Siwak, Michal and Ogloza, Waldemar and Moffat, Anthony F J and Matthews, Jaymie M and Rucinski, Slavek M (2018) Photometric variability of TW Hya from seconds to years as seen from space and the ground during 2013-2017. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 478 (1). pp. 758-783. ISSN 0035-8711
|
Text
1805.04547.pdf Available under License Creative Commons Attribution. Download (15MB) | Preview |
Abstract
This is the final photometric study of TW Hya based on new MOST satellite observations. During 2014 and 2017, the light curves showed stable 3.75- and 3.69-d quasi-periodic oscillations, respectively. Both values appear to be closely related to the stellar rotation period, as they might be created by changing visibility of a hotspot formed near the magnetic pole directed towards the observer. These major light variations were superimposed on a chaotic, flaring-type activity caused by hotspots resulting from unstable accretion - a situation reminiscent of that in 2011, when TW Hya showed signs of a moderately stable accretion state. In 2015, only drifting quasi-periods were observed, similar to those present in 2008-2009 data and typical for magnetized stars accreting in a strongly unstable regime. A rich set of multicolour data was obtained during 2013-2017 with the primary aim of characterizing the basic spectral properties of the mysterious occultations in TW Hya. Although several possible occultation-like events were identified, they are not as well defined as in the 2011 MOST data. The new ground-based and MOST data show a dozen previously unnoticed flares, as well as small-amplitude 11 min-3 h brightness variations, associated with 'accretion bursts'. We cannot exclude the possibility that the shortest 11-15 min variations could also be caused by thermal instability oscillations in an accretion shock.
Item Type: | Article |
---|---|
Uncontrolled Keywords: | stars: variables: T Tauri, Herbig Ae/Be; stars: individual: TW Hya; |
Subjects: | Q Science / természettudomány > Q1 Science (General) / természettudomány általában |
SWORD Depositor: | MTMT SWORD |
Depositing User: | MTMT SWORD |
Date Deposited: | 09 Jun 2023 13:12 |
Last Modified: | 09 Jun 2023 13:12 |
URI: | http://real.mtak.hu/id/eprint/166989 |
Actions (login required)
![]() |
Edit Item |