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HD 234386


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The N2K Consortium. VII. Atmospheric Parameters of 1907 Metal-rich Stars: Finding Planet-Search Targets
We report high-precision atmospheric parameters for 1907 stars in theN2K low-resolution spectroscopic survey, designed to identify metal-richFGK dwarfs likely to harbor detectable planets. Of these stars, 284 arein the ideal temperature range for planet searches,Teff<=6000 K, and have a 10% or greater probability ofhosting planets based on their metallicities. The stars in thelow-resolution spectroscopic survey should eventually yield >60 newplanets, including 8-9 hot Jupiters. Short-period planets have alreadybeen discovered orbiting the survey targets HIP 14810 and HD 149143.

A SCUBA Galaxy in the Protocluster around 53W002 at z=2.4
We analyze an 850 μm Submillimetre Common-User Bolometer Array(SCUBA) map of the environment of the z=2.39 radio galaxy 53W002, whichhas been shown to reside in an overdensity of Lyα-detectedgalaxies. We identify four luminous submillimeter sources within a2.3′ (1.2 Mpc at z=2.39) diameter area around the radio galaxy(which itself is a weak submillimeter source). We employ a 1.4 GHz mapto accurately locate the counterpart of one of these sources, SMMJ17142+5016, and identify this source with a narrow-line active galacticnucleus with an extended Lyα halo at z=2.390 that is a member ofthe structure around 53W002. Hence, SMM J17142+5016 is the firstspectroscopically confirmed submillimeter-selected companion to ahigh-redshift radio galaxy. We discuss the OH-Airglow SuppressionSpectrograph JHK spectrum of this galaxy and in addition present fivenew constraints on its spectral energy distribution longward of 1 μm,using these to estimate its bolometric luminosity as~8×1012 Lsolar, or a star formation rate of~103 Msolar yr-1 if young stars providethe bulk of the luminosity. This result provides direct support for thestatistical detection of overdensities of SCUBA galaxies aroundhigh-redshift radio galaxies and confirms theoretical predictions thatSCUBA galaxies, as the progenitors of massive elliptical galaxies,should be strongly clustered in the highest density regions of thedistant universe.

JHK Spectra of the z = 2.39 Radio Galaxy 53W002
We present low-resolution, near-IR JHK spectra of the weak Z=2.39 radiogalaxy 53W002, obtained with the OH-airglow Suppressor spectrograph(OHS) and Cooled Infrared Spectrograph and Camera for OHS (CISCO) on theSubaru Telescope. They cover rest-frame wavelengths of3400-7200Å, and the emission lines of [OII]λ3727, Hβ, [OIII] λλ4959, 5007,Hα/Hβ line ratio, we find an extinction of E(B-V)=0.14. Theemission-line ratios are reproduced by a cloud of electron densityne=1×103-4 cm-3 with solar metallicity,ionized by an α = -0.7 power-law continuum with ionizing parameterU = 1 × 10-3. In addition to these emission lines, wemake the first spectroscopic confirmation of the Balmer discontinuity ina high-z radio galaxy. Together with rest-frame UV photometry from theliterature, we show that at least 1/3 of the present stellar mass wasformed in the current starburst. The stellar mass was estimated to be(1-1.4) × 1011Msun by one-component model fitting,which is smaller than that of typical z ~ 1 B2/6C radio galaxies. Wesuggest that 53W002 is currently assembling a large part of its stellarmass through merger events with the surrounding sub-galactic clumps,some of which can be identified with the Lα emitters detected innarrow-band imaging. After a few such events over the next few Gyr,53W002 will evolve into a massive elliptical galaxy.

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观测天体数据

星座:天龍座
右阿森松:17h05m56.97s
赤纬:+52°01'57.1"
视星:8.306
距离:79.491 天文距离
右阿森松适当运动:-45.1
赤纬适当运动:-28.1
B-T magnitude:8.947
V-T magnitude:8.359

目录:
适当名称   (Edit)
HD 1989HD 234386
TYCHO-2 2000TYC 3507-28-1
USNO-A2.0USNO-A2 1350-09081234
HIPHIP 83660

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