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Catching Up In Auriga

Catching Up In Auriga. new variable stars and how to find them- Stan Waterman. Summary facts: Auriga data. Data collected from 25/10/2003 to 30/3/2008 This during 76 nights In between Cygnus work of higher priority 25,000 images, 21,000 pass quality tests

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Catching Up In Auriga

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  1. Catching Up In Auriga new variable stars and how to find them- Stan Waterman BAA VSS Oct 14th 2011

  2. Summary facts: Auriga data • Data collected from 25/10/2003 to 30/3/2008 • This during 76 nights • In between Cygnus work of higher priority • 25,000 images, 21,000 pass quality tests • Longest night 11-1/2/2006- 12 hrs 31mins • Start at el=45.6° to 79.9° and down to 16.7° BAA VSS Oct 14th 2011

  3. Location in Auriga 05 18 +41 50 capella BAA VSS Oct 14th 2011

  4. BAA VSS Oct 14th 2011

  5. History so far • Started October 2000 - first two years gaining experience • 66,400 quality-filtered images since Aug 2003 in main Cygnus area (area ‘a’) • But also some data in 8 contiguous areas in Cygnus (10,000)- Each 2.8 degrees square, 7.84 sq. Degrees • Plus 25,000 in Auriga (total area 86 sq. degrees) • The area ‘a’ has more than 220,000 measurable stars • 17,000 of those have 5 year light curves • 1022 variable stars found in area ‘a’ so far BAA VSS Oct 14th 2011

  6. Outline and Summary • Outline of data pipeline • Ways of finding variable stars with examples • So far (11/10/11) I’ve found 178 • 63 eclipsing binaries, 64 slow variables • 37 fast variables, 1 Cepheid, 13 misc • Six of those are in the GCVS BAA VSS Oct 14th 2011

  7. Data Pipeline, part 1 • Collect data- 1 image every 46seconds • Rename files- Fits convert-extract time info • Convert to APL, x10, dark subtraction, flat division • Find brightest 6,000 stars, quality assessment, log data -vimp • Calculate picture coefficients (144 stars, 4th order poly, 16 coefficients) • Probe images at starlist ra, dec positions* (60,000 or 28,000) • Collect pixel sets for each star, add to previous and store- singlesets • Collect average sets, 2401 per image, 20 images averaged • *Probing by ra and dec allows us to make average sets centred at fixed ra/dec and also to observe any large-enough proper motions. BAA VSS Oct 14th 2011

  8. Data Pipeline-part 2 • Store Fits and processed images • Probe pixel-sets to create diameter sets • Each star is measured at in 14 diameters • 3x3 pix and 4 to 16 diameter • Noise is measured in quiet dates and optimum diameter evaluated • Each star is then ratioed to each of 10 local comparison stars BAA VSS Oct 14th 2011

  9. Data Pipeline- part 3 • At this point a number of obvious variable stars pop out • So, re-evaluate the star ratios • Repeat a few times • End result: good light curves for all stars with several comparison stars for each BAA VSS Oct 14th 2011

  10. Light Curves • For the Auriga data these are 20,086 x14 magnitude values from 76 dates • From a nominal 28,738 stars • 8.08 billion data values • Explain nominal! BAA VSS Oct 14th 2011

  11. Finding the Variables • Fast noise • Slow noise • Scattery noise • Spiky noise • Overlay analysis • Fourier Analysis • Star colour hints BAA VSS Oct 14th 2011

