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Article
Two families of exocomets in the β Pictoris system
Statistical analysis of over a thousand spectra of the star β Pictoris reveals that it has two kinds of exocomets circling it: old exhausted comets trapped in mean-motion resonance with a massive planet, and f...
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Article
The origin of hydrogen around HD 209458b
Arising from: M. Holmström et al. Nature 451, 970–972 (2008)10.1038/nature06600; Holmström et al. reply
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Article
An extended upper atmosphere around the extrasolar planet HD209458b
The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed1,2. Together with radial velocity measurements3, this has led to a determination of the pl...
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Article
Deficiency of molecular hydrogen in the disk of β Pictoris
Molecular hydrogen (H2) is by far the most abundant material from which stars, protoplanetary disks and giant planets form, but it is difficult to detect directly. Infrared emission lines from H2 have recently be...
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Article
A high deuterium abundance at redshift z = 0.7
Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic1 for the cosmological mass density parameter, ΩB. Recent high-redshift D/H measure...
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Article
Evidence for gravitational microlensing by dark objects in the Galactic halo
THE flat rotation curves of spiral galaxies, including our own, indicate that
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Article
Observation of Comet Kohoutek at 1.4 mm
WE made observations of Comet Kohoutek at Kitt Peak with the National Radio Astronomy Observatory (NRAO) 36-foot telescope during two consecutive periods: December 27, 1973–January 2, 1974; and January 6–Janua...