cepheid stars

magnitude

• Apparent magnitude is how bright a star seems.
• Absolute magnitude is how bright a star would seem if it was 10 parsecs from earth.
• One magnitude is a ratio of brightness of 2.512, or 100 to the 1/5th power

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distance modulus

cepheid stars

• They are stars that fluctuate in their apparent magnitude. how long they take to cycle is related to their absolute magnitude. that makes them useful for determining distance.

henrietta leavitt

• Was the first person to notice the period-luminosity relationship.

light-curve

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m=-(2.76(log10(p)-1))-4.16

sources

• http://astronomy.swin.edu.au/cosmos/D/Distance+Modulus
• http://astronomy.swin.edu.au/cosmos/F/Flux
• http://www.astronomynotes.com/starprop/s4.htm
• http://astronomy.swin.edu.au/cosmos/A/Absolute+magnitude
• http://global.britannica.com/topic/magnitude-astronomy
• http://www.icq.eps.harvard.edu/MagScale.html
• http://hyperphysics.phy-astr.gsu.edu/hbase/astro/cepheid.html
• http://www.atnf.csiro.au/outreach/education/senior/astrophysics/variable_ce...