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An analysis on the photometric variability of V 1490 Cyg

Evitts, Jack J (2020) An analysis on the photometric variability of V 1490 Cyg. Master of Science by Research (MScRes) thesis, University of Kent,. (KAR id:80982)

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Abstract

Variability in Young Stellar Objects (YSOs) is one of their primary characteristics. Long-term, multi-filter, high-cadence monitoring of large samples aids understanding of such sources. Although data from the HOYS citizen science project allows for such monitoring, usage of different filters introduces colour-terms to the photometric data. This thesis outlines the development of a novel colour-term correction method, improving photometric error to within a couple of percent. The corrected light curve for the YSO, V 1490 Cyg, is then discussed in detail.

The source is observed to be a quasi periodic dipper with a period of 31.447 ± 0.011 days. Long and short-term variability is observed for B, V, Rc and Ic data, with larger variability on short timescales for U and Hα. U amplitudes were observed to vary on timescales of hours, indicating the source is still accreting. No significant trends were observed in the structure function, with the amount of mass in the occulting structure seen to vary by up to a factor of 10 for both mass increase and decrease. The lower estimate of the typical accretion rate of V 1490 Cyg was found of the order 10^(−10) Mʘ/year, consistent with low levels of accretion as seen in other T-Tauri stars. Investigating the orbiting structure in V vs. V − Ic parameter space suggests low column density material with roughly ISM dust properties. Embedded in this envelope are denser, small-scale structures, most likely composed of larger dust grains. The scattering properties of this material are consistent and do not change over time. An accurate distance to both IC 5070 and V 1490 Cyg of 870 (+70, −55) pc has been determined using Gaia. Literature near-infrared (NIR) and mid-infrared (MIR) data suggest that V 1490 Cyg is most likely a CTTS, with a currently low, but variable accretion rate. It is potentially at the start of the transition into a WTTS or transition disk object. This thesis finds the nature of the variability of the source is most likely attributed to a protoplanet-induced disk warp.

Item Type: Thesis (Master of Science by Research (MScRes))
Thesis advisor: Froebrich, Dirk
Thesis advisor: Urquhart, James
Uncontrolled keywords: stars: individual: V 1490 Cyg; stars: variables: T Tauri; Herbig Ae/Be; stars: formation; pre-main sequence; Astrophysics - Astrophysics of Galaxies; Astrophysics - Solar and Stellar Astrophysics
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
SWORD Depositor: System Moodle
Depositing User: System Moodle
Date Deposited: 24 Apr 2020 10:10 UTC
Last Modified: 27 Apr 2020 11:04 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/80982 (The current URI for this page, for reference purposes)
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