Stars

Question 1

How can we find out the stellar distance

?

Answer 1

A great way to find is by parallax angle!

Question 2

What is a parallax Effect?

Answer 2

It’s an angle through which your thumb
appears to move when you switch eyes
When moving your thumb farther away, the smaller
parallax becomes.

Question 3

Steller Parallax meaning

Answer 3

The small apparent shift in position of a nearby star
relative to distant background objects due to Earth’s
orbital motion

Question 4

How is the parallax used for stars?

Answer 4

Its measure the distance from the star
(Most stars have parallax
angles of much less than
1 arc second)

Question 5

What is the size of the arc?

Answer 5

1 arc second is the size of a 10c coin at 2 km distance

Question 6

How can you find Steller in brightness/power emitted?

Answer 6

is the one seen in the sky. It is measured in apparent (visual) magnitudes.

Also, Intrinsic Brightness, or Luminosity, or Amount of light a star produces is the stellar power (energy emitted each second at all wavelengths).

Question 7

What are ways to find Steller from temperature?

Answer 7

• Cool stars (atoms are not excited out of the
ground state).
• Hot stars (atoms are excited to higher orbits
or are ionized).
Strong hydrogen Balmer lines:
• Intermediate temperature stars.

Question 8

What are spectral lines?

Answer 8

This shows the strength of the temperature in spectral lines. it even recalls the wavelengths of spectral lines tell us the chemical composition.

Question 9

How many groups are there in the Stellar spectra? What are they?

Answer 9

There is 7 and there are: 
- O 
- B
- A 
- F
- G
- K
- M
(This indicates the decreasing temperature)

Question 10

What is a way to remember the Steller spectra?

Answer 10

“Oh, Boy An F Grade, Kills Me”

Question 11

How can a steller radius size be found?

Answer 11

From the known luminosity (L) and temperature (T).

Question 12

what is the Hertzsprung–Russell (H–R) diagram/graph?

Answer 12

• is a plot of luminosity versus surface temperature

- This is an important graph in astronomy because it sorts the stars into categories by size

Question 13

Types of Stars?

Answer 13

1) Main Sequence stars
2) Red Giants and Super-giants:
3) White Dwarfs

Question 14

What is the Main Sequence Star?

Answer 14

• The hot and luminous are in the upper left
• The cool and less luminous are in the lower right
• Fuse H into He in their cores

Look at H-R diagram

Question 15

What is the Red Giants and Super-giants?

Answer 15

• Very luminous, but cold (typically 3,000- 4,000 K)
• fuse He and heavier elements in their cores

Look at H-R diagram

Question 16

What are White Dwarfs (stellar remnants)?

Answer 16

• Very dim, extremely hot (typically 20,000 K and up)

Look at H-R diagram

Question 17

What is the name for the combined Steller Mass?

Answer 17

Its called binary stars due to many stars in the sky are

in pairs

Question 18

But how is the mass determined?

Answer 18

We see periodic changes of light from binary stars.

This allows astronomers to determine their masses

Question 19

Types of Main Sequence about the Stellar-mass decreases are?

Answer 19

• The most massive MS stars are the hot and luminous stars
  (blue giants).
• The lowest-mass stars are the coolest and faintest MS stars (red dwarfs).

Question 20

How long do stars live?

Answer 20

Depends on the mass, but Massive stars have shorter lives, compared to smaller stars.

Question 21

How many stages of Evaluation Steller death are there? What are they?

Answer 21

There are 5 stages: 
Stage 1: Protostar
Stage 2: Main Sequence star
Stage 3: Red Giant
Stage 4: Planetary Nebula
Stage 5: White Dwarf

Question 22

What is stage 1?

Answer 22

Stars are born in a region of high-density Nebula and condense into a huge globule of gas and dust and contracts under its own gravity.

Question 23

What is stage 2?

Answer 23

A region of condensing matter will begin to heat up and start to glow forming Protostars. If a protostar contains enough matter the central temperature reaches 15 million degrees centigrade.

Question 24

What is stage 3?

Answer 24

The Helium core ignites for nuclear fusion into Carbon

when the core temperature exceeds 100 million K.

Question 25

What is stage 4?

Answer 25

The Red Giant gradually ejects its outer

shells forming a Planetary Nebula

Question 26

What is stage 5?

Answer 26

The core of the dying star becomes a white dwarf. Extremely hot surface (30,000 K). It would take ~25 billion yrs. for a white dwarf to cool down to a black dwarf.