1 / 23

The 2011 Periastron Passage of the Bebinary  Sco

The 2011 Periastron Passage of the Bebinary  Sco. Anatoly Miroshnichenko University of North Carolina at Greensboro USA. Parameters of the  Sco Binary The Primary’s Disk During the Last Orbital Cycle Current Status and Predictions for the Periastron. Parameters of  Sco.

cili
Download Presentation

The 2011 Periastron Passage of the Bebinary  Sco

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The 2011 Periastron Passage of the Bebinary Sco Anatoly Miroshnichenko University of North Carolina at Greensboro USA • Parameters of the  Sco Binary • The Primary’s Disk During the Last Orbital Cycle • Current Status and Predictions for the Periastron

  2. Parameters of  Sco Optical brightness without disk, V=2.32 mag Spectral type B0.3 IV Distance, D = 12315 pc Luminosity, log L/Lʘ = 4.40.1 Surface temperature, Teff = 27500500 K Surface gravity, log g = 4.0 (typical of a dwarf) This is a binary system with an angular separation at apoastron of 0.2 arcseconds Orbital period, P = 10.8 years Eccentricity, e = 0.940.01 Secondary, V ~1.7 mag, Sp.T. ~B3 (uncertain)

  3. Scoin the HRD

  4. Orbit of Sco Angular Separation: Apoastron – 200 mas Periastron – 6 mas Interferometric data from 1970’s to 1990’s  Sco A

  5.  Sco without Disk

  6. When did the Emission Appear? Koubsky 2005, Astrophys. & Space Science, 296, 165

  7. Orbit of  Sco Average radial velocities of the H emission line near periastron in 2000 4 months Add 10.8 years

  8. Brightness  Spectrum

  9. Disk in 2001

  10. Disk in 2001 From Carciofi et al. (2006, ApJ, 652, 1617)

  11. Recent Brightness Variations

  12. Current State Data from Sebastian Otero as of 5/5/2011

  13. H Line Width Drop

  14. Possible Explanations The brightness decrease in 2004/5 can be due to a decreasing mass loss from the primary The disk became a ring Observed consequences: The H line width decreased (no contribution from rapidly rotating part of the disk) The line equivalent width (EW) decreased

  15. What to Expect at Periastron The primary’s disk size was ~ 20 R1 or ~ 150 Rʘ Distance between the stars at periastron is d = 24 R1 Primary’s Roche lobe size ~ 0.6 d or ~ 15 R1 Consequences: Some disk material may flow into the secondary’s Roche lobe Disk may become denser and line emission will rise Single- or triple-peak profiles may be observed

  16. Roche Lobes

  17. H line in 2000 and 2010/11

  18. What to Observe • He II 4686 Ǻ to trace the photospheric radial velocity • H to trace the entire disk changes • He I 5876 and 6678 Ǻ to trace changes in the inner parts of the disk • Very high signal-to-noise spectra of the HeI 4471 + Mg II 4481 Ǻ to try to detect the secondary • Spectra need accompanying photometry • Interferometry will further constrain the orbit

  19. Secondary’s Signature at Periastron Radial velocity difference is ~120 km/s

  20. He II 4686 Ǻ Region OII OII NIII OII

  21. Disk Before Periastron

  22. Disk At Periastron

  23. Disk After Periastron

More Related