Calum Morris
Gather.town id
CSF22
Poster Title
Highly variable YSOs from UKIDSS, as seen by NEOWISE and 8-m class K band spectroscopy
Institution
University of Hertfordshire
Abstract (short summary)
The two widely separated epochs of UKIDSS K band photometry yielded a sample of almost 400 highly variable YSO candidates, many located in nearby, well-studied star forming regions. Here I present a follow-up study of a set of 32 of these objects using K band spectroscopy from Subaru/IRCS and Gemini/NIFS, as well as time-series mid-infrared photometry from NEOWISE.
The sample appears to confirm one FUor, with 2 further FUor-like stars, whilst other candidates displayed a mixture of characteristics, including an EXor-like star, and others with heavily veiled spectra. Furthermore, an equally wide range of behaviours can be seen in the light-curves, notably some periodic LCs similar to dusty long-period variable AGB stars, and others possibly undergoing extreme periodic extinction events.
The sample's stars mostly reside in the Cygnus-X star formation region, which allows for comparison to other large scale YSO surveys of the complex, this consequently allows for additional high-amplitude variables to be located, by examining UKIDSS photometry for confirmed YSOs that don't appear in multiple epochs. This yielded 16 new eruptive variable candidates, including several that resemble FUor type events. This survey confirms the diversity of YSOs in the infra-red and highlights how much more we can still learn about the IR variable sky.
The sample appears to confirm one FUor, with 2 further FUor-like stars, whilst other candidates displayed a mixture of characteristics, including an EXor-like star, and others with heavily veiled spectra. Furthermore, an equally wide range of behaviours can be seen in the light-curves, notably some periodic LCs similar to dusty long-period variable AGB stars, and others possibly undergoing extreme periodic extinction events.
The sample's stars mostly reside in the Cygnus-X star formation region, which allows for comparison to other large scale YSO surveys of the complex, this consequently allows for additional high-amplitude variables to be located, by examining UKIDSS photometry for confirmed YSOs that don't appear in multiple epochs. This yielded 16 new eruptive variable candidates, including several that resemble FUor type events. This survey confirms the diversity of YSOs in the infra-red and highlights how much more we can still learn about the IR variable sky.
Plain text (extended) Summary
My poster shows the key results (thus far) from a spectroscopic analysis (in the NIR) of 37 nearby eruptive YSOs, selected from the 'Extreme infrared variables from UKIDSS' catalogue of Contreras Peña et al 2014 & Lucas et al 2017. Of these we find 2 candidate FUors, 1 EXor, a further 6 EXor-like stars in quiescence, as well as a large number of other accreting YSOs. These spectra are combined with light-curves from NEOWISE, to uncover behaviour in the time-domain. Some periodicity was noticed here, with 2 YSOs undergoing periodic extinction, as well as finding MIRA-like behaviour in 2 unusual AGB-like evolved stars. We have used the nearby nature of our sample to compare to existing YSO surveys of the SFRs in question, in particular the Cygnus-X survey of Kryukova 2014, and using their known YSO positions, we have discovered further eruptive variables within the original UKIDSS survey.
URL
c.morris6@herts.ac.uk
Poster file