{"title":"Probing the amplitude modulation and pulsational energy re-distribution in the oscillation of HD 137949","authors":"C.N. Ofodum , P.N. Okeke , B.I. Okere","doi":"10.1016/j.newast.2023.102176","DOIUrl":null,"url":null,"abstract":"<div><p><span>We present the result of over 50-h of Johnson-B photometric observation of HD 137949. These high-speed photometric data were acquired between June 12 and August 19 2013 using the 0.5-m telescope of the South African Astronomical Observatory (SAAO). The result of our frequency analysis when compared with that of similar B-light photometric data obtained in 1981 and 1987 using the same telescope reveals the existence of a long-term stability in its principal frequency of oscillation at </span><span><math><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>.</mo><mn>014781</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>000003</mn></mrow></math></span> mHz; even with the excitation of two new secondary oscillations (<span><math><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>.</mo><mn>016787</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>000006</mn></mrow></math></span> mHz; <span><math><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>=</mo><mn>2</mn><mo>.</mo><mn>012628</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>000009</mn></mrow></math></span> mHz). On the contrary, the signature of its principal amplitude of oscillation (<span><math><mi>A</mi></math></span>) was found to have changed drastically within a time-span of about three decades. However, the aggregate amplitude (<span><math><mrow><mo>∑</mo><mi>A</mi></mrow></math></span>) of all the detected oscillations was observed to have remained constant within the period under investigation. In addition, HD 137949 was observed to have undergone pulsational energy re-distribution within this time-span of about three decades; with a signature that is suggestive of non-conservation of its total energy (pulsational). We discuss the possible implications of the recently observed dynamics in the oscillation-signature of HD 137949.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Astronomy","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S138410762300177X","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
We present the result of over 50-h of Johnson-B photometric observation of HD 137949. These high-speed photometric data were acquired between June 12 and August 19 2013 using the 0.5-m telescope of the South African Astronomical Observatory (SAAO). The result of our frequency analysis when compared with that of similar B-light photometric data obtained in 1981 and 1987 using the same telescope reveals the existence of a long-term stability in its principal frequency of oscillation at mHz; even with the excitation of two new secondary oscillations ( mHz; mHz). On the contrary, the signature of its principal amplitude of oscillation () was found to have changed drastically within a time-span of about three decades. However, the aggregate amplitude () of all the detected oscillations was observed to have remained constant within the period under investigation. In addition, HD 137949 was observed to have undergone pulsational energy re-distribution within this time-span of about three decades; with a signature that is suggestive of non-conservation of its total energy (pulsational). We discuss the possible implications of the recently observed dynamics in the oscillation-signature of HD 137949.
期刊介绍:
New Astronomy publishes articles in all fields of astronomy and astrophysics, with a particular focus on computational astronomy: mathematical and astronomy techniques and methodology, simulations, modelling and numerical results and computational techniques in instrumentation.
New Astronomy includes full length research articles and review articles. The journal covers solar, stellar, galactic and extragalactic astronomy and astrophysics. It reports on original research in all wavelength bands, ranging from radio to gamma-ray.