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2012-02

A Near-infrared Polarization Study of the BIP14 Bipolar Nebula

【日時】2月22日(水) 10:30~12:00
【場所】国立天文台・三鷹 中央棟(北)1階 講義室
【発表者(敬称略)】Sukom Amnart(総研大 D1・三鷹、指導教員 : 田村 元秀)
【タイトル】A Near-infrared Polarization Study of the BIP14 Bipolar Nebula
【アブストラクト】
We present new J(1.25um), H(1.63um) and Ks(2.15um) linear imaging polarimetric observations of bipolar nebula BIP14.
BIP 14 is excited by four stars of spectral types B0.5-A5 and has 3 lobes of nebulosity. The two bright lobes are bisected by a central dust lane (the dust disk) which is obviously identified in infrared observations. The polarization maps of two main lobes
show symmetric pattern about a single illuminating source in the main eastern lobe. The low polarization degrees of the main inner lobes (< 10 percent in J,H and Ks wavelengths) show this bipolar nebula is an combination of emission and reflection nebulosity . In addition, the position of trapezium stars in optical wavelengths, radio continuum observations and IRAS source are agreed with these infrared observations.

Orbit determination for R Aquarii

【日時】2月8日(水) 10:30~12:00
【場所】国立天文台・三鷹 中央棟(北)1階 講義室
【発表者(敬称略)】(総研大 Min Cheul Hong M2・三鷹、指導教員 : 本間 希樹)
【タイトル】
Orbit determination for R Aquarii
【アブストラクト】
R Aqr is one of the closest symbiotic systems and the only D-type system with radial velocity data suitable for orbital parameter estimation. The aims of our study are to determine reliable orbital parameters of R Aqr, and to establish connections between the orbital motion and other phenomena exhibited in this system.
R Aquarii (R Aqr) is a symbiotic system composed of a mass losing Mira long period variable and hot white dwarf companion which is believed to have an accretion disk. Interesting thing in this system is presence of a jet. A lot of orbital solutions were published, but came up with different results had wide range. Though observations of the system have not yielded consistent values of the orbital parameters, the binary parameters of the orbit determine whether or not Roche lobe outflow of the long period variable is a possibility or if interacting stellar winds are necessary to the jet and formation of accretion disk. Futermore, R Aqr is one of the only two symbiotics to have circumstellar masers asscoiated with the Mira so that VLBI observation gives us a great chance for studying symbiotic system beyond AGB stars.
In this presentation, we introduce the symbiotic system, R Aqr, expected orbital model from radial velocity data, and the VERA observation results so far achieved.

Home > Archives > 2012-02

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