Is this project an undergraduate, graduate, or faculty project?
Undergraduate
Project Type
group
Campus
Daytona Beach
Authors' Class Standing
Benjamin Katz, Sophmore
Lead Presenter's Name
Benjamin Katz
Lead Presenter's College
DB College of Arts and Sciences
Faculty Mentor Name
Dr. Jason Aufdenberg
Abstract
Broad Emission-Line Limits on Stellar Winds from Small-Aperture DSLR Spectroscopy Wolf-Rayet (WR) stars have very strong stellar winds, with speeds of thousands of km/s, usually measured using high-resolution spectroscopy on large telescopes. Here, we test how well those speeds can be recovered using small-aperture, low-resolution DSLR spectroscopy. We used an 8-inch Celestron 8SE with an SA-100 grating and a Nikon D750 DSLR, giving a dispersion of about 4.1 Å per pixel. A key limitation is the instrumental resolution of the system, with an FWHM of about 30 Å, which is not small compared to the emission line widths being measured. We observed WR 140 and WR 6, stacking 63x15 s exposures (945 s total) for WR 140 and 27x20 s exposures (540 s total) for WR 6, and reduced the data using RSpec and AstroImageJ. FWHM values were measured for strong emission lines and corrected for instrumental broadening to estimate wind speeds. For WR 140, FWHM values of about 69-80 Å give wind speeds between ~3100-4500 km/s with uncertainties of ~150-215 km/s, compared to published values near 2800-3000 km/s. For WR 6, measured speeds range from ~1800 to ~2800 km/s depending on the line, while the published value is about 1700 km/s. In both cases, the results are in the correct range but often too high, likely due to line blending and limited resolution. Overall, DSLR-based, small-aperture spectroscopy can recover the correct order of magnitude for stellar wind speeds, but instrumental effects dominate and introduce a systematic bias toward higher velocities.
Did this research project receive funding support (Spark, SURF, Research Abroad, Student Internal Grants, Collaborative, Climbing, or Ignite Grants) from the Office of Undergraduate Research?
No
Included in
Instrumentation Commons, Physical Processes Commons, Stars, Interstellar Medium and the Galaxy Commons
Broad Emission-Line Limits on Stellar Winds from Small-Aperture DSLR Spectroscopy
Broad Emission-Line Limits on Stellar Winds from Small-Aperture DSLR Spectroscopy Wolf-Rayet (WR) stars have very strong stellar winds, with speeds of thousands of km/s, usually measured using high-resolution spectroscopy on large telescopes. Here, we test how well those speeds can be recovered using small-aperture, low-resolution DSLR spectroscopy. We used an 8-inch Celestron 8SE with an SA-100 grating and a Nikon D750 DSLR, giving a dispersion of about 4.1 Å per pixel. A key limitation is the instrumental resolution of the system, with an FWHM of about 30 Å, which is not small compared to the emission line widths being measured. We observed WR 140 and WR 6, stacking 63x15 s exposures (945 s total) for WR 140 and 27x20 s exposures (540 s total) for WR 6, and reduced the data using RSpec and AstroImageJ. FWHM values were measured for strong emission lines and corrected for instrumental broadening to estimate wind speeds. For WR 140, FWHM values of about 69-80 Å give wind speeds between ~3100-4500 km/s with uncertainties of ~150-215 km/s, compared to published values near 2800-3000 km/s. For WR 6, measured speeds range from ~1800 to ~2800 km/s depending on the line, while the published value is about 1700 km/s. In both cases, the results are in the correct range but often too high, likely due to line blending and limited resolution. Overall, DSLR-based, small-aperture spectroscopy can recover the correct order of magnitude for stellar wind speeds, but instrumental effects dominate and introduce a systematic bias toward higher velocities.