Thermal imaging of the FU Ori type object 2MASS J06593158-0405277 = V960 Mon
ATel #8168; W. P. Varricatt, T. H. Kerr, T. Carroll, E. Moore (United Kingdom Infrared Telescope, Hawaii), P. Milne (Department of Astronomy and Steward Observatory, University of Arizona)
on 15 Oct 2015; 00:45 UT
Credential Certification: Watson Varricatt (w.varricatt@ukirt.hawaii.edu)
Subjects: Infra-Red, Variables, Young Stellar Object, Pre-Main-Sequence Star
A FU Ori-type outburst of 2MASS J06593158-0405277 (V960 Mon) was discovered by Maehara, Kojima and Fujii (ATel #6770). Further observational studies (ATel #6797, #6838, #6862, #6901, #7025, #7578) and archival data research (Jurdana-Šepić & Munari, 2016, NewA, 43, 87) confirmed the FU Ori nature of this object. Kóspál et al. (2015, ApJ, 801, L5) proposed that the progenitor is a 0.75 M☉ solar mass Class-II T Tauri star of age 6 x 105 years. Caratti o Garatti et al. (2015, ApJ, 806, L4) discovered a companion to the FU Ori source, and a possible closer third source. They also detected an extended disk-like structure around the FU Ori source.
We obtained multi-epoch imaging photometric observations of this source using the 3.8-m United Kingdom Infrared Telescope (UKIRT) and The UKIRT 1-5 micron Imager Spectrometer (UIST) with the L' and M' MKO filters, at a pixel scale of 0.12"/pixel. The coordinates (J2000) of the FU Ori source and three other sources detected in its vicinity are:
2MASS J06593158-0405277 (Source A) 06:59:31.587 -04:05:27.78
2MASS J06593168-0405224 (Source B) 06:59:31.682 -04:05:22.43
Source C 06:59:31.855 -04:05:35.30
Source D 06:59:31.869 -04:05:31.94
The magnitudes measured from our observations are given in the table below. A 4"-diameter aperture was used for the FU Ori source; for the faint neighbours, a smaller aperture of diameter 2" was used and aperture corrections were done.
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UTDATE | UT | Heliocentric |Filter|2MASSJ06593158| Source B | Source C | Source D
yyyymmdd | hrs | Julian Date | |-0405277 | |
| | 2457000 + | | mag. | error| mag. | error | mag. | error | mag. | error
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20150426 |5.3725 | 138.72219 | L' | 6.711 | 0.025| 10.107 | 0.061 | 11.572 | 0.250 |
20150427 |5.4675 | 139.72607 | L' | 6.725 | 0.025| 10.228 | 0.039 | 11.325 | 0.097 |
20150905 |14.8567 | 271.11613 | L' | 6.691 | 0.025| 10.249 | 0.033 | 11.438 | 0.084 | 12.606 | 0.241
20150911 |14.7003 | 277.11006 | L' | 6.696 | 0.025| 10.262 | 0.065 | 11.502 | 0.163 |
20150426 |5.5694 | 138.73040 | M' | 6.316 | 0.02 | 9.564 | 0.176 |
20150427 |5.6354 | 139.73306 | M' | 6.338 | 0.02 | 9.544 | 0.124 |
20150905 |14.9603 | 271.12062 | M' | 6.309 | 0.02 | 9.488 | 0.157 |
20150911 |14.7934 | 277.11395 | M' | 6.314 | 0.02 | 9.666 | 0.134 |
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For V960 Mon, the brightest of the four sources, the errors measured from our photometry are better than the values given in the table. Nevertheless, as the errors in the L' and M' magnitudes of the standard star are 0.025 and 0.02 mag respectively, we have adopted those values. Sources C and D do not have 2MASS counterparts. They are detected in the K band in our UKIRT observations obtained using WFCAM. Sources B and C are located 5.54" NE and 8.5" SE, respectively, of the FU Ori source. As in the optical (Semkov 2015, ATel #
8019), our observations show that V960 Mon is continuing to be bright in the infrared. It appears to have slightly brightened in September when compared to that in April. However, note that the variations are within the error limits of the standard star. The H-K and K-L' colors of V960 Mon and source B show that both are young stellar objects.
The UKIRT is supported by NASA, and operated under an agreement among the University of Hawaii, the University of Arizona, and Lockheed Martin Advanced
Technology Center.
