egg|nomz|egg changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer.
<kmath>
<bofh453> ♫ If I had a hundred wishes ⏎ And only one of them could come true ⏎ I would wish that over this distance ⏎ I could be ri… https://t.co/k644muXx6R
<kmath>
<Squelchtone> noticed a rogue AP on the network, tracked it down to this water heater in a utility clpset. It has an AP built in… https://t.co/mPuODf7gLg
<bofh>
like I have one particular principle when it comes to IoTshite: you *do not* put fire on the internet. This violates that principle.
<B787_300>
UmbralRaptor: can you explain the rv method of exoplanet hunting?
<B787_300>
(also Oct 8th i will be a Udvar hazy)
<UmbralRaptor>
B787_300: short version: planet orbiting a star also drags the star around, and the star's movement can be large enough for a detectable doppler shift.
<B787_300>
... but that doppler shift would be tiny and how do you do multiple planets or is this method used to tip a transit method look
<UmbralRaptor>
For the tiny part, precise measurements (R~50-150k, carefully stabilized spectrographs and wavelength references)
<B787_300>
what is R in this context?
<UmbralRaptor>
Also hence why the first planets found were mostly hot jupiters. (high mass plus close in == few hundred m/s)
<B787_300>
also how do you do multiple planets?
<UmbralRaptor>
Spectrograph resolution/how much it spreads out the light. R = Δλ/λ
<B787_300>
So for this you would want R to be as high as possible to five you a better chance of seeing the variation? or is this one of those things were the noise in the system get the better of you.
<UmbralRaptor>
Generally multiple planets are done by fitting the biggest signal, subtracting it, and fitting the next largest, until you get to something that isn't significant.
<B787_300>
i assume AO is a necessity for small planets
<UmbralRaptor>
The noise (well, thinly spread signal) can get the better of you, but my understanding is that stellar lines don't have useful unresolved structure once you get past R~100-200k.
<B787_300>
is there a paper that analyzes the chances of detection vs "planet mass/distance" from star
<UmbralRaptor>
Note that in the present, RVs are usually used to confirm/find masses of transiting planets, so finding multiple is slightly different from a blind survey.
<B787_300>
ah i thought so
<B787_300>
just seemed difficult to know if you were seeing the effects of one planet (like a couple tons short of becoming a star jupiter) or multiple smaller planets
<UmbralRaptor>
Amusingly, there was a case recently where 3 ~statistically confirmed~ transiting planets were found to be low mass stars once the RVs c, e in.
<B787_300>
although with a long enough time period you could see the dips and the irregularities of the orbit ellipse as the planets move
<UmbralRaptor>
*came in
<UmbralRaptor>
The good news is that multiple planets will give a different signal from one planet. Lomb-Scargle analysis is usually done to see what frequencies have the most power.
<UmbralRaptor>
(Like a Fourier transform, but deals better with irregularly spaced data)
<B787_300>
so is the RV method like the transit method in that you take a spectrum and revist it every ~month (or appropriate time scale) to see if it changed?
<UmbralRaptor>
Yes for search, timings are more targeted for follow-up
<B787_300>
just out of curioisty do you compare the averaged intensity of the lines across visits to see if you caught a transit? or can spectrographs not do that
<UmbralRaptor>
Not sure that I understand the question, but ignoring atmospheres, a transit would cause even darkening across the entire spectrum. Including atmospheres, you're looking for effects that would be relatively low SNR, and would need to get very lucky with timing.
<B787_300>
UmbralRaptor: using the averaged intensity across the spectrum as a overall intensity and comparing the intenesities over time to form a pseudo light curve to look for transits
<UmbralRaptor>
I guess you *could*, but it seems like you'd gain very little for an RV survey. Compared with a transit survey, this would be laughably inefficient.
<B787_300>
well i am just saying as a second way of using the data
<B787_300>
because to do RV you obv have detailed information of what the star normally looks like
<UmbralRaptor>
Oddly enough, not as detailed as we'd like. AFAIK, people are looking into doing simultaneous photometry, though that's more for compensating for stellar activity.
* UmbralRaptor
should look into if we're using RV spectra to also get stellar properties measured to greater precision.
<UmbralRaptor>
Cheap analysis of archival data is (un)fortunately something that may become part of my brand.
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<B787_300>
Have to get data somehow right? And old data is cheap if not free, while telescope time is $$$$$$$$
<kmath>
<jbbeacham> Du #CERN, un bon Jeûne genevois à tous. It's a public holiday in the Canton of #Geneva but the Large Hadron Collide… https://t.co/VZJexje2hL
<kmath>
<rjgstone> Imagine if our poster sessions were held in public transport stations and you had to explain your research to commu… https://t.co/lCy5wwI9B6
* UmbralRaptor
imagines being in 30+ C heat staring at a highway for 8-12 hours.
<UmbralRaptor>
Or <30 F cold if it's in February.
<UmbralRaptor>
semi-related, I've attended 0 of the DC astronomy on tap events because of dealing with the commute. (though conferences held in smaller cities might do okay)
<SnoopJeDi>
UmbralRaptor, you could give a talk about Kozai! :D
<UmbralRaptor>
aaaaaaaa >_>
<bofh>
UmbralRaptor: yeah, it's interesting how that tweet immediately made me think of doing that in FR, thinking about trying that *here* is just... in this heatwave, not a fucking chance (like, I'm not sure that'd even be *safe*).
<bofh>
I'd totally attend an UmbralRaptor talk on Kozai tho
<SnoopJeDi>
same
<UmbralRaptor>
Unfortunately, egg would probably give a better talk.
