Search

Your search keyword '"Coates, D"' showing total 1,324 results
Start Over Author "Coates, D"
1,324 results on '"Coates, D"'

19. Aperture Photometry of Saturated Star Images from Digitised Photographic Plates

Author

Innis, J. L., Coates, D. W., Borisova, A. P., and Tsvetkov, M. K.

Subjects
Astrophysics
Abstract

Saturated stellar images on digitised photographic plates are many times greater in area than the `seeing disk' seen in unsaturated CCD images. Indeed the flux profile of a bright star can be traced out for several degrees from the star's centre. The radius of the saturated stellar image can often be directly related to the magnitude of the star, a fact well known and exploited in iris photometry. In this work we compare the radial flux profile of stars in the approximate range B ~9 to ~13 mag, obtained from scans of plates from the Bamberg Sky Patrol archive, with a profile of the form measured by King. We show that simple aperture photometry of saturated stellar images, obtained from photo-positives of scanned photographic plates, yield data that are in agreement with simulations using a (saturated) synthetic stellar radius profile. Raw plate magnitudes from this aperture photometry can be easily and satisfactorily transformed to standard magnitudes, as demonstrated in a recent study carried out by the current authors., Comment: 11 pages, 6 figures

Published
2005

21. Archival light curves from the Bamberg Sky Patrol - CFOctantis, 1964-1976

Author

Innis, J. L., Borisova, A. P., Coates, D. W., and Tsvetkov, M. K.

Subjects
Astrophysics
Abstract

We use the archive of the Bamberg Sky Patrol to obtain light curves of the active K subgiant CF Octantis for the interval 1964-1976. Digitised images of the field near CF Oct were obtained with a flat-bed scanner. Aperture photometry was performed of photo-positives of these images. Using a transformation to second order in plate magnitude, and first order in B-V, for 9 field stars for each plate, the B magnitudes of CF Octantis were obtained for just over 350 plates. The estimated precision of an individual determination of the B magnitude of CF Oct is 0.05 mag. Analysis of the resulting data reveals the known 20 d rotational variation of this star, and shows the evolution of the light curves from year to year. We obtain light curves with good phase coverage for 1964 to 1969 inclusive, partial light curves for 1970 and 1976, and a few data points from 1971. The amplitude of variation ranges from ~0.2 to \~0.4 mag. There is evidence that the characteristic rotation period of the star in the 1960s was slightly less than that measured from photoelectric photometry in the 1980s., Comment: 11 pages, 11 figures, accepted for publication in MNRAS

Published
2004
Full Text
View/download PDF

40. Evaluating conservation strategies for the endangered daisy Schoenia filifolia subsp. subulifolia (Asteraceae): fitness consequences of genetic rescue and hybridisation with a widespread subspecies

Author

Monks, L., Coates, D., McArthur, S., Standish, R.J., Monks, L., Coates, D., McArthur, S., and Standish, R.J.

Abstract

Context: To establish translocated populations of threatened plants with the genetic resources to adapt to changing environmental conditions, the source of propagation material is an important consideration. Aim: We investigated the fitness consequences of genetic rescue and admixture for the threatened annual daisy Schoenia filifolia subsp. subulifolia, and the common S. filifolia subsp. filifolia, to inform seed-sourcing strategies for translocations of the threatened subspecies. Methods: We evaluated genetic diversity of two populations of S. filifolia subsp. subulifolia and four populations of S. filifolia subsp. filifolia by using microsatellite markers. We grew seedlings from each study population and cross-pollinated inflorescences within and among populations of the same subspecies, and between subspecies. We evaluated the fitness consequences of each cross by using seed set, seed weight and seed viability. Key results: There was a lower genetic diversity in the small (<50 plants, Nar = 3.28, He = 0.42) compared to the large (>10 000 plants, Nar = 4.42, He = 0.51) population of S. filifolia subsp. subulifolia, although none of the measures was significantly different, and seed fitness was slightly, although not significantly, reduced in interpopulation crosses compared with the small population. Genetic diversity was similar between the threatened and widespread subspecies; however, the subspecies were genetically divergent (Fst = 0.242–0.294) and cross-pollination between subspecies produced negligible amounts of seeds (<3% seed set). Conclusions: Although genetic rescue or admixture of S. filifolia subsp. subulifolia would not necessarily result in greatly increased levels of genetic diversity or seed fitness, we still consider it a potential option. Negligible seed set in crosses between subspecies indicates that deliberate hybridisation is not a possibility. Implications: Studies of fitness consequences of admixture or genetic rescue are rare yet critica

Published
2022

42. Starspot lifetimes from long-term photometry

Author

Anders, G. J., Coates, D. W., Thompson, K., Innis, J. L., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Byrne, Patrick B., editor, and Mullan, Dermott J., editor

Published
1992
Full Text
View/download PDF

45. Response to letter to the editor

Author

Dadich, A, Piper, A, and Coates, D

Subjects
Health Policy & Services, 08 Information and Computing Sciences, 11 Medical and Health Sciences
Published
2021

Catalog

Books, media, physical & digital resources
See catalog results