Observation by Kevin Gurney: Metallic A-type star
Uploaded by
Kevin Gurney
Observer
Kevin Gurney
Observed
2018 Mar 21 - 01:03
Uploaded
2018 Mar 23 - 18:48
Objects
Spectrum
Equipment
- Altair Astro 10in RC truss tube
- Alpy 600 Spectrograph
- Mesu 200 mount
- Atik 460EX
Exposure
12 x 120sec sub-exposures
Location
West Sheffield
Target name
HD 93901
Title
Metallic A-type star
About this image
HD 93901 is an Am-type star - that is, class A, but with strong metallicity (I love the way astrophysics can't count beyond 3 , and calls anything other than H or He, a 'metal' :). This is manifest in the spectrum by the increased amplitude of features between the Balmer lines. The full spectrum is given as kA4hA7mF5 (which gives relative stengths of the k -line, H, and metallicity, m).
The top panel of the figure shows the (instrument-corrected) spectrum in red, and a 'standard' A-type star for comparison (HD103478, A3V, taken on the same night). Below, are the rectified spectra (continuum removed) where I have also scaled the Am-type star to have the same amplitude range as its standard counterpart, and shifted it up slightly to ease comparison. [Is the general increase in amplitude of the A3V star a luminance effect? I couldnt see a luminance given in the spectrum...].
I still remain astounded at how much you can see from your backyard with a low-res spectroscope... :)
Files associated with this observation
Like this image
Copyright of all images and other observations submitted to the BAA remains with the owner of the work.
Reproduction of work by third parties is expressly forbidden without the consent of the copyright
holder. By submitting images to this online gallery, you grant the BAA permission to reproduce them in
any
of our publications.