<SnoopJeDi>
Even if that's true, it's quite good for you as a scientist to give talks :)
<bofh>
^
<SnoopJeDi>
*Particularly* to people who aren't scientists in your field
<bofh>
^
<SnoopJeDi>
But I'm also just poking you with the idea. Even just attending is good for the soul :)
<UmbralRaptor>
Probably the closest was doing public nights at Wakoczewski and Baker observatory
<UmbralRaptor>
Also, the implication of doing the talks by subway stations. SLIGHT PROBLEM IN US CITIES.
<SnoopJeDi>
There's a star party this Friday that aligns *perfectly* with my plans to take my gf out for dinner, so I think we'll stop by that afterwards :D
<SnoopJeDi>
...not that we'll be able to see anything except whatever's directly overhead, but
<UmbralRaptor>
Owch. Not able to get out to bortle 3-6 skies?
<SnoopJeDi>
TIL Bortle scale
<egg|zzz|egg>
UmbralRaptor: bofh: we could just have a conference at ANBO and talk to the cat,
<SnoopJeDi>
UmbralRaptor, her family actually has some land out in the rural county, so we might go camp one night and take my dinky little refractor. Maybe for the Orionids or Leonids
<UmbralRaptor>
SnoopJeDi: part of also doing some amateur astronomy
<SnoopJeDi>
and I'm told there's a clay pigeon catapult on-site, so my mossberg may come along for that trip >:)
<UmbralRaptor>
hah
<bofh>
egg|zzz|egg: seems reasonable, the cat seems to enjoy astro papers,
<kmath>
<bofh453> Simply incredible internationalization fail here, in case you ever wondered what cytokine Interleukin-1ss was:… https://t.co/JLJWstImlO
<kmath>
<bofh453> Went on a random building walk, found a pile of books to be discarded, found & (with permission) took this gem with… https://t.co/rwCJaZtGQj
<bofh>
also come to think of it, yeah, I s'pose.
<bofh>
like I usually hear it pertaining to academic texts used specifically for *classes*, but honestly people here use it for arbitrary academic book-length texts whatever their purpose or what they may contain.
<egg|zzz|egg>
bofh: yeah it does have some content before the litany of tables
<egg|zzz|egg>
15 pages :-p
<bofh>
like that top floor of Gibert Joseph we went to would be all things I'd call in EN 'textbooks'
<kmath>
<whitequark> i've just watched our cat repeatedly, deliberately, and progressively faster pick up a small glass vial by grabbing… https://t.co/DKNvnz9hKK
<kmath>
<eggleroy> @bofh453 @PLT_cheater @whitequark ß is invariant under all four normalization forms (for that matter, so is β). ⏎ Cas… https://t.co/meIYo6xC76
* UmbralRaptop
bakes egg|zzz|egg a mojicake.
<bofh>
whoops, I knew it casefolded to that but also really should've realized it was invariant under all normalization forms as it's a *capital* letter >_>
<egg|zzz|egg>
wtf no, it's lowercase
<bofh>
...RIGHT it's a ſʒ ligature.
<egg|zzz|egg>
bofh: it's ſs
<egg|zzz|egg>
well, yeah, it's a mess
<egg|zzz|egg>
it's both
<egg|zzz|egg>
!u ʒ
<Qboid>
U+0292 LATIN SMALL LETTER EZH (ʒ)
<egg|zzz|egg>
stabbity the wikipedia article misuses that codepoint for a font distinction
<bofh>
okay then why is it invariant under NFKD? I'd expect that to compatibility decompose it to 'ss' (it doesn't, I just checked UnicodeData.txt, but wht?)
<bofh>
why?*
<egg|zzz|egg>
because it's part of the orthography of modern german
<egg|zzz|egg>
it's not just a typographical distinction (in fact you even have minimal pairs)
<bofh>
*stare*
<egg|zzz|egg>
(you don't need minimal pairs for it to be orthographic rather than typographical, but it's certainly a sufficient criterion)
<rqou>
!u 阝
<Qboid>
U+961D CJK IDEOGRAPH-961D (阝)
<egg|zzz|egg>
bofh: eggsample: Mass (mass, as in the thing of which the kg is the SI unit), vs. Maß (measure)
<egg|zzz|egg>
bofh: pronunciation differs, [mas] vs. [maːs]
<bofh>
Huh, distinction on the vowel.
<bofh>
But yeah that's a minimal pair alright >_>
<egg|zzz|egg>
bofh: yeah, since the orthographic reform they use the eszett after long vowels
<egg|zzz|egg>
they used to use it pseudorandomly but in DE they actually follow orthographic reforms instead of laughing at them
<egg|zzz|egg>
silly germans :-p
<egg|zzz|egg>
bofh: anyway, it's not ſʒ, in that ʒ is https://en.wikipedia.org/wiki/Ezh which is for IPA and a few languages that are not German
<egg|zzz|egg>
bofh: it's ſz, with a glyph for z that resembles ʒ
<kmath>
<ken_lunde> The following 65 CJK Unified Ideographs—all URO—are expected to have 5 different regional glyphs in #SourceHanSans… https://t.co/2AlV0I4sj7
<kmath>
YouTube - The Impossible done on a milling machine
<egg|zzz|egg>
bofh: otoh case folding would give you il-1ss, not IL-1ss, I'm unsure how you'd get the latter
<egg|zzz|egg>
bofh: I could imagine a smart converter between ISO 646 character sets turning eszett into ss if the former isn't available in the target character set
<bofh>
https://www.ncbi.nlm.nih.gov/pubmed/19109745 okay say *what* (that moment when you're searching PubMed for charset fail and get distracted by the actual scientific results instead)