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Adric Riedel 20070904. The taxonomy of tiny stars Now with more eyestrain. Spectral Classification. A shorthand for describing many stellar properties in one easy-to-digest identifier. T emperature L uminosity C omposition. Spectral Classification.
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Adric Riedel 20070904 The taxonomy of tiny starsNow with more eyestrain
Spectral Classification • A shorthand for describing many stellar properties in one easy-to-digest identifier. Temperature Luminosity Composition
Spectral Classification • Current (Morgan, Keenan, & Kellman) general system is 2-dimensional. • Other systems exist • DA, DB, DC, DQ, DZ (white dwarfs) • WC, WN, and WO (Wolf-Rayet stars) • S, N, R (Morgan & Keenan Carbon star sequence) M4.5Ve Type Luminosity Class Notes
Why redo the M-K main sequence? • Originally done with low-resolution spectra • Traditionally ends at M2V • Subtypes are inconsistent or missing • O3, O5, O7, O8, O9, O9.5, B0 • K0, K1, K2, K3, (K4), K5, K7, M0…
Finding Standards No binaries No subdwarfs No variables None of this No giants
The New K-M sequence • 10 K types (K0V-K9V) • 19 M half-types (M0.0V-M9.0V) “G9” K0 K1 K2 K3 K4 K5 K6 K7 K8 K9 M0
The New K-M sequence K0 K1 K2 K3 K4 K5 K7 K6 Now with Photometric Colors! K8 K9 M0 M1 M2 M3 M4 M5 M6 M7 M8 M9
Notes on the new K-M system “G9” K0 K1 K2 K3 K4 K5 K6 K7 K8 K9 M0