Lesson Plans: Time that Star! (Day 2)
Time That Star!
Day 2 Binary Star Data
Use the following data to perform Epoch Folding to determine the rotation period or the orbital period of the given sources.
Stellar Rotation Data
The following two data sets can tell astronomers how fast a star is rotating.
Cen X-3 Data
These data for Cen X-3 are rom EXOSAT satellite's Medium Energy experiment. All data are from 19 June 1985. The time is in seconds from the beginning of that day.
| Time (Seconds) | Rate (counts/cm2/s) |
| 0 | 14.7062277 |
| 0.484 | 14.8695928 |
| 0.968 | 15.8992848 |
| 1.452 | 15.7533336 |
| 1.936 | 16.1208738 |
| 2.42 | 15.66 |
| 2.904 | 16.5468258 |
| 3.388 | 15.211294 |
| 3.872 | 15.5961072 |
| 4.356 | 15.3717151 |
| 4.84 | 14.7062277 |
| 5.324 | 14.8695928 |
| 5.808 | 15.8992848 |
| 6.292 | 15.7533336 |
| 6.776 | 16.1208738 |
| 7.26 | 16.5247452 |
| 7.744 | 16.5468258 |
| 8.228 | 5.211294 |
| 8.712 | 5.5961072 |
| 9.196 | 15.3717151 |
GX 301-2 Stellar Rotation Data
These data for GX 301-2 are from the A2 experiment aboard the HEAO-1 satellite. All data are from 1 February 1978. The time is in seconds from the beginning of that day.
| Time (Seconds) | Rate (counts/cm2/s) | Time (Seconds) | Rate (counts/cm2/s) | Time (Seconds) | Rate (counts/cm2/s) |
| 72362.10 | 0.01388 | 73027.70 | 0.01953 | 73857.14 | 0.03258 |
| 72387.70 | 0.01512 | 73053.30 | 0.01688 | 73882.74 | 0.03518 |
| 72413.30 | 0.01593 | 73099.38 | 0.02005 | 73908.34 | 0.04642 |
| 72438.90 | 0.02347 | 73145.46 | 0.02447 | 73933.95 | 0.04945 |
| 72464.50 | 0.03103 | 73171.06 | 0.03435 | 73959.54 | 0.04190 |
| 72490.10 | 0.03113 | 73196.66 | 0.03123 | 73985.14 | 0.04512 |
| 72515.70 | 0.03387 | 73222.27 | 0.04637 | 74010.74 | 0.04933 |
| 72541.30 | 0.03270 | 73247.86 | 0.04983 | 74036.34 | 0.04593 |
| 72566.90 | 0.04195 | 73273.46 | 0.04498 | 74061.95 | 0.04435 |
| 72592.50 | 0.04873 | 73299.06 | 0.04375 | 74087.54 | 0.03997 |
| 72618.10 | 0.03942 | 73324.66 | 0.03735 | 74113.14 | 0.04358 |
| 72643.70 | 0.04453 | 73350.27 | 0.03998 | 74138.74 | 0.03462 |
| 72669.30 | 0.03557 | 73375.86 | 0.03278 | 74164.34 | 0.02330 |
| 72694.90 | 0.03318 | 73401.46 | 0.03377 | 74189.95 | 0.01715 |
| 72720.50 | 0.03347 | 73427.06 | 0.02837 | 74215.54 | 0.01945 |
| 72746.10 | 0.03520 | 73452.66 | 0.02468 | 74241.14 | 0.02760 |
| 72771.70 | 0.02420 | 73478.27 | 0.01903 | 74266.74 | 0.03603 |
| 72797.30 | 0.01890 | 73503.86 | 0.01927 | 74292.34 | 0.03190 |
| 72822.90 | 0.02057 | 73590.90 | 0.03228 | 74317.95 | 0.03705 |
| 72848.50 | 0.02873 | 73677.95 | 0.03677 | 74343.54 | 0.03342 |
| 72874.10 | 0.02737 | 73703.54 | 0.02440 | 74369.14 | 0.02537 |
| 72899.70 | 0.03315 | 73729.14 | 0.01590 | 74394.74 | 0.02307 |
| 72925.30 | 0.03692 | 73754.74 | 0.02042 | 74420.34 | 0.01768 |
| 72950.90 | 0.03377 | 73780.34 | 0.01408 | 74445.95 | 0.01930 |
| 72976.50 | 0.03375 | 73805.95 | 0.01908 | 74471.54 | 0.01730 |
| 73002.10 | 0.02500 | 73831.54 | 0.02345 |
Orbital Data
The following two data sets can tell astronomers how fast two stars are orbiting each other.
