排序方式: 共有34条查询结果,搜索用时 218 毫秒
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Y. C. Joshi D. Pollacco A. Collier Cameron I. Skillen E. Simpson I. Steele R. A. Street H. C. Stempels D. J. Christian L. Hebb F. Bouchy N. P. Gibson G. Hébrard F. P. Keenan B. Loeillet J. Meaburn C. Moutou B. Smalley I. Todd R. G. West D. R. Anderson S. Bentley B. Enoch C. A. Haswell C. Hellier K. Horne J. Irwin T. A. Lister I. McDonald P. Maxted M. Mayor A. J. Norton N. Parley C. Perrier F. Pont D. Queloz R. Ryans A. M. S. Smith S. Udry P. J. Wheatley D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2009,392(4):1532-1538
We report the discovery of a 7.3 M J exoplanet WASP-14b, one of the most massive transiting exoplanets observed to date. The planet orbits the 10th-magnitude F5V star USNO-B1 11118−0262485 with a period of 2.243 752 d and orbital eccentricity e = 0.09 . A simultaneous fit of the transit light curve and radial velocity measurements yields a planetary mass of 7.3 ± 0.5 M J and a radius of 1.28 ± 0.08 R J . This leads to a mean density of about 4.6 g cm−3 making it the densest transiting exoplanets yet found at an orbital period less than 3 d. We estimate this system to be at a distance of 160 ± 20 pc. Spectral analysis of the host star reveals a temperature of 6475 ± 100 K, log g = 4.07 cm s−2 and v sin i = 4.9 ± 1.0 km s−1 , and also a high lithium abundance, log N (Li) = 2.84 ± 0.05 . The stellar density, effective temperature and rotation rate suggest an age for the system of about 0.5–1.0 Gyr. 相似文献
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A. Collier Cameron D. M. Wilson R. G. West L. Hebb X.-B. Wang S. Aigrain F. Bouchy D. J. Christian W. I. Clarkson B. Enoch M. Esposito E. Guenther C. A. Haswell G. Hébrard C. Hellier K. Horne J. Irwin S. R. Kane B. Loeillet T. A. Lister P. Maxted M. Mayor C. Moutou N. Parley D. Pollacco F. Pont D. Queloz R. Ryans I. Skillen R. A. Street S. Udry P. J. Wheatley 《Monthly notices of the Royal Astronomical Society》2007,380(3):1230-1244
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D. J. Christian D. L. Pollacco I. Skillen R. A. Street F. P. Keenan W. I. Clarkson A. Collier Cameron S. R. Kane T. A. Lister R. G. West B. Enoch A. Evans A. Fitzsimmons C. A. Haswell C. Hellier S. T. Hodgkin K. Horne J. Irwin A. J. Norton J. Osborne R. Ryans P. J. Wheatley D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2006,372(3):1117-1128
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P. A. Evans Coel Hellier Gavin Ramsay 《Monthly notices of the Royal Astronomical Society》2006,369(3):1229-1234
The intermediate polar PQ Geminorum shows a complex pulsation, caused by a spinning white dwarf, which varies markedly with wavelength. We report XMM–Newton observations, including the soft and hard X-ray bands and the first ultraviolet light curves of this star. We update the ephemeris for PQ Gem allowing us to align these data with a compilation of light curves from the optical to the X-ray. Building on work by previous authors, we show how a model in which accretion flows along skewed field lines, viewed at the correct inclination, can explain the major features of the light curves in all bands. We discuss how the skew of the field lines relates to the spinning down of the white dwarf rotation. 相似文献
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D. Pollacco I. Skillen A. Cameron D. Christian J. Irwin T. Lister R. Street R. West W. Clarkson N. Evans A. Fitzsimmons C. Haswell C. Hellier S. Hodgkin K. Horne B. Jones S. Kane F. Keenan A. Norton J. Osborne R. Ryans P. Wheatley 《Astrophysics and Space Science》2006,304(1-4):253-255
The WASP project and infrastructure supporting the SuperWASP Facility are described. As the instrument, reduction pipeline and archive system are now fully operative we expect the system to have a major impact in the discovery of bright exo-planet candidates as well in more general variable star projects. 相似文献
27.
R. A. Street D. J. Christian W. I. Clarkson A. Collier Cameron B. Enoch S. R. Kane T. A. Lister R. G. West D. M. Wilson A. Evans A. Fitzsimmons C. A. Haswell C. Hellier S. T. Hodgkin K. Horne J. Irwin F. P. Keenan A. J. Norton J. Osborne D. L. Pollacco R. Ryans I. Skillen P. J. Wheatley J. Barnes 《Monthly notices of the Royal Astronomical Society》2007,379(2):816-832
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Pollen-inferred vegetation and environmental changes in the central Tibetan Plateau since 8200 yr BP
LingYu Tang CaiMing Shen ChunHai Li JinLan Peng Hui Liu Kam-Biu Liu Carrie Morrill Jonathan T. Overpeck Julia E. Coel Bao Yang 《中国科学D辑(英文版)》2009,52(8):1104-1114
The ecotone between alpine steppe and meadow in the central Tibetan Plateau is sensitive to climate changes. Here we used
the pollen records from three lakes in this region to reconstruct the evolution of local vegetation and climate since 8200
cal. yr BP. The history of temperature and precipitation was reconstructed quantitatively with multi-bioclimatic indexes and
a transfer function from pollen records. Results show that the steppe/meadow dominated during the period of 8200–6500 cal.
yr BP, especially 8200–7200 cal. yr BP, indicating the central Tibetan Plateau was controlled by strong monsoon. The steppe
dominated during the periods of 6000–4900, 4400–3900, and 2800–2400 cal. yr BP. The steppe decreased gradually and the meadow
expanded during the period of 4900–4400 cal. yr BP. Three century-scale drought events occurred during 5800–4900, 4400–3900
and 2800 cal. yr BP, respectively. The first time when the regional climate shifted to the present level was at 6500 cal.
yr BP in the central Plateau. Since 3000 cal. yr BP, the temperature and precipitation have decreased gradually to the present
level. However, the cold climate between 700–300 cal. yr BP likely corresponds to the Little Ice Age.
Supported by Chinese Academy of Sciences 100 Talents Project (Grant No. 29082762), National Natural Science Foundation of
China (Grant Nos. 40671196, 40372085, 49371068, 49871078), and U.S. National Science Foundation (Grant Nos. ATM-9410491, ATM-008194) 相似文献
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Coel Hellier Koji Mukai & J. P. Osborne 《Monthly notices of the Royal Astronomical Society》1998,297(2):526-530
Following a recent report that AO Psc has broad iron Kα emission lines we have looked at the ASCA spectra of 15 magnetic cataclysmic variables. We find that half of the systems have Kα lines broadened by ∼ 200 eV, while the remainder have narrow lines. We argue that the Doppler effect is insufficient to explain the finding and propose that the lines originate in accretion columns on the verge of optical thickness, where Compton scattering of resonantly trapped line photons broadens the profile. We suggest that the broadening is a valuable diagnostic of conditions in the accretion column. 相似文献