A study on the mid-infrared sources that dramatically brightened

作者：Onozato Hiroki^*; Ita Yoshifusa; Ono Kenji; Fukagawa Misato; Yanagisawa Kenshi; Izumiura Hideyuki; Nakada Yoshikazu; Matsunaga Noriyuki

来源：Publications of the Astronomical Society of Japan, 2015, 67(3): 39.

DOI：10.1093/pasj/psv008

• circumstellar matter
• infrared: stars
• stars: late-type
• stars: pre-main sequence

We present results of near-infrared (NIR) photometric and spectroscopic observations of mid-infrared (MIR) sources that brightened dramatically. Using Infrared Astronomical Satellite (IRAS), AKARI, and Wide-field Infrared Survey Explorer (WISE) point source catalogs, we found that four sources (IRAS 19574+4941, V2494 Cyg, IRAS 22343+7501, and V583 Cas) significantly brightened at MIR wavelengths over a period of 20-30 yr, depending on an interval between two different observation epoch. Little is known about these sources except V2494 Cyg, which is considered as an FU Orionis star. Our observation clearly resolves IRAS 22343+7501 into four stars (2MASS J22352345+7517076, 2MASS J22352442+7517037, [RD95] C, and 2MASS J22352497+7517113) and the first JHKs photometric data for all four sources are obtained. Two of these stars (2MASS J22352442+7517037 and 2MASS J22352497+7517113) are known as T Tau stars. Our spectroscopic observation reveals that IRAS 19574+4941 is an M-type evolved star and V583 Cas a carbon star. 2MASS J22352345+7517076 is probably a young stellar object, judging from our observation showing that it has a featureless NIR spectrum and also showed dramatic brightening in NIR (about 4 mag in the K-s band). Likely reasons for dramatic brightening in MIR are discussed in this paper.

• 出版日期2015-6
• 单位中国科学院国家天文台