Stars Flashcards
(26 cards)
How can we find out the stellar distance
?
A great way to find is by parallax angle!
What is a parallax Effect?
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.
Steller Parallax meaning
The small apparent shift in position of a nearby star
relative to distant background objects due to Earth’s
orbital motion
How is the parallax used for stars?
Its measure the distance from the star
(Most stars have parallax
angles of much less than
1 arc second)
What is the size of the arc?
1 arc second is the size of a 10c coin at 2 km distance
How can you find Steller in brightness/power emitted?
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).
What are ways to find Steller from temperature?
• 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.
What are spectral lines?
This shows the strength of the temperature in spectral lines. it even recalls the wavelengths of spectral lines tell us the chemical composition.
How many groups are there in the Stellar spectra? What are they?
There is 7 and there are: - O - B - A - F - G - K - M (This indicates the decreasing temperature)
What is a way to remember the Steller spectra?
“Oh, Boy An F Grade, Kills Me”
How can a steller radius size be found?
From the known luminosity (L) and temperature (T).
what is the Hertzsprung–Russell (H–R) diagram/graph?
- is a plot of luminosity versus surface temperature
- This is an important graph in astronomy because it sorts the stars into categories by size
Types of Stars?
1) Main Sequence stars
2) Red Giants and Super-giants:
3) White Dwarfs
What is the Main Sequence Star?
- 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
What is the Red Giants and Super-giants?
- Very luminous, but cold (typically 3,000- 4,000 K)
- fuse He and heavier elements in their cores
Look at H-R diagram
What are White Dwarfs (stellar remnants)?
• Very dim, extremely hot (typically 20,000 K and up)
Look at H-R diagram
What is the name for the combined Steller Mass?
Its called binary stars due to many stars in the sky are
in pairs
But how is the mass determined?
We see periodic changes of light from binary stars.
This allows astronomers to determine their masses
Types of Main Sequence about the Stellar-mass decreases are?
- 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).
How long do stars live?
Depends on the mass, but Massive stars have shorter lives, compared to smaller stars.
How many stages of Evaluation Steller death are there? What are they?
There are 5 stages: Stage 1: Protostar Stage 2: Main Sequence star Stage 3: Red Giant Stage 4: Planetary Nebula Stage 5: White Dwarf
What is stage 1?
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.
What is stage 2?
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.
What is stage 3?
The Helium core ignites for nuclear fusion into Carbon
when the core temperature exceeds 100 million K.
