Astronomy 1020-HSpring_2015

Day-27Stellar Astronomy

Understanding the meaning behind stellar data took decades, and the contributions of dozens of people, all working toward a common goal.

PROCESS OF SCIENCEPROCESS OF SCIENCE

Course Announcements

• Smartworks Chapter 13: Friday-ish• No Class Friday (Good Friday)

• Smartworks Chapter 14: Next Week• Apr. 2 – Last day to drop a class.• 2 Dark night observing sessions left:

• Mon. Apr. 13 & Thurs. Apr. 16

• Reports are due Wed. Apr. 22• Solar Rotation Project due Mon. Apr. 27

Astronomy in the Fall, 2015

ASTR-1010/1011 - Planetary Astronomy + Lab (H,R)ASTR-1020/1021 - Stellar Astronomy + Lab (R)ASTR-2010 - Problems in Planet AstronomyASTR-2011 - Intro. to Observational AstronomyASTR-4000/4001 – Astrophotography & LabASTR-3030/3031 – Methods & Techniques in Astronomy(*)ASTR-4170 – Special Topics in Astronomy (?)

Photometry and Filter Systems

Eclipsing binary: The total light coming from the star system decreases when one star passes in front of the other.

Could also potentially measure the radii of the stars in these systems.

Masses of stars can directly be calculated if they are in an eclipsing binary system.

Using observations of the orbital periods and velocities with Newton’s formulation of Kepler’s Third law:

MATH TOOLS 13.3MATH TOOLS 13.3

Binary StarsLecture Tutorial pg. 121

Work with a partner!Read the instructions and questions carefully.Discuss the concepts and your answers with

one another. Take time to understand it now!!!!Come to a consensus answer you both agree on

and write complete thoughts into your LT.If you get stuck or are not sure of your answer,

ask another group.

H-R diagram (named for Hertzsprung and Russell) is a plot of luminosity vs. temperature.

Key to unraveling stellar evolution: how stars change with time.

Most stars exist on the main sequence.

Runs from luminous/hot to low-luminosity/cool.

Massive main sequence stars are large, luminous, and hot.

The Sun is on the main sequence.

Knowing a star’s spectral type and position on the H-R diagram allows you to know its luminosity and find its distance (spectroscopic parallax).

The mass of a star determines its fate.

H-R DiagramLecture Tutorial pg. 117

Work with a partner!Read the instructions and questions carefully.Discuss the concepts and your answers with

one another. Take time to understand it now!!!!Come to a consensus answer you both agree on

and write complete thoughts into your LT.If you get stuck or are not sure of your answer,

ask another group.

Doodle space

For distance in parsecs:

m - M = 5 log(d) – 5

or

d = 10[(m – M + 5)/5]

Spectroscopic ParallaxLecture Tutorial pg. 45

Work with a partner!Read the instructions and questions carefully.Discuss the concepts and your answers with

one another. Take time to understand it now!!!!Come to a consensus answer you both agree on

and write complete thoughts into your LT.If you get stuck or are not sure of your answer,

ask another group.