#something about things like 3rd anni website but also 1.5 with the 'please ask them about their story'

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Did you know that when we classify stars, we’re comparing different types of stars but also stars at different stages of their life cycles? This is the second in a two-part episode about star classifications (go listen to Part 1 if you haven’t already; or listen to this one first and then listen to Part 1, it’s not exactly spoiler territory here). In this podcast, I talk about the various ways we've chosen to interpret observational data on stars, from observing the bright sky-dots to evaluating how bright they are by comparing them to each other, and all the new things we can do with new observational techniques. Never fear, Harvard observatory’s computers make a significant appearance again in this one!

I did my best to explain everything in as comprehensible terms as possible but you can hit me up with questions if you have them! I’m also on Twitter at @HDandtheVoid if you’d rather ask me there. And go ahead and check out the podcast on iTunes, rate it or review it if you’d like, and subscribe! I’ll always post all the extras here on tumblr but iTunes is probably more convenient for downloading.

Below the cut are my sources, music credits (thanks Elena for the filler music suggestion, very on-the-nose), vocab list, and the transcript. I mention a couple of books and quote a couple people in this episode so if you want to see that written down, those sources are there as well. Let me know what you think of this episode, let me know what you think I should research next*, tell me a fun space fact… anything’s helpful!

*(My thoughts were planets or looking into a couple major astronomers; either Edmond Halley or Tycho Brahe <3 or maybeStephen Hawking? Let me know by the 23rd so I can get a podcast up by July 3rd!)

Glossary:

Charge-Coupled Device (CCD) - a device that moves an electrical charge to shift the signal between incoming photons to turn them into electron charges that can then be read as an image. It’s used in digital cameras and in astronomy for UV-to-infrared applications.

deep-sky object - any cosmological object that isn’t individual stars or something from our Solar System. It’s a classification that includes nebulae, galaxies, and star clusters, and it has its roots in amateur astronomy.

Hipparcos satellite - the European Space Agency ‘high precision parallax collecting satellite’ that operated between 1989 and 1993. It gathered astronomical and photometric data of stars and was highly accurate in positioning and cataloging the star information it acquired on its four-year mission. Its data was published in 1997 in two catalogs: the Hipparcos Catalogue, distributed in print as well as on CDs and mapped 118,218 stars; and the Tycho Catalogue, distributed only on CDs and mapped 1,058,332 stars. The Tycho-2 Catalogue was an updated version of the Tycho Catalogue made with more refined imaging techniques and re-released on CDs and online in 2000 with over 2 million stars mapped.

neutron star - a type of star that has gone supernova, when the surviving core is 1.5 to 3 solar masses and contracts into a small, very dense, very fast-spinning star.

pulsar - a type of neutron stars that spins very, very fast: a kind of variable star that emits light pulses usually between 0.0014 seconds and 8.5 seconds.

stellar photometry/photometrics - measuring the brightness of stars and the changes of brightness over time. Previously used photographic plates and visual equipment in professional observatories, but shifted after an international photoelectric system was established in 1951. Currently we use photoelectric devices, such as CCDs.

stellar spectra classification - developed at Harvard Observatory in the 20th century, a categorization of stars based on stellar surface temperatures rather than actual compositional differences, gravity, or luminosity in stars. From highest temperature to lowest, the seven main stellar types are O, B, A, F, G, K, and M. O, B, and A type stars are often referred to as early spectral types, while cool stars like G, K, and M are known as late type stars, even though these titles are based in disproven ideas about stellar evolution.

Script/Transcript

Sources:

Standard stellar types via University of College London

List/timeline of major historical star catalogs

A brief history of early star catalogs, since the International Astronomical Union made a new star catalog in 2016.

A history of the Messier list

A history of the Messier List and how amateur astronomers use it

The Messier List

A really detailed Messier List, including Messier’s own observations on the object along with what it is currently understood to be

`Deep Sky Observers Companion online database

The Caldwell List via SEDS

The Caldwell List via the Astronomical League

Translation of ‘Durchmusterung’ via PONS online translation

Some hilarious mnemonics that are an alternative to the girl-kissing one to remember the order of stellar spectra. I don't know why there’s an entire page dedicated to this but good on you, Caltech.

Photometry overview via the Astronomical Society of South Australia

Hipparcos Catalog via NASA

History of the Hipparcos satellite and subsequent catalogs via ESA

Tycho-2 Catalog via NASA

The Hipparchos and Tycho catalogues online and downloadable if you have a whole lot of storage space to put them in

The U.S. Navy’s Naval Meteorology and Oceanography Command website has a list of recommended informational catalogs, last updated in November 2004

Information on current star charts, specialized and general, and how to download them

The Research Consortium on Nearby Stars’ website, working on cataloging and characterizing all stars within 10 parsecs/32.6 light years of Earth

The Smithsonian Astrophysical Observatory star catalog, which goes to V=9. Please don’t ask me how the hell it works, I didn’t bother ordering it

Another SAO catalog via NASA’s High Energy Astrophysics Science Archive Research Center website

If you can figure out how to navigate this catalog, you should probably take over this podcast for me.

Soba, Dava. The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars. Viking: New York, 2016.

“After all, astronomers could not yet tie any given traits of stars, such as temperature or age, to the various groupings of spectral lines. What they needed was a consistent classification—a holding pattern for the stars—that would facilitate fruitful future research” (91).

“A good number of other blank spaces in her tables pointed up other lacunae, such as missing minimum values, uncertain periods, absent spectra, or questionable variable type” (113).

Annie Jump Cannon: “Since I have done almost all the world’s work in this one branch, it was necessary for me to do most of the talking” (158)

Ogilvie, Marilyn Bailey. Women in Science: Antiquity Through the Nineteenth Century. MIT P: Cambridge, MA, 1986. Located in Google Books preview.

Mack, Pamela E. “Straying from Their Orbits: Women in Astronomy in America.” In Women of Science: Righting the Record. Ed. Gabriele Kass-Simon, Patricia Farnes, Deborah Nash. Indiana U P: Bloomington, IN, 1993 (72-116). Located in Google Books preview.

Selin, Helaine. “Battani” Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures. Springer Science & Business Media: Berlin, Germany, 2011. Located in Google Books preview. 

Intro Music: ‘Better Times Will Come’ by No Luck Club off their album Prosperity

Filler Music: ‘Champagne Supernova’ by Oasis off their album (What’s the Story) Morning Glory?

Outro Music: ‘Fields of Russia’ by Mutefish off their album On Draught