Observational research on the variability and mass-loss in the AGB

AGB 变化和质量损失的观测研究

• 批准号: 15540231
• 负责人: TANABE Toshihiko
• 金额: $ 2.3万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540231/
• 关键词: Stellar Evolution; Late Stages of Stellar Evolution; Asymptotic Giant Branch Star; Mass-loss; Long Period Variables; the Magellanic Clouds; 国際研究者交流; 南アフリカ

We have surveyed for variable stars in the Large and Small Magellanic Clouds (LMC, SMC) for 3 years with the near infrared camera SIRIUS equipped on IRSF in the South African Astronomical Observatory.We constructed Period-K magnitude diagrams of detected variable stars in the LMC and SMC. We found that variables in the SMC show the similar sequences previously discovered in the LMC. Furthermore, we discovered that the previously known sequence B consists of 2 sequences and that stars belonging to one of these sequences, named C', have the similar characteristics to those belonging to the sequence C. The stars in C and C' are thought to be the Mira variables pulsating in the fundamental and first overtone mode, respectively. We also found that the sequences A and the rest of B are separated into the upper (A+, B+) and lower (A-, B-) ones, respectively. Stars in A- and B- are probably variables in the Red Giant Branch (RGB) phase while A+ and B+ are in the Asymptotic Giant Branch (AGB). By comparing the sequence C in the LMC and SMC, we found that the period-K magnitude (period-luminosity) relation depend on the metallicity in that the variables in the SMC which has lower metallicity show systematically higher luminosity in the same period.From the observation of the intermediate-age globular cluster NGC 419 in the SMC, we found that the evolved AGB stars which is in the upper part of the AGB are all variables. However, only the tip AGB stars seem to increase their amplitudes with their colors and only the most evolved ones seem to become large amplitude Mira-like variables.

我们用南非天文台IRSF上的SIRIUS近红外照相机对大麦哲伦云和小麦哲伦云（LMC，SMC）中的变星进行了3年的观测，绘制了大麦哲伦云和小麦哲伦云变星的K周期星等图。我们发现，SMC中的变量显示了以前在LMC中发现的类似序列。此外，我们还发现已知的序列B由两个序列组成，其中一个序列C '的恒星具有与序列C相似的特征。在C和C'中的恒星被认为是分别以基本和第一泛音模式脉动的Mira变星。我们还发现，序列A和其余的B分别被分成上（A+，B+）和下（A-，B-）两部分。A-和B-可能是红巨星分支（RGB）阶段的变星，而A+和B+可能是渐近巨星分支（AG B）阶段的变星。通过比较大麦哲伦云和小麦哲伦云中的C序列，我们发现，（周期-光度）关系依赖于金属丰度，即在SMC中，金属丰度较低的变星在同一周期内系统地表现出较高的光度。我们发现AGB上部的演化AGB星都是变星。然而，只有尖端AGB星似乎会随着颜色的变化而增加振幅，只有最进化的AGB星似乎会成为大振幅的Mira型变星。

项目成果

Interstellar Extinction Law in the J, H, and Ks Bands toward the Galactic Center

• DOI: 10.1086/499038
• 发表时间: 2006-01
• 期刊: The Astrophysical Journal
• 作者: S. Nishiyama;T. Nagata;N. Kusakabe;N. Matsunaga;T. Naoi;D. Kato;C. Nagashima;K. Sugitani;M. Tamura

JHKs time-series observations of a few ultracool dwarfs

JHK 对一些超冷矮星的时间序列观测

• DOI: 10.1111/j.1365-2966.2005.09280.x
• 发表时间: 2005
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: C. Koen;T. Tanabé;M. Tamura;N. Kusakabe
• 通讯作者: N. Kusakabe

Broad-band photometric colors and effective temperature calibrations for late-type giants. I. Z = 0.02

• DOI: 10.1051/0004-6361:20053028
• 发表时间: 2005-10
• 期刊: Astronomy and Astrophysics
• 影响因子: 6.5
• 作者: A. Kučinskas;P. Hauschildt;H. Ludwig;I. Brott;V. Vansevičius;L. Lindegren;T. Tanabé;F. Allard

A Distinct Structure inside the Galactic Bar

• DOI: 10.1086/429291
• 发表时间: 2005-02
• 期刊: The Astrophysical Journal Letters
• 作者: S. Nishiyama;T. Nagata;D. Baba;Y. Haba;R. Kadowaki;D. Kato;M. Kurita;C. Nagashima;T. Nagayama;Yuka Murai;Y. Nakajima;M. Tamura;H. Nakaya;K. Sugitani;T. Naoi;N. Matsunaga;T. Tanabé;N. Kusakabe;S. Sato

Variable stars in the Magellanic Clouds : The data and infrared

麦哲伦云中的变星：数据和红外

• 发表时间: 2004
• 期刊: Mon. Not. Royal Astron. Soc. 353
• 作者: Ita;Y.;Tanabe;T.et al.
• 通讯作者: T.et al.