  12. Fast Noise (one night) This is the image to image variation 735 data points- rms 14.5 mmag BAA VSS Oct 14th 2011

  13. Fast NoiseThis is the image to image variation 735 data points BAA VSS Oct 14th 2011

  14. Elevation range that night BAA VSS Oct 14th 2011

  15. 10 point block average SD 15.8mmag BAA VSS Oct 14th 2011

  16. 10 point block average SD 3.1 mmag BAA VSS Oct 14th 2011

  17. Examples Mag 13.8 not var Mag 13.8 var Mag 15.4 var BAA VSS Oct 14th 2011

  18. Samples of Noise (mmag) v Diam In mmags diameter star BAA VSS Oct 14th 2011

  19. Star 380 in date 2593 BAA VSS Oct 14th 2011

  20. Iso and Prox Star 380 101 pixels square star 418 BAA VSS Oct 14th 2011

  21. Slow Noise 2003/4 2005/6 2006/7 2007/8 Each of 76 dots is the average of one night The rms variation over those 1619 days is 12mmag BAA VSS Oct 14th 2011

  22. Star 380 again BAA VSS Oct 14th 2011

  23. Star p00380 4yr phase plot BAA VSS Oct 14th 2011

  24. GCVS stars in the area GCVS Variable Stars in Stan’s Auriga Area Star Type m P (d) Sp. myid SX Aur EB 8.38-9.14 1.2100855 B3 V+ B5 V 41 SY Aur DCEP 8.74-9.40 10.14465 F5-F8 61 ER Aur DCEP 11.17-11.80 15.6973 742 V414 Aur Be 8.20-8.30 B2 Vne 27 V425 Aur EB 7.62-7.90 1.568583 B5 12 V489 Aur LB: 12.5-13.3 876 BAA VSS Oct 14th 2011

  25. SX Aur EB 8.38-9.14 1.2100855 BAA VSS Oct 14th 2011

  26. SY AurigaDCEP 8.74-9.40 10.14465 My range is 0.519- gcvs is 0.66 BAA VSS Oct 14th 2011

  27. ER Aur DCEP 15.6973 Range 0.46mag---- gcvs is 0.63 mag BAA VSS Oct 14th 2011

  28. Slow Noise- long period variables -LPVs BAA VSS Oct 14th 2011

  29. Slow Noise- LPVs and SRs 64 found so far 35 0.260 632 0.190 STARE 1697 0.390 4006 0.460 47 0.590 iras 665 0.180 STARE 1843 0.330 4048 0.470 141 0.210 761 0.130 2107 0.250 4055 0.150 184 0.086 825 0.130 2174 0.590 4761 0.660 CGCS 206 0.450 iras 876 0.870 2253 0.000 8016 0.660 258 0.041 963 0.420 2292 0.960 8402 0.290 264 0.612 1021 0.600 2309 0.250 8463 0.460 356 0.250 STARE 1154 0.380 CGCS 2366 0.440 CGCS 8904 0.600 382 0.166 1165 0.170 2381 0.570 10812 0.800 384 0.250 STARE 1217 0.420 2533 0.250 11404 0.180 409 0.500 1239 0.110 2541 1.340 CGCS 13694 0.650 459 0.122 1311 0.240 STARE 2585 0.120 15009 0.920 495 0.810 1318 0.760 STARE 2686 0.410 15268 1.030 536 0.312 1389 0.250 STARE 2855 0.410 19924 0.850 548 0.280 1421 0.150 STARE 3362 0.500 22947 0.930 588 0.270 STARE 1490 0.180 3775 0.000 26863 0.500 CGCS BAA VSS Oct 14th 2011

  30. LPVs and SRs graded in variabiliy 2541 1.340 CGCS 47 0.590 iras 1154 0.380 CGCS 665 0.180 STARE 15268 1.030 2174 0.590 1843 0.330 1490 0.180 2292 0.960 2381 0.570 536 0.312 11404 0.180 22947 0.930 409 0.500 8402 0.290 1165 0.170 15009 0.920 3362 0.500 548 0.280 382 0.166 876 0.870 26863 0.500 CGCS 588 0.270 STARE 1421 0.150 STARE 19924 0.850 4048 0.470 35 0.260 4055 0.150 495 0.810 4006 0.460 356 0.250 STARE 761 0.130 10812 0.800 8463 0.460 384 0.250 STARE 825 0.130 1318 0.760 STARE 206 0.450 iras 1389 0.250 STARE 459 0.122 4761 0.660 CGCS 2366 0.440 CGCS 2107 0.250 2585 0.120 8016 0.660 963 0.420 2309 0.250 1239 0.110 13694 0.650 1217 0.420 2533 0.250 184 0.086 264 0.612 2686 0.410 1311 0.240 STARE 258 0.041 1021 0.600 2855 0.410 141 0.210 2253 0.000 8904 0.600 1697 0.390 632 0.190 STARE 3775 0.000 BAA VSS Oct 14th 2011

