Astronomy Exam II Flashcards

Questions and Answers

Who was Williamina Fleming?

Started as Pickering's housekeeper, hired in 1881 to do clerical work, assigned a letter to each star based on hydrogen observation in its spectra, and published under Pickering.

What was Annie Jump Cannon's significant contribution to astronomy?

She cataloged the spectra of over 225,000 stars and reordered the spectral classification system from ABQ to OBAFGKM.

What discovery did Ejnar Hertzsprung make regarding stars?

He discovered that the size of stars matters, identifying that there are giant stars and dwarf stars.

What did Henry Norris Russell study?

He studied absolute magnitudes and spectral classes of stars with known distances. Signup and view all the answers

What did Jean Foucault's pendulum demonstrate?

It demonstrated the Coriolis Effect, showing that the Earth is rotating. Signup and view all the answers

Who was John Flamsteed?

He was an English astronomer and the first Astronomer Royal who cataloged over 3,000 stars. Signup and view all the answers

What was Secchi's contribution to astronomy?

He introduced the first spectral classifications for stars. Signup and view all the answers

What is Henry Draper known for?

He took the first photo of a stellar spectrum in 1872. Signup and view all the answers

What did Edward Pickering initiate?

He initiated a program to collect photographic plate images of stars and hired women to catalog spectra. Signup and view all the answers

Black body spectra are characterized by a ______ emission of light at all wavelengths, rising steeply at short wavelengths and falling less steeply toward long wavelengths.

continuous Signup and view all the answers

What properties does light have?

All of the above Signup and view all the answers

What contributions did Annie Jump Cannon make toward a modern classification system for stars?

She classified stellar spectra and reordered the spectral sequence correlated with star temperatures. Signup and view all the answers

What logic did Ejnar Hertzsprung follow to discover the classification of stars as 'giants' and 'dwarfs'?

Hertzsprung used the motion of stars, realizing nearby stars moved faster than distant ones, identifying two types within the same spectral type. Signup and view all the answers

How did Henry Norris Russell discover the classification of some stars as giants and others as dwarfs?

Russell measured parallax to 52 stars, plotted absolute magnitudes against spectral types, revealing two groups within the same spectral class. Signup and view all the answers

Study Notes

Williamina Fleming

Began as the housekeeper for Edward Pickering; hired in 1881 for clerical work.
Developed a one-dimensional classification system based on hydrogen observation in stellar spectra, known as the Harvard classification system.

Annie Jump Cannon

Early 20th-century astronomer who catalogued spectra of over 225,000 stars.
Reorganized stellar classifications from the ABQ system to OBAFGKM with fractional gradations, ordering stars from hottest to coolest.

Ejnar Hertzsprung

Made significant discoveries regarding the luminosity and distances of stars in 1905.
Noted that faint, red/orange stars were often nearer than bright ones, illustrating the importance of star size (giant vs. dwarf).

Henry Norris Russell

Conducted a project from 1902 to 1910 to measure parallax for 52 stars, increasing known star distances.
Studied absolute magnitudes and spectral classes to understand stellar characteristics better.

Jean Foucault

Demonstrated Earth's rotation using a pendulum in 1851, revealing the Coriolis Effect.
Investigated arc spectra from carbon electrodes, correlating findings with solar spectrum lines.

John Flamsteed

The first Astronomer Royal and an English astronomer who catalogued over 3,000 stars, identifying their positions in constellations from west to east.

Secchi

Pioneered the first spectral classifications by observing differences in stellar spectra.
Although his classes were incorrectly ordered due to a lack of understanding of stellar spectra, his work laid the groundwork for future classifications.

Henry Draper

Captured the first photograph of a stellar spectrum in 1872.
Contributed significantly to astronomy through personal funding and support of research.

Edward Pickering

Observed and recorded stellar spectra and initiated the collection of photographic plate images of stars.
Employed women computers to catalog and process the extensive spectra library.

Characteristics of Black Body Spectra

Continuous light spectrum produced at all wavelengths.
Exhibits a steep rise at shorter wavelengths and a gentler decline toward longer wavelengths.

Properties of Light

Exhibits a range of colors and travels at high speeds.
Can bounce off or be absorbed by surfaces and can pass through certain materials.

Contributions of Annie Jump Cannon to Classification Systems

Restructured the existing spectral sequence into a temperature-correlated order.
Her work paved the way for the creation of the HR diagram and officially adopted in 1910.

Logic Behind Hertzsprung's Discovery of Giants vs. Dwarfs

Noted that nearby stars exhibit larger apparent motions compared to distant stars.
Identified that both high-luminosity giants and low-luminosity dwarfs could share the same spectral type (G, K, and M).

Henry Norris Russell's Method for Distinguishing Star Types

Measured the parallax of 52 stars to determine distances and absolute magnitudes.
Plotted these magnitudes against spectral types, confirming Hertzsprung's findings regarding the existence of both faint and luminous stars in the same spectral category.

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Description

Test your knowledge on key figures in astronomy with these flashcards covering Williamina Fleming and Annie Jump Cannon. This quiz delves into their contributions and the historical context of their work in stellar classification.