The Apparently Decaying Orbit of WASP-12

We present new transit and occultation times for the hot Jupiter WASP-12b. The data are compatible with a constant period derivative: $\dot{P}=-29 \pm 3$ ms yr$^{-1}$ and $P/\dot{P}= 3.2$ Myr. However, it is difficult to tell whether we have observed orbital decay, or a portion of a 14-year apsidal precession cycle. If interpreted as decay, the star's tidal quality parameter $Q_\star$ is about $2\times 10^5$. If interpreted as precession, the planet's Love number is $0.44\pm 0.10$. Orbital decay appears to be the more parsimonious model: it is favored by $\Delta\chi^2=5.5$ despite having two fewer free parameters than the precession model. The decay model implies that WASP-12 was discovered within the final $\sim$0.2% of its existence, which is an unlikely coincidence but harmonizes with independent evidence that the planet is nearing disruption. Precession does not invoke any temporal coincidence, but does require some mechanism to maintain an eccentricity of $\approx$0.002 in the face of rapid tidal circularization. To distinguish unequivocally between decay and precession will probably require a few more years of monitoring. Particularly helpful will be occultation timing in 2019 and thereafter.Comment: 10 pages [AAS journals, in press, note added in proof

Environmental and Waste Management in Some Mining Operations in Orissa

This paper attempts to provide a survey on environmental parameters, viz. solids and liquids collected from five different mines in Orissa. These mines are (i) Dolomite Quarry, or Gomardih (Tisco) (ii) Fireclay Mines, Talabasta (Grind)(iii) Iron Ore Mines, Joribahal (Patnaik Minerals Pvt.Ltd.) (iv) Limestone Quarry,Lanjiherna (O CL) and (v) Graphite Mines, Patnagarh (T. Pradhan). The solid samples consisted of (a) top more often the undisturbed soil near the mine, (b) the overburdenlwastelspoilt dump, (c) soil from nearby paddyfield, (d) plantation area and (e) garden. These are analysed for agricultural parameters .such aspll, organic carbon content, available phosphate and potassium, heavy metals such as copper, lead, zinc, chromium etc. and bacterial count. The liquid sample consisted of water and effluent collected from (i) mine pit/flow both active and abandoned, (ii) mine discharge, (iii) mineral spring, (iv) accumulated water in mines, (v) piped water in mine office and residential colony and (vi) dug well used by mine workers. These samples were analysed for heavy metals similar to solid samples, physical parameters such as total suspended solids (TSS), total dissolved solids (TDS) and the bacterial count. The analysed results were compared with the standards set by the Bureau of Indian Standards (BIS) and Central Pollution Control Board (CPCB) and recommendations on pollution control measures and strategy by other means are made for better environmental management

Evaluation of Boundary Shear Distribution in A Meandering Channel

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

The Orbit of WASP-12b Is Decaying

WASP-12b is a transiting hot Jupiter on a 1.09 day orbit around a late-F star. Since the planet's discovery in 2008, the time interval between transits has been decreasing by 29 ± 2 ms yr⁻¹. This is a possible sign of orbital decay, although the previously available data left open the possibility that the planet's orbit is slightly eccentric and is undergoing apsidal precession. Here, we present new transit and occultation observations that provide more decisive evidence for orbital decay, which is favored over apsidal precession by a ΔBIC of 22.3 or Bayes factor of 70,000. We also present new radial-velocity data that rule out the Rømer effect as the cause of the period change. This makes WASP-12 the first planetary system for which we can be confident that the orbit is decaying. The decay timescale for the orbit is P/P˙=3.25±0.23. Interpreting the decay as the result of tidal dissipation, the modified stellar tidal quality factor is Q′⋆=1.8×10⁵

The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups

We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal knots and one dIrr. Both tidal knots are located within a prominent HI tidal tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC 3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and four HI knots. Deep CFHT imaging confirms that the optical component of AGC 208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its purported parent galaxies. Combining the results for these groups with those from the NGC 871/6/7 group reported earlier, we find that the HI properties, estimated stellar ages and baryonic content of the gas-rich dwarfs clearly distinguish tidal features from their classical counterparts. We optimistically identify four potentially long-lived tidal objects associated to three separate pairs of interacting galaxies, implying that TDGs are not readily produced during interaction events as suggested by some recent simulations. The tidal objects examined in this survey also appear to have a wider variety of properties than TDGs of similar mass formed in current simulations of interacting galaxies, which could be the result of pre- or post-formation environmental influences.Comment: 18 pages, 14 figures, accepted for publication in MNRA