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Orbital motion of substellar companions

Orbital motion of substellar companions. Christian Ginski , Ralph Neuhäuser, Markus Mugrauer , Tobias Schmidt AIU Jena. „ Brown Dwarfs come of Age “ 22th May 2013. Background Image Credit : ESO/L. Calcada. Motivation.

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Orbital motion of substellar companions

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  1. Orbital motion of substellar companions Christian Ginski, Ralph Neuhäuser, Markus Mugrauer, Tobias Schmidt AIU Jena „Brown Dwarfs come of Age“ 22th May 2013 Background Image Credit:ESO/L. Calcada

  2. Motivation C. Ginski 2013 May 22th

  3. DetectionMethods

  4. DetectionMethods

  5. DetectionMethods

  6. DetectionMethods

  7. DetectionMethods Jupiter Saturn Neptune Uranus

  8. DetectionMethods young old

  9. DetectionMethods – Direct Imaging Confirmationof Companion Candidates: Multiple images in different observing epochs can be taken to confirm that the companion candidate is co-moving with the primary star. Photometry and spectra can be taken to confirm that the object is low-mass and of a similar age as the primary star. Problems: Observation campaigns target young associations in which all members exhibit similar proper motion Associationmembersexhibitsimilarage Detectionof orbital motionwouldsolvetheseproblems, i.e. wouldfinallyconfirmcompanionship + studyoforbitparametersmightgiveinsightto planet andbrowndwarfformation + determinationoftheorbitallowsdynamiccalculationofthe total systemmass

  10. ObservingEpochs and AstrometricMeasurements C. Ginski 2013 May 22th

  11. Observations – HD130948 VLT – NaCo NB 2.17 Caha 3.5m – ALFA: Ω-CASS H-Band N H-Band E N E Gemini North – Hokupa‘a/QUIRC Potter et al. 2002 Dupuy & Liu 2011: 0.1095 ± 0.0022 Mʘ

  12. Observations – GSC 08047 Neuhäuser et al. 2003 NTT – SHARPI N 2 arcsec E VLT – NaCo Ks-Band N E

  13. Observations Very Large Telescope, Chile Calar Alto Observatory, Spain

  14. Archive Data – HD130948 Gemini – NIRI Subaru – IRCS HST – ACS CH4 (short) H-Band F850 LP Gemini – Hokupa‘a/QuIRC H-Band N N N N E E E E

  15. Astrometric Calibration Binaries Cluster 47 Tuc VLT – NaCo Ks-Band HIP 73357 N E

  16. AstrometricResults – HD130948 VLT – NaCo NB 2.17 N E

  17. AstrometricResults – HD130948 N E

  18. AstrometricResults – HD130948 2.2 ± 3.7 mas/yr

  19. AstrometricResults – HD130948 0.16 ± 0.07 deg/yr

  20. AstrometricResults – GSC08047 6.3 ± 0.9 mas/yr

  21. AstrometricResults – GSC08047

  22. Orbit Fitting C. Ginski 2013 May 22th

  23. Least-Squares Monte-Carlo Method Implemented in Python SciPy (E. Jones, T. Oliphant , P. Peterson et al. 2001) - open-source software for mathematics, science, and engineering NumPy (D. Ascher et al. 1999) - fundamental package for scientific computing with Python Matplotlib (J. Hunter et al. 2007) - python 2D plotting library which produces publication quality figures

  24. Results - HD130948 Hill stabilitycriterionasgiven in Donnison et al. 2010

  25. Results - HD130948

  26. Results - HD130948

  27. Results - HD130948

  28. Results - HD130948

  29. Results - HD130948

  30. Results - GSC08047

  31. Results - GSC08047

  32. Conclusions C. Ginski 2013 May 22th

  33. Conclusions • Common proper motioncouldbeconfirmedforbothpresentedcompanions • orbital motion was detected but noorbitcurvatureyet • thedetectedorbitmotionisconsistentwithlowmassobjects on wideorbits • high eccentricitieswould fit scatterscenarios Astrometric Calibration of future measurements is vital for orbit determination !

  34. Further Work Small orbitcurvature was detected in thecaseofthe PZ Tel systemandtheorbitcouldbeconstrainedwellwiththe LSMC method. The system was not discussedherebecausethestudyisledby Dr. Markus Mugrauer. P = 110 yr Mugrauer, Röll, Ginski et al. 2012

  35. Thanksforyourattention !

  36. Additional Information

  37. LSMC vs MCMC

  38. Absolute Orbits GQ Lupby Neuhäuser et al. 2008 HD203030 byMetchev et al. 2006 CT Chaby Schmidt et al. 2008

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