1 / 16

The Nature of Herbig Ae/Be Companion Stars

The Nature of Herbig Ae/Be Companion Stars. A 2005 CTIO REU Project by: Ben Brandvig With Advisors: Bernadette Rodgers Nicole van der Bliek Sandrine Thomas. Herbig Ae/Be Stars. Intermediate mass Pre-main-sequence Emission lines Usually a circumstellar disk & associated NIR excess

christoffer-carus
Download Presentation

The Nature of Herbig Ae/Be Companion Stars

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 Nature of Herbig Ae/Be Companion Stars A 2005 CTIO REU Project by: Ben Brandvig With Advisors: Bernadette Rodgers Nicole van der Bliek Sandrine Thomas

  2. Herbig Ae/Be Stars • Intermediate mass • Pre-main-sequence • Emission lines • Usually a circumstellar disk & associated NIR excess • High binary frequency (Testi, Leinert) • Spectral types have been previously determined

  3. Companions to Herbig Ae/Be Stars • Less massive than the Herbig primaries • With the same age as the primaries (PMS), assumed to be T Tauris • May lack the NIR excess normally associated with T Tauris (Bouvier & Corporon (2001)) • Spectral types are not well known

  4. Goals • Determine spectral type of companions • Determine binarity • Observe whether the companions are lacking the expected NIR excess • Learn more about PMS evolution in the vicinity of a higher mass star

  5. Data Sources

  6. HR5999/ V856 Sco Hen 3-225/ HD76534 MWC166 MWC863 Gu CMa V586 Ori BF Ori MWC 147 The Sample (so far)

  7. Spectral Energy Distributions (SEDs)

  8. SED Limitations • Distance and extinction to these systems is not well known • Fitting to the visual component of the SED may not be strictly correct • Pre-main-sequence stars change in radius as they move towards the ZAMS • Spectral type can only be estimated to within several subclasses

  9. The Next Step: Spectra • Photometry only provides a preliminary guess of the companion’s spectral type • With analysis of resolved spectra, the spectral types are determined accurately • The determined spectral type can be combined with the SED to estimate distance and look for NIR excess • Spectra for only one star from our sample, Hen 3-225, has been obtained thus far.

  10. Hen 3-225 - Photometry • Primary fits a B3 profile within the given distance and extinction range • Companion’s spectral type is not easily determined from the SED

  11. Hen 3-225 - Spectra • Telluric standard (A0V) has deep H absorption features

  12. Hen 3-225 – Spectra • Primary appears to resemble a B3e • H absorption in companion is considerably less than in the telluric (an A0V star) • He I lines in the companion point to a spectral type earlier than A0V, rather than later • Companion shows no strong emission features…not PMS?

  13. Hen 3-225 • Distance constraint has been removed

  14. Hen 3-225 – Conclusion • H absorption and He I lines point to a spectral type significantly earlier than A0V • SED profile is easily fit to an early B star when the distance constraint is removed • SED and spectra support an early B star with no excess/emission • Luminosity difference between components suggests the companion is a background star at ~1000pc

  15. What Remains to Be Done… • More spectral analysis for Hen 3-225 • Correct model photospheres for radius • Similar spectral/SED analysis for all sample stars • Expand sample with more resolved photometry and spectra?

  16. Thanks to… • My wonderful advisors! • Jerome Bouvier • The CTIO & Gemini staff

More Related