Question

1. what is the spectral type (letter and number) of the following stars. use this unlv website: physics.unlv.edu/~jeffery/astro/star/star_brightest.html

sun________ vega______ sirius a________
betelgeuse________ alpha centauri a______ aldebaran________
which star from above has the hottest surface temperature?____________________
which star from above has the coolest surface temperature?____________________
what do you think the approximate colors of the listed stars would be?
sun__________________ vega________________ sirius__________________
betelgeuse__________________ alpha centauri a________________ aldebaran__________________

Explanation:

Step1: Access the website

Go to physics.unlv.edu/~jeffery/astro/star/star_brightest.html to find spectral - type information.

Step2: Identify spectral types

• Sun: G2V
• Vega: A0V
• Sirius A: A1V
• Betelgeuse: M2Ia - ab
• Alpha Centauri A: G2V
• Aldebaran: K5III

Step3: Determine hottest star

Based on the spectral - type sequence (OBAFGKM, with O being the hottest and M the coolest), Vega and Sirius A are A - type stars which are hotter than the others. Among them, Vega (A0V) has a higher surface temperature than Sirius A (A1V). So the hottest is Vega.

Step4: Determine coolest star

Betelgeuse and Aldebaran are M and K - type stars. Among them, Betelgeuse (M2Ia - ab) is cooler than Aldebaran (K5III). So the coolest is Betelgeuse.

Step5: Determine star colors

• Sun: Yellow (G - type)
• Vega: White (A - type)
• Sirius: White (A - type)
• Betelgeuse: Red (M - type)
• Alpha Centauri A: Yellow (G - type)
• Aldebaran: Orange - red (K - type)

Answer:

Sun: G2V, Yellow
Vega: A0V, White
Sirius A: A1V, White
Betelgeuse: M2Ia - ab, Red
Alpha Centauri A: G2V, Yellow
Aldebaran: K5III, Orange - red
Hottest surface temperature: Vega
Coolest surface temperature: Betelgeuse