Third Coast最新文献

{"title":"Amplitude variability of the cepheid V473 Lyr","authors":"M. Breger","doi":"10.1553/CIA148S52","DOIUrl":"https://doi.org/10.1553/CIA148S52","url":null,"abstract":"The star V473 Lyr is a short-period cepheid (P = 1.49d) with a very strong modulation of the amplitude on a time scale near 1200d. Previously unpublished photometry is presented. This includes good coverage near the maximum amplitude. The available photometry and radial-velocity measurements going back to 1966 are analyzed with PERIOD04 to examine whether the amplitude variability is caused by beating between close frequencies. In particular, we have looked for the existence of a close frequency triplet with equidistant frequency spacing. This is required by the Combination Mode Hypothesis, which explains equidistant frequency triplets by a combination of two frequencies. The frequency triplet determined by us for V473 Lyr misses equidistancy by 0.00005 ± 0.00001 cd−1.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123616847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Future of Computational Asteroseismology","authors":"T. Metcalfe","doi":"10.1553/cia150s227","DOIUrl":"https://doi.org/10.1553/cia150s227","url":null,"abstract":"The history of stellar seismology suggests that observation and theory often take turns advancing our understanding. The recent tripling of the sample of pulsating white dwarfs generated by the Sloan Digital Sky Survey represents a giant leap on the observational side. The time is ripe for a comparable advance on the theoretical side. There are basically two ways we can improve our theoretical understanding of pulsating stars: we can improve the fundamental ingredients of the models, or we can explore the existing models in greater computational detail. For pulsating white dwarfs, much progress has recently been made on both fronts: models now exist that connect the interior structure to its complete evolutionary history, while a method of using parallel computers for global exploration of relatively simple models has also been developed. Future advances in theoretical white dwarf asteroseismology will emerge by combining these two approaches, yielding unprecedented insight into the physics of diffusion, nuclear burning, and mixing.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123293496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MOST Photometry of the roAp star HD 134214","authors":"C. Cameron, J. Matthews, J. Rowe, R. Kuschnig, D. Guenther, A. Moffat, S. Rucinski, D. Sasselov, G. Walker, W. Weiss","doi":"10.1553/cia148s57","DOIUrl":"https://doi.org/10.1553/cia148s57","url":null,"abstract":"We present 10.27 hrs of photometry of the roAp star HD 134214 obtained by the MOST 1 satellite. The star is shown to be monoperiodic and oscillating at a frequency of 2948.97 ± 0.55 μHz. This is consistent with earlier ground based photometric campaigns (e.g. Kreidl et al. 1994). We do not detect any of the additional frequencies identified in the recent spectroscopic study by Kurtz et al. (2006) down to an amplitude limit of 0.36 mmag (2σ significance limit).","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115033475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of solar-like oscillations","authors":"T. Bedding, H. Kjeldsen","doi":"10.1553/cia150s106","DOIUrl":"https://doi.org/10.1553/cia150s106","url":null,"abstract":"There has been tremendous progress in observing oscillations in solar-type stars. In a few short years we have moved from ambiguous detections to firm measurements. We briefly review the recent results, most of which have come from high-precision Doppler measurements. We also review briefly the results on giant and supergiant stars and the prospects for the future.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123670294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Period04 User Guide","authors":"P. Lenz, M. Breger","doi":"10.1553/CIA146S53","DOIUrl":"https://doi.org/10.1553/CIA146S53","url":null,"abstract":"Period04, an extended version of Period98 by Sperl (1998), is a software package designed for sophisticated time string analysis. In this article we present the User Guide for Period04.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128408074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Search for intrinsic variable stars in three open clusters: NGC 1664, NGC 6811 and NGC 7209","authors":"P. V. Cauteren, P. Lampens, C. Robertson, A. Strigachev","doi":"10.1553/CIA146S21","DOIUrl":"https://doi.org/10.1553/CIA146S21","url":null,"abstract":"We report on new time-series CCD observations for three poorly studied open clusters from the STACC list. The collected light curves in the V lter of a large number of stars per eld have been examined in detail in search for shortperiodic variable stars. In particular we looked for new Scuti-type candidates. First results for the open clusters NGC 1664, NGC 6811 and NGC 7209 are presented.