1 / 6

Chapter 25: Beyond our Solar system

Chapter 25: Beyond our Solar system. Pages 700 - 721. Characteristics of Stars. Star color is an indication of temperature Very hot stars (30,000 K) emit high-energy, low wavelength radiation. What color do they appear? Blue

alexandria-anagnos
Download Presentation

Chapter 25: Beyond our Solar system

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 25: Beyond our Solar system Pages 700 - 721

  2. Characteristics of Stars • Star color is an indication of temperature • Very hot stars (30,000 K) emit high-energy, low wavelength radiation. What color do they appear? • Blue • Middle or average temp. stars (5000 – 6000 K) appearYellowlike our sun • Cooler stars (< 5000 K) emit low-energy, large wavelength radiation. What color do they appear? • Red

  3. Mass of Stars • Difficult to calculate • Unless the star is part of a pair • Binary stars – two stars revolving around a common center of mass under their mutual gravitational attraction • More than 50% of stars occur in pairs or multiples • Stars of equal mass will be equidistant from the center of mass • If stars’ mass is not equal, the center of mass will be closer to the more massive of the two • If the sizes of their orbits are known mass can be calculated • Binary Sunset

  4. Measuring Distance to Stars • Stellar parallax – slight shifting in the apparent position of a nearby star due to the orbital motion of Earth • Thumb’s up demo • Nearest stars have largest parallax effect • Stellar Parallax Simulator • This method only works with stars that are relatively close to Earth (within 100 light-years) • Of the billions of stars in the Milky Way galaxy, only about 700 are within parallax range

  5. Distance to the Stars • 1,000 m = 1 km • 150,000,000 km = 1 AU = 93,000,000 miles • Distances between stars are so large we need an even bigger standard of measure • Light-year – the distance light travels in one year • 1 light-year = 9,500,000,000,000 km (9.5 trillion) • Proxima Centauri, our nearest stellar neighbor, is 4.3 light-years away • How far is that in km? • 40,850,000,000,000 km!!

  6. Stellar Brightness • The measure of a stars brightness is its magnitude • Apparent magnitude – a star’s brightness as it appears from Earth; affected by three factors • How big it is; larger = brighter • How hot it is; hotter = brighter • How far it is away; closer = brighter • Absolute magnitude – brightness of a star if it were viewed from 32.6 light-years; compares true brightness • Large negative numbers are bright, large positive numbers are dim • For our sun; • Apparent magnitude = -26.7 • Absolute magnitude = 5.0

More Related