  31. Biggest mover- but only 1.3mag Carbon star CGCS 878 BAA VSS Oct 14th 2011

  32. Faintest one BAA VSS Oct 14th 2011

  33. Slow Red Variables in Cygnus area ‘a’ Star id magr starid magr 11459 5.3 16783 5 1055 3.47 V407 6077 1.81 V575? 14833 1.81 955 1.72 V573 12001 1.69 11293 1.58 2086 1.37 V362 4851 1.32 3403 1.29 18915 1.28 17886 1.25 11496 1.11 2550 1.07 BAA VSS Oct 14th 2011

  34. Finding the Variables • Fast noise • Slow noise • Scattery noise • Spiky noise -------- • Overlay analysis • Fourier Analysis • Star colour hints BAA VSS Oct 14th 2011

  35. Spiky Ones BAA VSS Oct 14th 2011

  36. Star p00057- 45mmag BAA VSS Oct 14th 2011

  37. Star p00303- eccentric (Ød =0.35) 4 years data BAA VSS Oct 14th 2011

  38. Star p02147- detached eb 4 years data BAA VSS Oct 14th 2011

  39. Star p03046 4 years data BAA VSS Oct 14th 2011

  40. BAA VSS Oct 14th 2011

  41. Overlay Scans-Periodograms BAA VSS Oct 14th 2011

  42. BAA VSS Oct 14th 2011

  43. SX Aur 1.210090 BAA VSS Oct 14th 2011

  44. List of eclipsing stars so far star period star period star period star

  45. Fourier Searching • Good at the fast ones • Only one long night needed • But three is better • I used 2170 2202 and 2211 which are • 10/12/2005 and 11/1, 20/1 2006 • 11.8 12.5 and 11.6hrs long • Longest: el=45.6° to 79.9° down to 16.7° • It’s very quick – 28,000 stars in 40mins BAA VSS Oct 14th 2011

  46. Fourier Searching First, I tried looking at those where 6th or higher harmonic dominated: 867 6 0 0 12 0 0 7 5 0 14 13 0 6 5 0 13 12 0 1 0 1864 6 0 0 7 0 0 10 0 0 7 0 0 0 0 0 0 0 0 1 0 yes 3678 6 0 0 6 0 0 0 0 0 0 0 0 15 7 0 2 4 0 0 1 5323 5 0 0 6 0 0 5 0 0 4 0 0 14 5 0 2 4 0 0 1 5507 9 6 0 8 9 0 10 0 0 12 0 0 10 0 0 10 0 0 0 1 8990 5 0 0 11 0 0 9 5 0 3 2 0 0 0 0 0 0 0 0 0 9911 19 7 0 6 5 0 12 7 0 6 7 0 16 0 0 6 0 0 1 0 yes 11503 5 0 0 7 0 0 0 0 0 0 0 0 5 0 0 4 0 0 1 0 yes 37 found so far- incomplete BAA VSS Oct 14th 2011

  47. Fourier Searching Auto scan criterion: peak> 5 times 90%rms BAA VSS Oct 14th 2011

  48. Fourier plot of Star p09911 BAA VSS Oct 14th 2011

  49. Star p01864- 11.0932 cycles/day amplitude 29mmags BAA VSS Oct 14th 2011

  50. BAA VSS Oct 14th 2011

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