Science with Laser Guide Stars: Planetary applications ESO - - PowerPoint PPT Presentation
Science with Laser Guide Stars: Planetary applications ESO Planetary Sciences Journal Club Tuesday Sep. 11, 2007 C. Dumas C. Dumas, ESO Planetary Sciences Journal Club, Tues. Sep. 11, 2007 Motivation for this presentation: 1) - Call for
altitude
from 1% to nearly 80%
Gemini North Keck-II Starfire Lick Observatory Palomar Hale
Liu and Legget, 2005, ApJ 634, 616 1st result with Keck LGS AO. The images of this free-floating L dwarf, Kelu1, reveal its binarity nature, which in turn, explains the peculiar photometric behaviour
Another paper by Gelino et al. 2006, PASP, 118, 611 reports also Keck AO-LGS monitoring of the Kelu1-AB system, which orbits
Liu et al, 2006, ApJ 647, 1393 LGS-AO at Keck is used to separate the T-dwarf into a tight (~0.1” sep.) binary system. Multi-band photometry reveals the distinctive brightening at J-band for the early/mid T-dwarf types, which is explained as a property of the ultracool photosphere for these objects. Other Keck AO-LGS observations of a cool binary are reported by Siegler et al., 2007, ApJ, 133, 2320, with a separation of 66mas and spectral types of L5 and L7.5 for both components.
Close et al, 2007, ApJ 660, 1492 LGS-AO at Keck is used to resolve two BD binary systems from the Ophiucus star forming region. The wide separation permits to carry out near-infrared spectroscopic measurement of both components. The authors claim that their measured masses for the components of Oph 11 are higher than previously reported by Jayawardhana and Ivanov, and that the system is unlikely to be of planetray mass regime.
Brown et al, 2005, ApJ 632, L45 LGS-AO at Keck is used to resolve the Trans-Neptunian Object 2003 EL61 into a binary system. The satellite orbits the primary in ~49days on an eccentric orbit. The presence of the satellite permits to assess the mass of the system (4.2 1021kg), which is evaluated to be ~30% that of Pluto-Charon.
Brown et al, 2006, ApJ 639, L43 The same team usesLGS-AO at Keck is used to search for more binary systems among the TNO population. They recover a second satellite for the 2003EL61 system, and discover a satellite to the largest TNO 2003 UB313 (Eris). The presence of small satellites Around the large TNOs 2003 EL61, 2003 UB313, points to a different formartion mechanism than in the case of Pluto.
Marchis et al, 2006, Nature 439, 565 Again, LGS-AO was used at Keck to image a subset of the population dark Trojan asteroids. The binary object 617 Patroclus was Monitored at several epochs and a very low density of 0.8g.cm3 was measured (smaller than water ice), pointing to an ice-rich porous interior for this body.
Dumas et al … in preparation First planetray result obtained with the VLT-LGS system. Both satellites of 2003 EL61 are recovered with SINFONI. The image demonstrate the high contrast achieved by the use of LGS (right) wrt seeing-limited observations (left) of the same object. In only 1/2h of integration time both satellites are detected (mag 19 and 20.5 resp). The primary body (R~17) is used to provide tip-tilt reference for the wavefront correction.
GEMINI result -with LGS-Altair Star formations in Orion