Who used the radial pulse of Cepheid star to measure the distance of the star from Earth?
Leavitt
Why are there two dips in the Lightcurve in each period?
During eclipses of either star, two sharp dips are observed in the light curve. The dips in brightness are caused by the combined areas during the eclipse or occultation, producing decreasing the total brightness. Periods of all EA types averages about 10 days, or more.
What is the most accurate way to determine the distance to a relatively nearby galaxy?
Astronomers estimate the distance of nearby objects in space by using a method called stellar parallax, or trigonometric parallax. Simply put, they measure a star’s apparent movement against the background of more distant stars as Earth revolves around the sun.
What property of a Cepheid variable can you determine if you know its period?
All Cepheids with a certain period are assumed to have the same absolute magnitude. Measuring the apparent magnitude of a Cepheid then allows us to determine its distance using the period-luminosity relationship. If two Cepheids have the same period but is fainter than the other it must be further away.
What property of a Cepheid variable can you determine if you know its period quizlet?
What property of a Cepheid variable can you determine if you know its period? emission nebulae.
Are variable stars on the main sequence?
These stars of spectral type A or occasionally F0, a sub-class of δ Scuti variables found on the main sequence. They have extremely rapid variations with periods of a few minutes and amplitudes of a few thousandths of a magnitude.
Is spectroscopic parallax accurate?
In practice this technique is not very precise in determining the distance to an individual star. Uncertainties in the absolute magnitude of stars of specific spectral and luminosity class range from about 0.7 up to 1.25 magnitudes. These then give a factor of 1.4 to 1.8 × variation in the resultant distance.
What is the cause of stellar parallax?
What is the cause of stellar parallax? the gradual motion of stars in the local solar neighborhood. the gradual change in the patterns of the constellations over thousands of years. Earth’s orbit around the Sun.
Which of the following would allow stellar parallax to be measured more accurately?
Statistical parallax The motion of the Sun through space provides a longer baseline that will increase the accuracy of parallax measurements, known as secular parallax. For stars in the Milky Way disk, this corresponds to a mean baseline of 4 AU per year, whereas for halo stars the baseline is 40 AU per year.
Which star has the greatest luminosity and which appear the brightest?
Regulus appears the faintest in our sky. We know this because its apparent magnitude is the largest (most positive). Which star has the greatest luminosity? Antares has the greatest luminosity because its absolute magnitude is the smallest.
Which star is closest to our solar system after the sun )?
Alpha Centauri A