Cir X-1 Orbital Data
These data for Cir X-1 are from the RXTE Satellite's All Sky Monitor. The time is the number of days from the beginning of the mission.
| Time (Days) | Rate (counts/s) | Time (Days) | Rate (counts/s) | Time (Days) | Rate (counts/s) |
| 186.0 | 93.55 | 205.0 | 71.92 | 224.0 | 76.04 |
| 187.0 | 105.36 | 206.0 | 75.87 | 225.0 | 37.82 |
| 188.0 | 97.05 | 207.0 | 81.32 | 226.0 | 99.55 |
| 189.0 | 85.28 | 208.0 | 70.23 | 227.0 | 171.93 |
| 190.0 | 88.64 | 209.0 | 76.63 | 228.0 | 141.79 |
| 191.0 | 88.60 | 210.0 | 163.11 | 229.0 | 125.30 |
| 192.0 | 60.92 | 211.0 | 195.43 | 230.0 | 101.67 |
| 193.0 | 121.83 | 212.0 | 154.57 | 231.0 | 81.85 |
| 194.0 | 170.94 | 213.0 | 110.34 | 232.0 | 74.14 |
| 195.0 | 177.16 | 214.0 | 105.15 | 233.0 | 87.63 |
| 196.0 | 113.90 | 215.0 | 86.03 | 234.0 | 101.00 |
| 197.0 | 82.20 | 216.0 | 114.17 | 235.0 | 97.89 |
| 198.0 | 97.48 | 217.0 | 125.39 | 236.0 | 83.97 |
| 199.0 | 120.72 | 218.0 | 112.97 | 237.0 | 85.34 |
| 200.0 | 109.35 | 219.0 | 90.32 | 238.0 | 77.82 |
| 201.0 | 75.39 | 220.0 | 75.04 | 239.0 | 76.74 |
| 202.0 | 71.62 | 221.0 | 85.32 | 240.0 | 73.02 |
| 203.0 | 70.81 | 222.0 | 70.34 | 241.0 | 74.61 |
| 204.0 | 63.48 | 223.0 | 77.66 |
GX 301-2 Orbital Data
These data for GX 301-2 are from the Vela 5B satellite. The time is the number of days from the beginning of the mission.
| Time (Days) | Rate (counts/s) | Time (Days) | Rate (counts/s) |
| 41001.46 | 5.194 | 41087.55 | 4.008 |
| 41006.13 | 1.274 | 41092.22 | 0.407 |
| 41010.73 | 1.971 | 41096.88 | 0.522 |
| 41017.69 | 1.313 | 41103.66 | 0.164 |
| 41022.35 | 1.441 | 41107.27 | 0.187 |
| 41025.93 | 0.501 | 41113.02 | 0.173 |
| 41033.92 | 1.784 | 41117.71 | 0.302 |
| 41038.59 | 0.119 | 41122.36 | 10.349 |
| 41043.27 | 11.225 | 41127.03 | 1.128 |
| 41047.95 | 1.199 | 41132.80 | 0.478 |
| 41052.64 | 0.386 | 41137.50 | 0.786 |
| 41057.30 | 0.256 | 41143.28 | 1.999 |
| 41061.98 | 2.442 | 41147.95 | 1.843 |
| 41066.65 | 0.126 | 41152.64 | 1.605 |
| 41071.32 | 1.712 | 41157.27 | 0.304 |
| 41075.98 | 0.305 | 41161.96 | 5.784 |
| 41082.73 | 7.988 | 41166.64 | 5.509 |
