The potential use of mycorrhizal preparations on the turfs in urban landscape

Hric, Peter; Jančovič, J.; Kovár, Peter; Vozár, Ľuboš

doi:10.24040/actaem.2017.19.1.19-25

Cited by 1 publication

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“…Their photometric variability in the optical is also low. Observed are 0.1-0.2 mag variations, which can be modulated with the orbit (EG And), and ∼0.1 mag oscillations probably caused by a variability of the giant (see the long-term photometry of EG And and CQ Dra by Sekeráš et al 2019;Hric & Urban 1991;Hric et al 1994). However, changes in the ultraviolet and X-rays can be significant, as recently reported for SU Lyn by Lopes de Oliveira et al (2018), who measured a dramatic drop in the UV-to-X-ray luminosity ratio on a timescale of 9 months.…”

Section: Accretion-powered Symbiotics: Progenitors To Symbiotic Nova mentioning

confidence: 99%

The path to Z And-type outbursts: The case of V426 Sagittae (HBHA 1704-05)

Skopal

Shugarov

Munari

et al. 2020

A&A

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Context. The star V426 Sge (HBHA 1704-05), originally classified as an emission-line object and a semi-regular variable, brightened at the beginning of August 2018, showing signatures of a symbiotic star outburst. Aims. We aim to confirm the nature of V426 Sge as a classical symbiotic star, determine the photometric ephemeris of the light minima, and suggest the path from its 1968 symbiotic nova outburst to the following 2018 Z And-type outburst. Methods. We re-constructed an historical light curve (LC) of V426 Sge from approximately the year 1900, and used original low-(R∼500-1 500; 330-880 nm) and high-resolution (R∼11 000-34 000; 360-760 nm) spectroscopy complemented with Swift-XRT and UVOT, optical U BVR C I C and near-infrared JHKL photometry obtained during the 2018 outburst and the following quiescence. Results. The historical LC reveals no symbiotic-like activity from ∼1900 to 1967. In 1968, V426 Sge experienced a symbiotic nova outburst that ceased around 1990. From approximately 1972, a wave-like orbitally related variation with a period of 493.4 ± 0.7 days developed in the LC. This was interrupted by a Z And-type outburst from the beginning of August 2018 to the middle of February 2019. At the maximum of the 2018 outburst, the burning white dwarf (WD) increased its temperature to > ∼ 2 × 10 5 K, generated a luminosity of ∼ 7 × 10 37 (d/3.3 kpc) 2 erg s −1 and blew a wind at the rate of ∼ 3 × 10 −6 M ⊙ yr −1 . Our spectral energy distribution models from the current quiescent phase reveal that the donor is a normal M4-5 III giant characterised with T eff ∼ 3 400 K, R G ∼ 106 (d/3.3 kpc) R ⊙ and L G ∼ 1350 (d/3.3 kpc) 2 L ⊙ and the accretor is a low-mass ∼0.5 M ⊙ WD. Conclusions. During the transition from the symbiotic nova outburst to the quiescent phase, a pronounced sinusoidal variation along the orbit develops in the LC of most symbiotic novae. The following eventual outburst is of Z And-type, when the accretion by the WD temporarily exceeds the upper limit of the stable burning. At this point the system becomes a classical symbiotic star.

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Section: Accretion-powered Symbiotics: Progenitors To Symbiotic Nova mentioning

confidence: 99%