SCI10 - 2nd LE

Module 3 and 4

massive; luminous

The first stars were _____ and _____ that their formation lead to the production and dispersion of heavier elements which lead to the formation of the ______ today.

Density fluctuation

____ left over from the big bang could have evolved into the first stars.

Distant quasars

Observations of ______ allowed scientists to catch a glimpse of the final days of the cosmic dark ages.

Quasars (Quasi-stellar radio sources)

• luminous and for celestial objects in the universe that are detected due to the large electromagnetic radiation that they emit

• They are thought to be powered by supermassive black holes at the centers of galaxies

Protogalaxies

Star-forming system is much smaller and less organized than the modern galaxy

Protogalaxies

Does not contain significant amounts of any elements besides hydrogen and helium

Protogalaxies

merge to form galaxies and would gather into galaxy clusters

Jean mass

minimum mass that a clump of a gas must have to collapse under its gravity

Formation of Protogalaxies

• Clouds of gas and dust that slowly aggregates to form more matter

• As they evolve, they will begin to merge with each other and form larger structures like the galaxy that we know today

Nebuli

(1) Stars are formed from a cloud of dust and hydrogen gas called ___.

Protostar

The life of a star begins as a _____.

Protostar

Hot core formed from the collection of a dust and gas.

Accretion

Growing of protostar by adsorbing more material from its surroundings.

increase

Accretion results in the ___ of temperature and density.

Thermonuclear fusion

(2) Hydrogen molecules in these clouds begin to react with one another to form Helium gas through the process _____.

hot ball of gas

(3) With enough mass and huge amount of energy the protostar eventually collapses into its own gravitational force and forms a _____

1. Re-ionization

2. Chemical enrichment

3. Galactic evolution

What are the roles of the first stars in the formation of later stars and planets?

Re-ionization

This is one of the roles of the 1st stars in the formation of later stars and planets where there is the emission of ultraviolet radiation, ionizing surrounding hydrogen gas in the universe.

Chemical enrichment

This is one of the roles of the 1st stars in the formation of later stars and planets. This allowed for the formation of later generations of stars (Population I and II), which could form smaller stars, planets, and complex molecules necessary for life.

Galastic evolution

This is one of the roles of the 1st stars in the formation of later stars and planets. The presence of metals made it possible for subsequent generations of stars to form planets and other structures more easily.

• Surface temperature

• Luminosity

Classification of Stars

• Microphysics

• Macrophysics

Categories for Stars Formation

Microphysics

Category for star formation that deals with how individual stars form.

Macrophysics

Category of star formation that deals with how systems of stars form, ranging from clusters to galaxies

• Less massive stars

• Massive stars

• Most massive stars

Lifespan of Stars (3)

Less massive stars

Lifespan of stars: Emit their stellar material into space that will leave behind a white dwarf surrounded by a planetary nebula.

Massive stars

Lifespan of star: Blast matter in the solar space in a bright supernova that leaves behind a highly dense body called a nuetron star

Most massive stars

Lifespan of stars: (3x the mass of the sun) collapse into themselves and creates black holes.

Life Cycle of a Star

• a star

• 8 planets

• countless smaller bodies (dwarf planets, asteroids and comets)

Our solar system is made up of _____

• Mercury

• Venus

• earth

• Mars

• Jupiter

• Saturn

• Uranus

• Neptune

Enumerate the order of the planets in the solar system, starting nearest the sun and working outward.

How did our solar system come about?

1. Protoplanetary disk formation

2. Dust grain growth

3. Planetesimals formation

4. Protoplanetary cores

5. Terrestrial planet formation

6. Clearing the disk

7. Stabilizing and Evolution

8. Mature Planetary System

Planetary Formation

Protoplanetary disk formation

Planetary formation which contains the rotating disk of gas and dust

Dust grain growth

Planetary formation where dust growth collide and stick together due to Van der Waals forces forming larger particles

Planetesimals formation

Planetary formation where larger dust aggregates accumulate and form larger objects; continues to grow through collisions and gravitational interaction.

Protoplanetary cores

Planetary formations where massive planetesimals attract significant amount of gas from the protoplanetary disk; building blocks of gas giants planets.

Terrestrial planet formation

Planetary formation where planetesimals collide and merge in the inner regions of planetary disk; closer to the sun

Clearing the disk

Planetary formation where protoplanets interact with surrounding gas which either accrete more materials or clear out their paths

Stabilization and Evolution

Planetary formation where planets stabilize in their orbits, and the protoplanetary disk gradually dissipates.

Mature Planetary System

Planetary formation where protoplanetary disk is gone and planets are in stable orbits around the sun.

How planets form?

Small objects in space coalesce and form planet precursors called Planetesimals —> Planetesimals gather together due to common gravity and form a planet.

