Young star V1331 Cygni takes centre stage

Choudhary, Arpita GND

With first epoch observations of HST-WFPC2 already available for V1331 Cyg from year 2000, second epoch data was observed in 2009. I study the time evolution of circumstellar nebula by analysing and comparing the two epochs of HST observations. Radial colour analysis of outer dust arc is done as well to check whether the radial grain size distribution was modified by a previous FUor wind. HST images are cleaned using IRAF and PSF subtraction is done using model PSF generated from Tiny Tim software. IDL scripts and routines are used to do proper motion analysis. The outer dust arc is found to be expanding at ≈ 14.8± 3.6 km s−1 on average. The expansion velocity of inner ring is less consistent, between 0.8 km s−1 and 3.4 km s−1. Radial colour profiles do not hint on particle separation. The results support the view that V1331 Cyg underwent an FU Orionis outburst a few thousand years ago. Additional data from other instruments - TLS, UKIDSS, SPITZER, HERSCHEL, SUBARU, PdBI and SMA is also incorporated. I use it to improve the understanding of the young star in terms of environment, viewing angle, bipolar outflow length and missing ring section. The gap between the outer and inner dust arcs is found to be real. HST planetary camera image reveals a knot like feature at 220 au from the central source. Subaru image shows scattered light in the same direction as that of the knot. Preliminary results from the latest PdBI continuum map also hint on the knot being a real feature. It is evident from the knot photometry that it is not a binary stellar companion. The starlight scattered from the dust is seen in HST images. Missing ring section could be a result of shadowing due to presence of the knot. By viewing V1331 Cyg almost pole-on, the length of the bipolar outflow is updated to be 10 parsec or even more.



Choudhary, Arpita: Young star V1331 Cygni takes centre stage. Jena 2016.


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