Day 446

Tuesday.

1306.3730
The structure of massive quiescent galaxies at z~3 in the CANDELS-COSMOS field
Fan et al

Use (J-L) vs (V-J) color selection criteria to search massive, quiescent galaxy candidates at 2.5<z<4.0.  Obtain 19 passive VJL-selected galaxies ("pVJL") as the possible massive quiescent galaxy candidates at z~3 by several constraints.  Find the sizes of pVJL galaxies are on average 3-4 times smaller than those of local ETGs with analogous stellar mass.  The compact size of these z~3 galaxies are on average 3-4 times smaller than those of local ETGs with analogous stellar mass.  The compact size of these z~3 galaxies can be modeled by assuming their formation at z~4-6 according to the dissipative collapse of baryons.  Up to z<4, the mass-normalized size evolution can be described by r_e propto (1+z)^-1.0.  Low Sersic index and axis ratio, with median values n~1.5 and b/a ~ 0.65 respectively, indicate most of pVJL galaxies are disk-dominated.  Despite large uncertainty, the inner region of the median mass profile of pVJL galaxies is similar to those of quiescent galaxies (QGs) at 0.5<z<2.5 and local Early-type galaxies (ETGs).  It indicates local massive ETGs have been formed according to an inside-out scenario: the compact galaxies at high redshift make up the cores of local massive ETGs and then build up the outskirts according to dissipation less minor mergers.

1306.3741
The dust tail of asteroid (2300) Phaethon
Jewitt, Li, Agarwal

Discovery of a comet-like tail (2.5e8 m) on asteroid (3200) Phaethon in optical, near perihelion.  Interpret the tail as being caused by dust particles accelerated by solar radiation pressure.  The sudden appearance and the morphology of the tail indicate that the dust particles are small, with an effective radius ~1 micrometer and a combined mass ~3e5 kg.  These particles are likely products of thermal fracture and/or desiccation cracking under the very high surface temperatures (~1000 K) experienced by Phaethon at perihelion.  The existence of the tail confirms earlier inferences about activity in this body based on the detection of anomalous brightening.  Phaethon, the presumed source of the Geminid meteoroids, is still active.

1306.3940
Clouds in the atmospheres of extrasolar planets. IV.  On the scattering greenhouse effect of CO2 ice particles: numerical radiative transfer studies
Kitzmann, Patzer, Rauer

Clouds, owing to their wavelength dependent absorption and scattering properties, have a strong impact on the climate of planetary atmospheres.  The potential greenhouse effect of CO2 ice clouds in the atmospheres of terrestrial extrasolar planets is of particular interest because it might influence the position and this the extension of the outer boundary of the classic habitable zone around MS stars.  Study the radiative effects of CO2 ice particles obtained by different numerical treatments to solve the radiative transfer equation.  The comparison between the results of a high-order discrete ordinate method and simpler two-stream methods overestimate the transmitted and reflected radiation, thereby yielding a higher scattering greenhouse effect.  For the particular case of a cool M-type dwarf the CO2 ice particles show no strong effective scattering greenhouse effect by using the high-order discrete ordinate method, whereas a positive net greenhouse effect was found in case of the two-stream radiative transfer schemes.  As a result, previous studies on the effects of CO2 ice clouds using two-stream approximations overrated the atmospheric warming caused by the scattering greenhouse effect.  Consequently, the scattering greenhouse effect of CO2 ice particles seems to be less effective than previously estimated.  In general, higher order radiative transfer methods are necessary to describe the effects of CO2 ice clouds accurately as indicated by the numerical radiative transfer studies.

1305.7428
Discovery of a probable 4-5 Jupiter-mass exoplanet to HD 95086 by direct-imaging
Rameau et al

Direct imaging of gas giant planets on wide-orbits around young stars in solar neighborhood just started; carry out a deep imaging survey in the NIR using VLT/NaCo to search for substellar companions.  Report the discovery in L' (3.8 microns) images of a probable companion orbiting at 56 Au the young (10-17 Myr), dusty, and early-type (A8) star HD 95086.  This discovery is based on observations with more than a year time-lapse.  First epoch clearly revealed the source at 10 sigma, while second epoch lacked good observing conditions, hence 3 sigma.  Tests to rule out possible artifacts.  Recovery is consistent with the signal at the first epoch but requires cleaner confirmation.  Astrometric precision suggests the companion to be comvoing with the star, wit ha 3 sigma confidence level.  The planetary nature of the source is reinforced by a non-detection in Ks-band (2.18 microns) images according to its possible extremely red Ks-L' color.  Conversely, BG contamination is rejected with good confidence level.  The luminosity yields a predicted mass of about 4-5 M_Jup (at 10-17 Myr) using "hot-start" evolutionary models, making the exoplanet with the lowest mass ever imaged around a star.