The peculiar dipping events in the disc-bearing young-stellar object EPIC 204278916

EPIC 204278916 has been serendipitously discovered from its K2 light curve that displays irregular dimmings of up to 65 per cent for ≈25 consecutive days out of 78.8 d of observations. For the remaining duration of the observations, the variability is highly periodic and attributed to stellar rotation. The star is a young, low-mass (M-type) pre-main-sequence star with clear evidence of a resolved tilted disc from Atacama Large Millimeter/submillimeter Array (ALMA) observations. We examine the K2 light curve in detail and hypothesize that the irregular dimmings are caused by either a warped inner disc edge or transiting cometary-like objects in either circular or eccentric orbits. The explanations discussed here are particularly relevant for other recently discovered young objects with similar absorption dips

Planet Populations as a Function of Stellar Properties

Exoplanets around different types of stars provide a window into the diverse environments in which planets form. This chapter describes the observed relations between exoplanet populations and stellar properties and how they connect to planet formation in protoplanetary disks. Giant planets occur more frequently around more metal-rich and more massive stars. These findings support the core accretion theory of planet formation, in which the cores of giant planets form more rapidly in more metal-rich and more massive protoplanetary disks. Smaller planets, those with sizes roughly between Earth and Neptune, exhibit different scaling relations with stellar properties. These planets are found around stars with a wide range of metallicities and occur more frequently around lower mass stars. This indicates that planet formation takes place in a wide range of environments, yet it is not clear why planets form more efficiently around low mass stars. Going forward, exoplanet surveys targeting M dwarfs will characterize the exoplanet population around the lowest mass stars. In combination with ongoing stellar characterization, this will help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet

Detecting Weak Spectral Lines in Interferometric Data through Matched Filtering

Modern radio interferometers enable observations of spectral lines with unprecedented spatial resolution and sensitivity. In spite of these technical advances, many lines of interest are still at best weakly detected and therefore necessitate detection and analysis techniques specialized for the low signal-to-noise ratio (S/N) regime. Matched filters can leverage knowledge of the source structure and kinematics to increase sensitivity of spectral line observations. Application of the filter in the native Fourier domain improves S/N while simultaneously avoiding the computational cost and ambiguities associated with imaging, making matched filtering a fast and robust method for weak spectral line detection. We demonstrate how an approximate matched filter can be constructed from a previously observed line or from a model of the source, and we show how this filter can be used to robustly infer a detection significance for weak spectral lines. When applied to ALMA Cycle 2 observations of CH3OH in the protoplanetary disk around TW Hya, the technique yields a ≈53% S/N boost over aperture-based spectral extraction methods, and we show that an even higher boost will be achieved for observations at higher spatial resolution. A Python-based open-source implementation of this technique is available under the MIT license at http://github.com/AstroChem/VISIBLE

Distribution and evaluation of sense of coherence among older immigrants before and after a health promotion intervention – results from the RCT study promoting aging migrants’ capability

Background: The migration process can be a threat to a person’s sense of coherence (SOC) and to their ability to experience life as comprehensible, manageable, and meaningful. Seen from a salutogenic perspective, this may have a negative impact on the experience of health. Purpose: We describe the distribution of SOC and its components among older persons with an immigrant background now aging in Sweden. In addition, we evaluated whether a group-based health promotion program with a person-centered approach could support the SOC among older persons in this group. Materials and methods: A randomized controlled trial with postintervention follow-ups at 6 and 12 months was conducted with 131 independently living persons aged ≥70 years from Finland and the Balkan Peninsula. Participants were randomly allocated to an intervention group (4 weeks of group intervention and one follow-up home visit) and a control group (no intervention but access to ordinary health care services). The outcome measure was the SOC measured by SOC-13. Chi-square and ORs were calculated. Results: There was a significant improvement in total SOC scores for the intervention group at 6-month follow-up. Also, the ORs for the SOC components were higher in the person-centered intervention group. However, we found no significant between-group differences nor did the effect last until the 12-month follow-up. Conclusion: Persons who have lived a long time in a host country after migration seem to have a SOC similar to native-born persons. Interventions with a person-centered approach could support the SOC by capturing individual life situations. Such interventions could support older persons by making everyday life more comprehensible and manageable and helping them to cope with challenges in daily life caused by aging

The peculiar dipping events in the disc-bearing young-stellar object EPIC 204278916

EPIC 204278916 has been serendipitously discovered from its K2 light curve that displays irregular dimmings of up to 65 percent for =25 consecutive days out of 78.8 d of observations. For the remaining duration of the observations, the variability is highly periodic and attributed to stellar rotation. The star is a young, low-mass (M-type) pre-main-sequence star with clear evidence of a resolved tilted disc from Atacama Large Millimeter/submillimeter Array (ALMA) observations. We examine the K2 light curve in detail and hypothesize that the irregular dimmings are caused by either a warped inner disc edge or transiting cometary-like objects in either circular or eccentric orbits. The explanations discussed here are particularly relevant for other recently discovered young objects with similar absorption dips