Terrestrial planets

• Made of rocky material

• solid surface

• no ring systems

• few moons

• relatively small

Mercury

• known as a shrinking planet because its iron core is slowly cooling causing it to affect the planet’s overall size to decrease

• does not contain an atmosphere, just a thin layer of exosphere

Maxwell Montes

Volcano in Venus that is almost as high as Mt. Everest

Sulfuric Acid (H₂SO₄)

The rain in Venus is made up of _____

It reflects 70% of all the sunlight that reaches the planet

Cause of Venus’ brightness

Earth

• only planet known to sustain life

• Because of its distance from the sun, it is able to contain water in all of its form

• Life on earth first began in the oceans in the form of microorganisms

Mars

• THE RED PLANET

• same seasons as the Earth but these seasons lasts longer

• Gravity is weaker compared to earth

• atmosphere is mostly composed of CO₂

Jupiter

• Solar system’s first planet largest planet in the solar system contains 79 moons

• THE GREAT RED SPOT

  • the most iconic feature of Jupiter

  • A crimson brown storm raging for 300 years

  • a giant collection of swirling clouds

Saturn

• lightest planet

• Less dense than water

• largest storm is located on its north pole and has a hexagonal shape.

Saturn’s Ring System

• 7 layers

• composed of icy remnants of comets, asteroids, and moons

• it stays on track and intact due to Saturn’s smallest moons which orbits between the rings and uses their gravity to shape it.

Uranus

• coldest planet

• rotates vertically along its equator

• contains 13 rings and 27 moons

Its surface is made up of water, ammonia, methane

What is the cause of the planet’s blue color?

Neptune

• cold, dark and icy due to its far distance from the sun

• contains 6 rings and 14 moons

Triton

What is Neptune’s largest moon?

Jovian Planets

Pluto

“DWARF PLANET”

Structure

• Core

• Mantle

• Crust

= contains 5 moons

Its inability to clear its orbit of debris was the cause why Pluto lost its status as a planet

Why is Pluto not a planet?

1. Orbit the Sun

2. Not a moon

3. Enough mass to be round

4. Able to clear orbit of debris

4 Characteristics of a Planet

Nucleosynthesis

• It is the process of forming a new atomic nuclei from existing smaller nuclei.

• An atomic nuclei may be formed through the combination of light elements or from the breakdown of heavier elements

Nuclear fusion

a combination of two or more atomic nuclei to form one or more new atomic nuclei

Nuclear fission

breakdown of a nuclei into two or more separate nuclei

• Big-bang Nucleosynthesis

• Stellar Nucleosynthesis

• Supernova Nucleosynthesis

Types of Nuleosynthesis

Big-bang Nucleosynthesis

• Lighter elements (H and He, traces of Li, Be, B) formed

• 3 minutes - 300,000 years after Bigbang

Stellar Nucleosynthesis

• elements (some He to Fe) synthesized in young stars through fusion

• Extreme temperature is required at the core

Supernova Nucleosynthesis

• Heavier elements formed during supernova explosions of stars

• conditions: extremely high temp (100 billion degrees C) and abundant neutrons

Atom

Basic unit of an element that can enter into chemical reaction

Contains a nucleus that is composed of a proton and a neutron that is surrounded by electrons.

• Proton

• Electron

• Neutron

Structure of an Atom

Atomic number (Z)

number of protons

Mass number (A)

number of protons + number of neutrons

atomic number + number of neutrons

equal

All atoms may be identified from the number of protons and neutrons they contain. In a neutral atom, the number of protons is ____to the number of electrons. The chemical identity of an atom may be determined from its atomic number alone.

Isotopes

• atoms of the same number of atomic number (Z) but different mass numbers (A)

Radioactivity

• a phenomenon when an unstable nuclei emit particles and/or electromagnetic radiation spontaneously.

• Any element that spontaneously emits radiation is said to be radioactive

• Three rays are emitted by radioactive elements

  • Alpha ray

  • Beta

  • Gamma

Alpha ray

consists of positively charged particles called a - particles

Beta ray

B-particles are electrons

Gamma (Y) rays

high energy rays that does not have a charge

Familiarize these radioactive elements

Nuclear Stability

• The figure shows a plot of the number of proton vs. number of neutrons of different isotopes

Belt of stability (solid line)

A stable nuclei is found on the area of the graph

Radioactive isotopes; radioactive decay

_____ are found outside this belt. In order to obtain stability, these isotopes must undergo _____.

Above the belt of stability; beta-dacay

(1)There is a higher neutron-to-proton ratio. In order to reach the belt of stability, they need to lower this ratio by undergoing (2) ______.

(1) Below belt of stability; (2) either through positron emission or electron capture

(1) There is a lower neutron-to-proton ratio. In order to reach the belt of stability, they need to move upward by increasing this ratio _____.

Heavy nuclei (atomic numbers (Z) > 83)

(1) _____ are naturally radioactive and are found above the belt of stability. In order to reach the belt of stability, they would need to undergo ____ in order to decrease both the number of protons and neutrons.

• Alpha decay (or emission)

• Beta (B) decay

• Positron emission

• Gamma (y) decay

• Electron capture

Types of radioactive decay

Alpha decay (emission)

A Helium or nucleus is emitted

Beta (B) decay

an electron is emitted

Positron emission

a positron, is emitted when an atom decays to produce a neutron and a positron

Gamma (Y) decay

high energy photons or gamma rays are emitted

Electron capture

an electron falls into the nucleus and fuses with a proton to form a neutron