The Appearance and Disappearance of Exocomet Gas Absorption
CaII K-line (3933 Å) absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (...
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Wiley
2015-01-01
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| Series: | Advances in Astronomy |
| Online Access: | http://dx.doi.org/10.1155/2015/980323 |
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| author | Barry Y. Welsh Sharon L. Montgomery |
| author_facet | Barry Y. Welsh Sharon L. Montgomery |
| author_sort | Barry Y. Welsh |
| collection | DOAJ |
| description | CaII K-line (3933 Å) absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (HD 58647) and four new A-type (HD 56537, HD 64145, HD 108767, and HD 109573) stellar systems exhibit short-term (night-to-night) absorption variation within these profiles. This variability is due to the liberation of gas from falling evaporating bodies (the so-called FEBs activity) on the grazing approach of exocomets towards their parent star. Also we present archival spectra of the FeI λ3860 Å and CaII K-lines towards β Pictoris (HD 39060) that, for the first time, reveal the absorption signatures of FEB activity at similar velocities in both line profiles. FEB-hosting stars seem to be of an earlier type (on average spectral type Al.8 as compared with A3.1) than those where no FEB activity has been observed. This could be due to stellar activity levels (such as chromospheric activity or nonradial pulsations) being of a higher level within the atmospheres of these hotter A-type stars. |
| format | Article |
| id | doaj-art-e61315e1375f47f089c442d34f7b45a7 |
| institution | Kabale University |
| issn | 1687-7969 1687-7977 |
| language | English |
| publishDate | 2015-01-01 |
| publisher | Wiley |
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| series | Advances in Astronomy |
| spelling | doaj-art-e61315e1375f47f089c442d34f7b45a72025-02-03T05:51:23ZengWileyAdvances in Astronomy1687-79691687-79772015-01-01201510.1155/2015/980323980323The Appearance and Disappearance of Exocomet Gas AbsorptionBarry Y. Welsh0Sharon L. Montgomery1Experimental Astrophysics Group, Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720, USADepartment of Chemistry, Mathematics & Physics, Clarion University, Clarion, PA 16214, USACaII K-line (3933 Å) absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (HD 58647) and four new A-type (HD 56537, HD 64145, HD 108767, and HD 109573) stellar systems exhibit short-term (night-to-night) absorption variation within these profiles. This variability is due to the liberation of gas from falling evaporating bodies (the so-called FEBs activity) on the grazing approach of exocomets towards their parent star. Also we present archival spectra of the FeI λ3860 Å and CaII K-lines towards β Pictoris (HD 39060) that, for the first time, reveal the absorption signatures of FEB activity at similar velocities in both line profiles. FEB-hosting stars seem to be of an earlier type (on average spectral type Al.8 as compared with A3.1) than those where no FEB activity has been observed. This could be due to stellar activity levels (such as chromospheric activity or nonradial pulsations) being of a higher level within the atmospheres of these hotter A-type stars.http://dx.doi.org/10.1155/2015/980323 |
| spellingShingle | Barry Y. Welsh Sharon L. Montgomery The Appearance and Disappearance of Exocomet Gas Absorption Advances in Astronomy |
| title | The Appearance and Disappearance of Exocomet Gas Absorption |
| title_full | The Appearance and Disappearance of Exocomet Gas Absorption |
| title_fullStr | The Appearance and Disappearance of Exocomet Gas Absorption |
| title_full_unstemmed | The Appearance and Disappearance of Exocomet Gas Absorption |
| title_short | The Appearance and Disappearance of Exocomet Gas Absorption |
| title_sort | appearance and disappearance of exocomet gas absorption |
| url | http://dx.doi.org/10.1155/2015/980323 |
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