Four OB stars and a new massive early-B binary system were identified by detecting their infrared bowshock nebulae using data from the Wide Field Infrared Survey Explorer. Spectroscopic observations of the stars were conducted using the Wyoming Infrared Observatory 2.3 meter telescope. Spectral analysis revealed that the stars have spectral types of B1V, B2V, B5V, and B0V, and one system is a short-period binary. The identification of these massive runaway stars helps evaluate stellar mass loss and improve models of OB star evolution. Future work includes continued searches for more runaway stars and closer analysis of their properties.

1. Identifying Massive Runaway Stars by Detecting Infrared Bowshock
Nebula: Four OB Stars and a New Massive Early-B Binary System
R. L. Sorber4,2, J. E. Andrews1,2, M. S. Povich1, H. A. Kobulnicky2, W. T. Chick2, D. A. Dale2, S. Munari2, G. M. Olivier3,2, D.
Schurhammer2, H. N. Wernke5,2
1Department of Physics and Astronomy, Cal Poly Pomona, 2 University of Wyoming, 3 Case Western Reserve University, 4 Front Range Community College, 5 Embry-Riddle Aeronautical
University
B1V
G092.3191 + 0.0591
Binary System
B2V
G086.55104 -1.083935
G075.5711 -0.2558
B0V
G076.69921 -2.4071
B5V
Introduction
• OB type star main sequence
evolution is well understood
• Mass loss for these stars are
highly uncertain
• Some massive OB stars are ejected
from birth site by gravitational
encounters
• Traveling at 30 km/s creating
Bowshock Nebulae
Methods
• Visual inspection of Wide Field Infrared Survey
Explorer (WISE)
• Identified candidates using low Galactic
latitudes in 22-micron images.
• Each candidate was observed using Wyoming
Infrared Observatory (WIRO) 2.3 meter telescope.
• Each star was observed on 3 different nights using
longslit spectrograph averaging 3 - 6 exposures
at 300s - 600s each.
• CCD camera was calibrated after eachexposure using
CuAr spectra and flats and bias to eliminate defects.
Results
• G086.6083 – Observed on 2015 July 3, 10, 27, 28
• Spectral analysis indicates this star is a B2V type star and a
strong hydrogen line.
• Shifting helium line from right to left 15 km/s indicates a possible
short-period binary star system.
• G076.6921 – Observed on 2015 June 23, 10, 23, & July 28,
& Aug 29.
• Spectral analysis shows a B5V type star. This slightly noisy
spectra shows a hydrogen & helium I and possibly helium II line.
• G092.3191 – Observed on 2015 June 21, 22, 23 & July 12
• Spectral analysis shows B1V type star and a well defined helium I
line.
• G075.5711 – Observed on 2015 July 3, 10, 11
• Spectral analysis shows a B0V type star and a well developed
helium I line.
Conclusion
• Enlarged the database of massive runaway stars hosting
bowshocks.
• Provided promising samples for evaluating stellar mass
loss to accurately predict end of life evolution as a
neutron star, a black hole, or a supernova.
• Reconciling theoretical and actual values to provide an
opportunity to develop a better OB star model life cycle.
• Gives a better understanding of the circumstances that
exist in star forming nebula through out our galaxy.
Future Opportunities
• Continued search for Massive Runaway Stars in the Milky Way Galaxy
• Closer evaluation of star vital statistics for future comparison
• Identify, confirm and assess early-B binary star system for gravitational
interactions and evolution.
Acknowledgements
This work is supported by the National Science Foundation Grants AST-1063146 (REU),
AST-1411851 (RUI), and AST-1412845.
References:
Photo: Panorama Milky Way, eso.org
Kobulnicky et al., 2010. ApJ, 710, 549K
Figure 1,2,3,4 - images of bowshock stars red is WISE 22
microns, green is WISE 12 microns, blue is WISE 3.4 microns
Figure 5 – Panorama Milky Way with red dots as bowshock candidates
Figure 6 - CuAr calibration spectrum
Figure 7 – G092.3191 spectral analysis for star typing using SPTassist
Figure 6
Figure 7
Figure 5
Figure 4
Figure 3
Figure 2
Figure 1