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We have identified a first group of 33 new candidates for symbiotic stars (SySt) of the accreting-only variety among the 600 255 stars so far observed by the GALAH high-resolution spectroscopic survey of the Southern Hemisphere, more than doubling the number of those previously known. GALAH aims to high latitudes and this offers the possibility to sound the Galaxy for new SySt away from the usual Plane and Bulge hunting regions. In this paper we focus on SySt of the M spectral type, showing an Hα emission with a peak in excess of 0.5 above the adjacent continuum level, and not affected by coherent radial pulsations. These constraints will be relaxed in future studies. The 33 new candidate SySt were subjected to an array of follow-up confirmatory observations (X–ray/UV observations with the Swift satellite, search for optical flickering, presence of a near-UV upturn in ground-based photometric and spectroscopic data, radial velocity changes suggestive of orbital motion, variability of the emission line profiles). According to Gaia eDR3 parallaxes, the candidate new SySt are located at the tip of the Giant Branch, sharing the same distribution in M(KS) of the well established SySt. The accretion luminosities of the candidate new StSt are in the range 1−10 L⊙, corresponding to mass-accretion rates of 0.1-1 10−9 M⊙ yr−1 for WDs of 1 M⊙. The M giant of one of them presents a large Lithium over-abundance.

The B V I lightcurves of seven recent novae have been extensively mapped with daily robotic observations from Atacama (Chile). They are V1534 Sco, V1535 Sco, V2949 Oph, V3661 Oph, MASTER OT J010603. 18-744715.8, TCP J1734475-240942 and ASASSN-16ma. Five belong to the Bulge, one to SMC and another is a Galactic disk object. The two program novae detected in γ-rays by Fermi-LAT (TCP J1734475-240942 and ASASSN-16ma) are Bulge objects with unevolved companions. They distinguish themselves in showing a double-component optical lightcurve. The first component to develop is the fireball from freely-expanding, ballistic-launched ejecta with the time of passage through maximum which is strongly dependent on wavelength (∼1 day delay between B and I bands). The second component, emerging simultaneously with the nova detection in γ-rays and for this reason termed gamma, evolves at a slower pace, its optical brightness being proportional to the γ-ray flux, and its passage through maximum not dependent on wavelength. The fact that γ-rays are detected from novae at the distance of the Bulge and at peak flux levels differing by 4× seems to contradict some common belief like: only normal novae close to the Sun are detected by Fermi-LAT, most normal novae emit γ-rays, and they emit γ-rays in similar amounts. The advantages offered by high-quality photometric observations collected with only one telescope (as opposed to data provided by a number of different instruments) are discussed in connection to the actual local realization of the standard filter bandpasses and the spectrum of novae dominated by emission lines. It is shown how, for the program novae, such high-quality and single-telescope optical photometry is able to disentangle effects like: the wavelength dependence of a fireball expansion, the recombination in the flashed wind of a giant companion, the subtle presence of hiccups and plateaus, tracing the super-soft X-ray phase, and determining the time of its switch-off. The non-detection by 2MASS of the progenitor excludes a giant or a sub-giant being present in four of the program novae (V2949 Oph, V3661 Oph, TCP J18102829-2729590, and ASASSN-16ma). For the remaining three objects, by modelling the optical-IR spectral energy in quiescence it is shown that V1534 Sco contains an M3III giant, V1535 Sco a K-type giant, and MASTER OT J010603.18-744715.8 a sub-giant.

CD Ind is one of only four confirmed asynchronous polars (APs). APs are strongly magnetic cataclysmic variables of the AM Herculis subclass with the characteristic that their white dwarfs rotate a few per cent out of synchronism with their binary orbit. Theory suggests that nova eruptions disrupt previously synchronized states. Following the eruption, the system is expected to rapidly resynchronize over a timescale of centuries. The other three asynchronous polars -V1432 Aql, BY Cam and V1500 Cyg -have resynchronization time estimates ranging from 100 to more than 3500 years, with all but one being less than 1200 years. We report on the analysis of over 46000 observations of CD Ind taken between 2007 and 2016, combined with previous observations from 1996, and estimate a CD Ind resynchronization time of 6400 ± 800 years. We also estimate an orbital period of 110.820(1) minutes and a current (2016.4) white dwarf spin period of 109.6564(1) minutes.