59 research outputs found
Physical Relation of Source I to IRc2 in the Orion KL Region
We present mid-infrared narrow-band images of the Orion BN/KL region, and
N-band low-resolution spectra of IRc2 and the nearby radio source "I." The
distributions of the silicate absorption strength and the color temperature
have been revealed with a sub-arcsecond resolution. The detailed structure of
the 7.8 micron/12.4 micron color temperature distribution was resolved in the
vicinity of IRc2. A mid-infrared counterpart to source I has been detected as a
large color temperature peak. The color temperature distribution shows an
increasing gradient from IRc2 toward source I, and no dominant temperature peak
is seen at IRc2. The spectral energy distribution of IRc2 could be fitted by a
two-temperature component model, and the "warmer component" of the infrared
emission from IRc2 could be reproduced by scattering of radiation from source
I. IRc2 itself is not self-luminous, but is illuminated and heated by an
embedded luminous young stellar object located at source I.Comment: 20 pages, 11 figures. Minor corrections had been done in the ver.2.
Accepted for publication in PAS
Crystalline Silicate Feature of the Vega-like star HD145263
We have observed the 8-13 m spectrum (R250) of the Vega-like star
candidate HD145263 using Subaru/COMICS. The spectrum of HD145263 shows the
broad trapezoidal silicate feature with the shoulders at 9.3 m and 11.44
m, indicating the presence of crystalline silicate grains. This detection
implies that crystalline silicate may also be commonly present around Vega-like
stars. The 11.44 m feature is slightly shifted to a longer wavelength
compared to the usual 11.2-3 m crystalline forsterite feature detected
toward Herbig Ae/Be stars and T Tauri stars. Although the peak shift due to the
effects of the grain size can not be ruled out, we suggest that Fe-bearing
crystalline olivine explains the observed peak wavelength fairly well.
Fe-bearing silicates are commonly found in meteorites and most interplanetary
dust particles, which originate from planetesimal-like asteroids. According to
studies of meteorites, Fe-bearing silicate must have been formed in asteroidal
planetesimals, supporting the scenario that dust grains around Vega-like stars
are of planetesimal origin, if the observed 11.44 m peak is due to
Fe-bearing silicates.Comment: accepted for Publication in ApJ
Data Compression for optical movie data of the Tomo-e Gozen
Open House, ISM in Tachikawa, 2017.6.16統計数理研究所オープンハウス(立川)、H29.6.16ポスター発
Photometry and Polarimetry of 2010 XC: Observational Confirmation of E-type Near-Earth Asteroid Pair
Asteroid systems such as binaries and pairs are indicative of physical
properties and dynamical histories of the Small Solar System Bodies. Although
numerous observational and theoretical studies have been carried out, the
formation mechanism of asteroid pairs is still unclear, especially for
near-Earth asteroid (NEA) pairs. We conducted a series of optical photometric
and polarimetric observations of a small NEA 2010 XC in 2022 December to
investigate its surface properties. The rotation period of 2010 XC is
possibly a few to several dozen hours and color indices of 2010 XC are
derived as , , and in
the Pan-STARRS system. The linear polarization degrees of 2010 XC are a
few percent at the phase angle range of 58 to 114. We found
that 2010 XC is a rare E-type NEA on the basis of its photometric and
polarimetric properties. Taking the similarity of not only physical properties
but also dynamical integrals and the rarity of E-type NEAs into account, we
suppose that 2010 XC and 1998 WT are of common origin (i.e.,
asteroid pair). These two NEAs are the sixth NEA pair and first E-type NEA pair
ever confirmed, possibly formed by rotational fission. We conjecture that the
parent body of 2010 XC and 1998 WT was transported from the
main-belt through the resonance or Hungaria region.Comment: Resubmitted to AAS Journals. Any comments are welcom
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