalie Hinkel: (14:29) Per Kepler, I don't imagine that we would be able to get a wide variety of element abundances for many stars, i.e., only the ones that are relatively nearby. Part of the reason why my catalog has a distance cutoff of 150pc is because it gets increasingly difficult to measure abundances (other than iron) beyond a certain distance. Michael Pagano: (14:29) Would love to see a high res spectroscopic study of the closer Kepler stars. Agreed that it would help put all this other information in context Eric Gaidos: (14:29) Broad band photometry is not useful except for the broadest brush of Fe abundance, for example, and only at very coarse precision Erik Brugamyer: (14:30) I absolutely agree with Eric regarding photometry Joleen Carlberg: (14:30) On the plus side, a lot of the follow up of Kepler targets to verify planets is done with Keck and those spectra eventually goes public in the Keck archives Bekki Dawson: (14:30) I agree but it's not going to be possible to get spectra for all 100,000 stars so it's interested to see trends with these very rough Fe estimates. Eric Gaidos: (14:30) Also, we don't have parallaxes for Kepler stars which would help us - but Gaia will help us Erik Brugamyer: (14:31) Aha! Perhaps VIRUS on HET would allow for a large sample!? Eric Gaidos: (14:32) Talk to Andrew Mann and Adam Kraus - they are proposing to do exactly that. Eric Gaidos: (14:32) HET has issues - but we digress - better for 1-1 chat Maggie Turnbull: (14:33) I think it's a great idea to get a TON of telescope time and hammer out abundances for TESS and Kepler stars, make an element database that has consistent measurements!! Eric Gaidos: (14:33) Maggie will write hte proposal Natalie Hinkel: (14:33) We will be "collaborators." Maggie Turnbull: (14:33) haha Nardo vanna Bella: (14:34) Sounds like there needs to be a robotic gathering of bright star data for TESS Eric Gaidos: (14:34) Several of us decided yesterday that observing a bunch of extremely well characterized stars (not all just like the Sun) for elemental abundances is a good next step. "Touchstone" stars. Nikku (Madhu) Madhusudhan: (14:35) I think it might be very useful to prioritize determining abundances of stars whose planets have atmospheric abundances or estimates of interior compositions. Cayman Unterborn: (14:35) Something that has been a problem in my work, is that astronomers are not necessarily aware what is going on in the big geology journals and vice versa. Is there a way to remedy this? Michael Pagano: (14:35) What do the astronomers think about an idea that was mentioned yesterday of normalizing elements to Si instead of Fe... it would have its issues, but may make it easier to talk to other disiplines that don't understand why we report it "X/Fe" Natalie Hinkel: (14:35) In other words, a number of prioritized list....with different (potentially overlapping) goals? Eric Gaidos: (14:35) Steve, this workshop has made a nice contribution to that goal. Eric Gaidos: (14:36) Mahalo! Nikku (Madhu) Madhusudhan: (14:36) Natalie, yes. Cayman Unterborn: (14:36) Or even submitting something that is a mixture of the two (geology/astronomy) and where to even submit so that both fields are aware of it. Erik Brugamyer: (14:37) Michael: I think the main problem there is the relative dearth of suitable Si lines, compared to Fe Natalie Hinkel: (14:37) Then what are some ideas for lists? Now we have "well characterized", exoplanet hosts with atmospheric data on the planet, more? Erik Brugamyer: (14:38) and then you run into the problem of log gf's, which are not at all well known for Si Nikku (Madhu) Madhusudhan: (14:38) Yes, I can give a list of 5-10 hot Jupiters which are getting good atmospheric abundances Nardo vanna Bella: (14:38) So "the list" shold be the ENTIRE list for TESS Eric Gaidos: (14:38) That's 500,000 stars Maggie Turnbull: (14:38) Top 5: eps Indi (planet?), eps Eri (planet?), 61 Cyg A&B, alpha Cen A&B(planet), and tau Ceti (planets) Nardo vanna Bella: (14:39) Yes, what would it take to get the data on 0.5M stars? Maggie Turnbull: (14:39) thanks Patrick Young: (14:39) well characterized should include stars with independently derived stellar parameters. the eclipsing binary and asteroseismology samples would be good place to start. Maggie Turnbull: (14:39) for direct imaging Michael Pagano: (14:39) Agreed Patrick! Natalie Hinkel: (14:40) Double agreed. Gerard van Belle: (14:41) Think of it this way: for Kepler, the KIC catalog was compiled, in part based on actively gathered survey data beforehand. The brightness of the Kepler stars limited it to colors, but TESS stars are sufficiently bright that a mission support telescope should be built that would automatically collect abundance spectra for these objects Joleen Carlberg: (14:42) We should also include guidelines on what people should be publishing in ternms of line lists, equivalent widhts, what details of methodolgy ,etc. since there was discussion that published work is often incomplete Erik Brugamyer: (14:42) Yes! I think it's high time the stellar abundances field was honest with itself about the consequences of using global statistical fits of synthetic to observed spectra, rather than the traditional EW approach Elena Nickson: (14:43) agreed Erik Michael Pagano: (14:43) Yes Erik, we are at a point where its not worth just using methods cause it gives results... we should be able to get the best results, the right way Erik Brugamyer: (14:44) In our rush to automate the analysis of ever-growing datasets, we ravi: (14:44) Can there be a "best-candidate" list (for TESS) based on abundance determinations to identify terrestrial planets ? or even follow up observations for characterization? Erik Brugamyer: (14:44) have lost touch with some of the underlying physics Joleen Carlberg: (14:47) There is a push in the astronomical community for dealing with the same problem for codes. Maggie Turnbull: (14:47) Erik, did Nissen's paper about the O abundances call into question any of the measurements you've personally made? Maggie Turnbull: (14:48) I know he didn't mention you specifically but just wondering if the issue is widespread. Marco Boldt: (14:49) Workshop Survey: http://www.surveymonkey.com/s/www-stellar Michael Pagano: (14:49) Maggie, lots of groups use the 6300 line, I don't think Erik did, and i didn't either, but it's used more often then not (if the 7700 triplet isn't in the spectra) Erik Brugamyer: (14:50) Maggie: I'm not sure, actually Maggie Turnbull: (14:50) thanks :) Michael Pagano: (14:50) You didn't for the HW, but oyu also did the 1/4 stars that was very low metallicity, so was the hardest to do! Would be great if you do the other 3 stars later (though i will be rewriting an email with what more specific responses i want) Natalie Hinkel: (14:50) I've found that most catalogs use the 7700 triplet Elena Nickson: (14:51) I've measured the 7700 triplet in my work Maggie Turnbull: (14:51) thanks. This has been quite the rabbit hole Natalie :) Anand Thirumalai: (14:51) Thank you! Elena Nickson: (14:52) Thank you! Erik Brugamyer: (14:52) Thank you! Kera Tucker: (14:52) Please take part in the workshop survey: http://www.surveymonkey.com/s/www-stellar Maggie Turnbull: (14:52) Great meeting!! Natalie Hinkel: (14:53) Thank you everyone!