1:45 PM - 3:15 PM
[O08-P64] Spectroscopic Observation of Meteor Showers Using Diffraction Gratings
Keywords:Spectroscopic Observation, Meteor
1 Background and Objectives
This research started when I noticed that the color of meteors changed during the course of the meteor shower when I photographed meteors with a DSLR camera. The objectives of this study are twofold: "to identify the elements (meteoric material and Earth's atmosphere) related to meteor emission by ground-based spectroscopic observations" and "to investigate the trends in the elements contained in each meteor shower.
2-1 Observation method
First, a spectrograph made by myself using a brazed grating is attached to a digital SLR camera. Next, during the active period of the meteor shower, the camera is set up so that the meteors appear vertically in relation to the camera's angle of view, and continuous photography is performed.
2-2 Analysis method
First, the light of the elements with known wavelengths is incident at the same position as the meteors in the spectral image, and the diffraction grating scale is obtained. Then, the wavelength of each emission line is determined from the interval of emission lines on the image using the image analysis software "Makali`i". Finally, the elements originating from the luminescence are deduced.
The spectral images of meteors taken in the past are collected for each meteor shower, and the results are tabulated to discuss the trend of each meteor shower.
3 Results and Discussion
We have taken about 688,000 images so far, and obtained 66 spectral images of meteors.
The most meteors in the Geminids were photographed.
The results show that Nal is less abundant than MgI, especially in the 2017 Geminids. The reason for the difference is considered to be related to the high volatility of Na, the orbital period of the parent body, and the distance between the perihelion and the parent body.
The new spectral images obtained last year showed a similar trend to that of 2017. This has increased the certainty of the previous discussion.
In the previous study (*2), Na was significantly deficient in the Geminids, but in our ground-based observations, Na was not as deficient as in the previous study.
4 Future issues and prospects
In the future, we would like to improve the observation method, take spectroscopic images of more meteors, and clarify the trends of the constituent elements in other groups. We would like to re-calibrate the spectroscopic images of meteors we have been able to take so far, and clarify the trend of meteor showers based on the intensity of light rather than the number of images.
References
*1 National Astronomical Observatory of Japan (2014): "Rika Nenpyo Heisei 27-nen," Maruzen Publishing Co.
*2 A 2004 Geminid meteor spectrum in the visible-ultraviolet region Extreme Na depletion? (T. Kasuga, J.Watanabe, and N.Ebizuka) A&A
This research started when I noticed that the color of meteors changed during the course of the meteor shower when I photographed meteors with a DSLR camera. The objectives of this study are twofold: "to identify the elements (meteoric material and Earth's atmosphere) related to meteor emission by ground-based spectroscopic observations" and "to investigate the trends in the elements contained in each meteor shower.
2-1 Observation method
First, a spectrograph made by myself using a brazed grating is attached to a digital SLR camera. Next, during the active period of the meteor shower, the camera is set up so that the meteors appear vertically in relation to the camera's angle of view, and continuous photography is performed.
2-2 Analysis method
First, the light of the elements with known wavelengths is incident at the same position as the meteors in the spectral image, and the diffraction grating scale is obtained. Then, the wavelength of each emission line is determined from the interval of emission lines on the image using the image analysis software "Makali`i". Finally, the elements originating from the luminescence are deduced.
The spectral images of meteors taken in the past are collected for each meteor shower, and the results are tabulated to discuss the trend of each meteor shower.
3 Results and Discussion
We have taken about 688,000 images so far, and obtained 66 spectral images of meteors.
The most meteors in the Geminids were photographed.
The results show that Nal is less abundant than MgI, especially in the 2017 Geminids. The reason for the difference is considered to be related to the high volatility of Na, the orbital period of the parent body, and the distance between the perihelion and the parent body.
The new spectral images obtained last year showed a similar trend to that of 2017. This has increased the certainty of the previous discussion.
In the previous study (*2), Na was significantly deficient in the Geminids, but in our ground-based observations, Na was not as deficient as in the previous study.
4 Future issues and prospects
In the future, we would like to improve the observation method, take spectroscopic images of more meteors, and clarify the trends of the constituent elements in other groups. We would like to re-calibrate the spectroscopic images of meteors we have been able to take so far, and clarify the trend of meteor showers based on the intensity of light rather than the number of images.
References
*1 National Astronomical Observatory of Japan (2014): "Rika Nenpyo Heisei 27-nen," Maruzen Publishing Co.
*2 A 2004 Geminid meteor spectrum in the visible-ultraviolet region Extreme Na depletion? (T. Kasuga, J.Watanabe, and N.Ebizuka) A&A