Astronomy Chapter 10 – Flashcards

The nearest star system to our Sun, Alpha Centauri, is still over a parsec distant. T/F

The stars with masses comparable to our Sun's, but sizes like the Earth are A. blue main sequence stars. B. white dwarfs. C. red main sequence stars. D. neutron stars. E. red giants.

The mass of a newly formed star will determine its position on the main sequence. T/F

A star's absolute magnitude is its apparent brightness as seen from A. Alpha Centauri. B. 10 light-years distance. C. 10 parsecs distance. D. 100 parsecs distance. E. Pluto.

What can be said with certainty about a red star and a blue star? A. The blue star has a greater proper motion than the red star. B. The red star is more massive than the blue star. C. The red star has a greater radial velocity than the blue star. D. The blue star is hotter than the red star. E. The red star is closer to Earth than the blue star.

Which statement about stellar motion is incorrect? A. Radial velocity is measured by the Doppler shifts of the spectral lines. B. The closer stars usually show larger proper motions. C. The space velocity can be found from the radial and transverse velocities. D. You must also know the parallax to get the transverse velocity. E. Proper motion is measured in intervals of six months.

Molecular lines, such as TiO, are only found in very hot stars. T/F

On the H-R diagram, red supergiants like Betelgeuse lie A. at the bottom left. B. at the bottom right. C. at the top right. D. at the top left. E. They can't be plotted, for they are not main sequence.

If Vega is apparent magnitude zero, and Deneb first magnitude, then A. Vega is about 100× brighter than Deneb. B. Vega is 2.5× brighter than Deneb. C. Deneb must be a main sequence star, and Vega a giant. D. Deneb is one magnitude brighter than Vega. E. Vega must be 2.5× hotter than Deneb.

How much brighter will a 4th magnitude star appear than a 6th magnitude star? A. 2.5 times B. 16 times C. 2.0 times D. 8 times E. 6.25 times

In what range of masses are most stars found? A. Stars can have any mass. B. 0.1 to 100 solar masses C. 1 to 3 solar masses D. 0.1 to 2 solar masses E. 0.01 to 100 solar masses

On the H-R diagram, the Sun lies A. about the middle of the main sequence. B. at the top right. C. at the bottom right. D. at the bottom left. E. at the top left.

Which type of binary can have their sizes measured directly by photometry? A. virtual B. astrometric C. eclipsing D. visual E. spectroscopic

What physical property of a star does the spectral type measure? A. density B. mass C. composition D. luminosity E. temperature

Of all the stars in the sky, Barnard's star, the next closest beyond Alpha Centauri, appears to move the fastest. T/F

The H-R diagram can plot A. radius versus mass. B. temperature versus mass. C. radius versus luminosity. D. apparent magnitude versus spectral classes. E. temperature versus luminosity.

Fewer than 100 stars lie within 5 parsecs of the Sun. T/F

Most stars are single stars like our own. T/F

The parallactic angle is the total shift observed over a six-month interval. T/F

A star is 10 parsecs from Earth. Which statement is true? A. The star's apparent magnitude is larger than its absolute magnitude. B. The star is in a different galaxy. C. The star's apparent magnitude is smaller than its absolute magnitude. D. The star's parallax is 1.0 arc seconds. E. The star is about 33 ly away.

Which of these stars would be the hottest? A. M10 B. K9 C. B0 D. A0 E. G2

Compared to the size of the Sun, stars of all types range from A. 0.001 to 50,000 solar radii. B. 0.5 to 50 solar radii. C. 0.01 to 1,000 solar radii. D. 0.1 to 10 solar radii. E. 0.08 to 8,000 solar radii.

The Doppler shift is used to find A. visual binaries. B. spectroscopic binaries. C. eclipsing binaries. D. astrometric binaries. E. photometric binaries.

The stars α Cygni and β Cygni are in the constellation Cygnus. Which statement is true? A. α Cygni appears brighter. B. β Cygni appears brighter. C. β appears redder. D. β is hotter. E. α must be the eastern most star in the constellation.

The Sun, at absolute magnitude +4.8, would be one of the brightest stars in the sky if seen from 32 light-years distance. T/F