Transcript Astronomy - Wappingers Central School District

Astronomy:
Here is my powerpoint from last years coaches
conference. I will be updating it to reflect the
changes in content in this years rules. I’m not
sure yet how to test 50 teams at States on the
use of DS9 image viewing software, and won’t
use it at all for regionals.
Finding celestial objects
(hyperphysics.phy-astr.gsu.edu)
Finding celestial objects
( burro.cwru.edu)
Parallax
Parallax

Stellar parallax: angle abc

Parallax angle: ½ angle abc

Parsec: distance to a star with 1” parallax angle

Parsec: ~31 trillion km (19 trillion miles)

Parsec: 3.26 light years
Parallax

Star's distance (pc) = 1 / parllax (“)

Useful for stars up to about 100pc
Magnitude



Apparent magnitude (m)

Hipparchus 1 to 6

Lower numbers brighter
Absolute magnitude (M)

Corrected to standard distance of 10pc

Can be determined form spectra
Distance modulus: m – M
Hertzsprung & Russel; not vampires
Stellar Motion
Red shifting
(from the corner of her mouth)
Hubble Constant

v = Hd

Ho = ~ 74 km/sec/Mpc (~ 23 km/sec/MLY)
Age of universe

v = Hd

H = v/d

1/H = d/v = time

1/Ho = age of the universe
Schwarzschild radius (Rs)

Radius to become a black hole

Rs = 2GM/c2


G = gravitational constant

M = mass of the body

C = speed of light
Object > 3 solar masses become black holes
Wien & Stefan-Boltzman

λmax = 0.3/T


T = temperature in Kelvin
Total energy emitted is proportional to the fourth
power of the absolute temperature

A star 2x sun's temperature emits 16x more
energy

24 = 16
Open Clusters

100 to 10,000 loosely packed

Concentrated in spiral arms

Young

Hot

Highly luminous

Like certain vampires
Globular Clusters

In halo around galactic disk

100,000 to 1 million tightly packed stars

Old stars (like Lon Chaney Jr)
Population I Stars

Hottest & brightest

young

In disc, spiral arms

Relatively high in heavier elements

In dust and gas formed from
Population II Stars

Galactic nucleus and halo

Older

Almost entirely H & He
Classification of Galaxies
Galaxy Classifications



Elliptical

practically all old stars

Some gas and dust
Normal Spiral and Barred Spiral

Various ages

Lots of gas and dust in the disk
Irregular

Mostly young bright stars, ionized gas
More Galaxies


Lenticular

Bright, flat disc

No arms

No recent stars
Dwarf


Low mass and luminosity
Active Galaxies

AGN emits lots of energy

Black hole?
Distances

Cephid variables

Standard galaxies

Tully-Fisher Relation?

21cm spectral line width

Luminosity of spiral galaxies
Galaxy Clusters



Regular

Compact, high density center

Mostly elliptical and lenticular

Many with active galaxy emition
Irregular

Our local group

Looser structure, little central density

Spirals and irregulars
Super clusters

On edges of voids
Featured Objects

Where are they

What are they

Special characteristics?

Images?