* Astronomy

Title: Five planets and an independent confirmation of HD 196885Ab from Lick Observatory
Authors: D. A. Fischer, P. Driscoll, H. Isaacson, M. Giguere, G. W. Marcy, J. A. Valenti, J. T. Wright, G. W. Henry, J. A. Johnson, A. W. Howard, K. M. G. Peek, C. McCarthy

We present time series Doppler data from Lick Observatory that reveal the presence of long-period planetary companions orbiting nearby stars. The typical eccentricity of these massive planets are greater than the mean eccentricity of known exoplanets. HD30562b has Msini = 1.29 Mjup, with semi-major axis of 2.3 AU and eccentricity 0.76. The host star has a spectral type F8V and is metal rich. HD86264b has Msini = 7.0 Mjup, arel = 2.86 AU, an eccentricity, e = 0.7 and orbits a metal-rich, F7V star. HD87883b has Msini = 1.78 Mjup, arel = 3.6 AU, e = 0.53 and orbits a metal-rich K0V star. HD89307b has Msini = 1.78 Mjup, arel = 3.3 AU, e = 0.24 and orbits a G0V star with slightly subsolar metallicity. HD148427b has Msini = 0.96 Mjup, arel = 0.93 AU, eccentricity of 0.16 and orbits a metal rich K0 subgiant. We also present velocities for a planet orbiting the F8V metal-rich binary star, HD196885A. The planet has Msini = 2.58 Mjup, arel = 2.37 AU, and orbital eccentricity of 0.48, in agreement with the independent discovery by Correia et al. 2008.

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NASA is giving people a new look at the universe.
A planet-hunting space probe called Kepler has sent back its first findings since being launched from Cape Canaveral in March.
NASA officials said the spacecraft could one day determine whether there are other planets like Earth in the galaxy.

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Title: Resolving the hot dust around HD69830 and eta Corvi with MIDI and VISIR
Authors: R. Smith, M.C. Wyatt, C.A. Haniff

Most of the known debris discs exhibit cool dust in regions analogous to the Edgeworth-Kuiper Belt. However, a rare subset show hot excess from within a few AU, which is often inferred to be transient. We examine 2 such sources to place limits on their location to help distinguish between different interpretations for their origin. We use MIDI on the VLTI to observe the debris discs around eta Corvi and HD69830 using baseline lengths from 44-130m. New VISIR observations of HD69830 at 18.7um are also presented. These observations are compared with disc models to place limits on disc size. The visibility functions measured with MIDI for both sources show significant variation with wavelength across 8-13um in a manner consistent with the disc flux being well resolved, notably with a dip at 10-11.5um due to the silicate emission feature. The average ratio of visibilities measured between 10-11.5um and 8-9um is 0.934±0.015 for HD69830 and 0.880±0.013 for eta Corvi over the 4 baselines for each source, a departure of 4 and 9sigma from that expected if the discs were unresolved. HD69830 is unresolved by VISIR at 18.7um. The combined limits from MIDI and 8m imaging constrain the warm dust to lie within 0.05-2.4AU for HD69830 and 0.16-2.98AU for eta Corvi. These results represent the first resolution in the mid-IR of dust around main sequence stars. The constraints placed on the location of the dust are consistent with radii predicted by SED modelling. Tentative evidence for a common position angle for the dust at 1.7AU with that at 150AU around eta Corvi, which might be expected if the hot dust is fed from the outer disc, demonstrates the potential of this technique for constraining the origin of the dust and more generally for the study of dust in the terrestrial regions of main sequence stars.

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Title: Tidal Limits to Planetary Habitability
Authors: Rory Barnes, Brian Jackson, Richard Greenberg, Sean N. Raymond

The habitable zones of main sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for terrestrial exoplanets and may significantly affect conditions near the surface. For example, if heating rates on an exoplanet are near or greater than that on Io (where tides drive volcanism that resurface the planet at least every 1 Myr) and produce similar surface conditions, then the development of life seems unlikely. On the other hand, if the tidal heating rate is less than the minimum to initiate plate tectonics, then CO_2 may not be recycled through subduction, leading to a runaway greenhouse that sterilizes the planet. These two cases represent potential boundaries to habitability and are presented along with the range of the traditional habitable zone for main sequence, low-mass stars. We propose a revised habitable zone that incorporates both stellar insolation and tidal heating. We apply these criteria to GJ 581 d and find that it is in the traditional habitable zone, but its tidal heating alone may be insufficient for plate tectonics.

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