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126753152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-degree non-radial modes in the δ Scuti star AV Ceti","authors":"L. Mantegazza, E. Poretti","doi":"10.1553/CIA146S33","DOIUrl":"https://doi.org/10.1553/CIA146S33","url":null,"abstract":"High-resolution spectroscopic observations taken during 5 consecutive nights of the fast rotating δ Scuti star AV Ceti (v sin i = 188km/s) show the presence of non-radial modes with ` ∼ 10 − 16 and very short periods (ν ∼ 40− 70 c/d) Introduction and Observations The rapidly rotating δ Scuti star AV Ceti has been recently the target of a simultaneous photometric and low-resolution spectroscopic international campaign (Dall et al. 2003). Seven low-degree modes were detected in the frequency range 10-31 c/d. We observed this star with the Coudé Echelle Spectrograph attached at the ESO CAT Telescope during 5 consecutive nights (October 24-30, 1994; Remote Control from Garching headquarters) for about 2.5 consecutive hours per night and 55 spectrograms were collected with exposure times of 10 min and a typical S/N ratio at the continuum level of about 230. They had a resolution of 60000 and cover the region 4494-4513 Å. In this region we have two useful lines to study line profile variations: TiII 4501Å and FeII 4508Å. Fig. 1 shows the average continuum normalized spectrum (upper panel) and the pixel-by-pixel standard deviation (lower panel). Added by editor (MB): The Astronomy and Astrophysics publisher used an incorrect name for the star (AV Cetei instead of AV Ceti) in the title and running head of the Dall et al. paper. The authors of the present publication note: Cetus,-i belongs to the second latin declination (as, for example, Cepheus,-i) : nominative and genitive cases are different (Cephei, Ceti). On the other hand, Doradus,-us belongs to the fourth declination and the genitive is the same as the nominative (γ Doradus, not γ Doradi). For a correct use of abbreviations of constellations see http://www.iau.org/Activities/nomenclature/const.html 34 High-degree non-radial modes in the δ Scuti star AV Ceti Figure 1: Average normalized spectrum (top panel); pixel-by-pixel data standard deviation (lower panel). Data analysis and discussion We can see that the line profiles have variations with a std.dev of about 0.002 of the continuum level. A non-linear least-squares fit of a rotationally broadened Gaussian intrinsic profile, taking also into account the limb darkening, on the two average line profiles supplies v sin i = 188± 1 km/s. The line profile variations were analyzed by means of the Fourier Doppler Imaging Technique (Kennelly et al. 1998; Hao 1998). Fig. 2 shows the twodimensional power spectrum obtained considering all the data in a single time series and merging the information of the two spectral lines. We see that there is a clear clump of modes in the region 10 ≤ ` ≤ 16, 35 ≤ ν ≤ 70 c/d. Because of the very severe aliasing, due to the poor temporal coverage, it is not possible to derive a detection of individual modes. A CLEANed version of this power spectrum is shown in Fig. 3 (gain=0.9, 100 iterations). This figure should be considered only as indicative, and the individual modes cannot be taken at face value, since the poor spectra","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124340784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Note on the short-period variability of V521 Cas in NGC 7789","authors":"P. V. Cauteren, P. Lampens, A. Pigulski","doi":"10.1553/CIA144S23","DOIUrl":"https://doi.org/10.1553/CIA144S23","url":null,"abstract":"Recent observations of V521 Cas in the open cluster NGC7789 do not conflrm that the star is a ‐ Scuti variable (within the observational limits).","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115677382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulsating stars in open clusters","authors":"T. Arentoft, L. Freyhammer, M. Bouzid, C. Sterken, S. Frandsen","doi":"10.1553/CIA145S65","DOIUrl":"https://doi.org/10.1553/CIA145S65","url":null,"abstract":"We report studies that are carried out with the aim of searching for and studying short-period variable stars in northern open clusters. The background for these studies is described along with the results that have been obtained up to now.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130209164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SZ Lyn: New BVRI CCD observations and improved pulsational and orbital elements","authors":"K. Gazeas, P. Niarchos, K. Boutsia","doi":"10.1553/cia144s26","DOIUrl":"https://doi.org/10.1553/cia144s26","url":null,"abstract":"New BVRI CCD observations of the pulsating star SZ Lyn are presented. The light curves are analyzed using Fourier transform techniques and a new period is determined. A new ephemeris, based on recent times of maxima, is proposed. The photometric data collected over the last 40 years are used to determine the pulsational and orbital elements, since SZ Lyncis is a member of a binary system. The results are compared with those found in previous studies.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116453615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}