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FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003--2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li {\sc I} 6708 \AA line in the spectrum suggests that the object is most likely a binary system with a B2--B3 spectral type primary companion of a luminosity $\log$ L/L$\odot$ = 3.9$\pm$0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0$\pm$0.3 kpc from the Sun., Comment: 37 pages, 13 figures

We present the results of high-resolution optical spectroscopy, low-resolution near-IR spectroscopy and near-infrared speckle interferometry of the massive young stellar object candidate V645 Cyg, acquired to refine its fundamental parameters and the properties of its circumstellar envelope. Speckle interferometry in the $H$- and $K$-bands and an optical spectrum in the range 5200--6680 \AA with a spectral resolving power of $R$ = 60 000 were obtained at the 6-m telescope of the Russian Academy of Sciences. Another optical spectrum in the range 4300--10500 \AA with $R$ = 79 000 was obtained at the 3.6-m CFHT. Low-resolution spectra in the ranges 0.46--1.4 $\mu$m and 1.4--2.5 $\mu$m with $R \sim$ 800 and $\sim$ 700, respectively, were obtained at the 3-m Shane telescope of the Lick Observatory. Using a novel kinematical method based on the non-linear modeling of the neutral hydrogen density profile in the direction toward the object, we propose a distance of $D = 4.2\pm$0.2 kpc. We also suggest a revised estimate of the star's effective temperature, T$_{\rm eff} \sim$25 000 K. We resolved the object in both $H$- and $K$-bands. We conclude that V645 Cyg is a young, massive, main-sequence star, which recently emerged from its cocoon and has already experienced its protostellar accretion stage. The presence of accretion is not necessary to account for the high observed luminosity of (2--6)$\times 10^4$ M$_{\odot}$ yr$^{-1}$. The receding part of a strong, mostly uniform outflow with a terminal velocity of $\sim$800 km s$^{-1}$ is only blocked from view far from the star, where forbidden lines form., Comment: 14 pages, 10 figures

Infrared photometry and spectroscopy covering a time span of a quarter century are presented for HD 31648 (MWC 480) and HD 163296 (MWC 275). Both are isolated Herbig Ae stars that exhibit signs of active accretion, including driving bipolar flows with embedded Herbig-Haro (HH) objects. HD 163296 was found to be relatively quiescent photometrically in its inner disk region, with the exception of a major increase in emitted flux in a broad wavelength region centered near 3 microns in 2002. In contrast, HD 31648 has exhibited sporadic changes in the entire 3-13 micron region throughout this span of time. In both stars the changes in the 1-5 micron flux indicate structural changes in the region of the disk near the dust sublimation zone, possibly causing its distance from the star to vary with time. Repeated thermal cycling through this region will result in the preferential survival of large grains, and an increase in the degree of crystallinity. The variability observed in these objects has important consequences for the interpretation of other types of observations. For example, source variability will compromise models based on interferometry measurements unless the interferometry observations are accompanied by nearly-simultaneous photometric data., Comment: 55 pages, 18 figures, 2 tables, Accepted by ApJ

We report optical photometry and optical through mid-infrared spectroscopy of the classical nova V1186 Sco. This slowly developing nova had an complex light curve with multiple secondary peaks similar to those seen in PW Vul. The time to decline 2 magnitudes, t$_2$, was 20 days but the erratic nature of the light curve makes determination of intrinsic properties based on the decline time (e.g., luminosity) problematic, and the often cited MMRD relationship of Della Valle and Livio (1995) fails to yield a plausible distance. Spectra covering 0.35 to 35 $\mu$m were obtained in two separate epochs during the first year of outburst. The first set of spectra, taken about 2 months after visible maximum, are typical of a CO-type nova with narrow line emission from \ion{H}{1}, \ion{Fe}{2}, \ion{O}{1} and \ion{He}{1}. Later data, obtained between 260 and 380 days after maximum, reveal an emerging nebular spectrum. \textit{Spitzer} spectra show weakening hydrogen recombination emission with the emergence of [\ion{Ne}{2}] (12.81 $\mu$m) as the strongest line. Strong emission from [\ion{Ne}{3}] (15.56 $\mu$m) is also detected. Photoionization models with low effective temperature sources and only marginal neon enhancement (Ne $\sim$ 1.3 Ne$_{\odot}$) are consistent with these IR fine-structure neon lines indicating that V1186 Sco did not occur on a ONeMg white dwarf. In contrast, the slow and erratic light curve evolution, spectral development, and photoionization analysis of the ejecta imply the outburst occurred on a low mass CO white dwarf. We note that this is the first time strong [\ion{Ne}{2}] lines have been detected so early in the outburst of a CO nova and suggests that the presence of mid-infrared neon lines is not directly indicative of a ONeMg nova event., Comment: 7 figures, 37 pages. Astronimocal Journal accepted

We present optical and near-infrared spectral evolution of the Galactic nova V5114 Sgr (2004) during few months after the outburst. We use multi-band photometry and line intensities derived from spectroscopy to put constrains on the distance and the physical conditions of the ejecta of V5114 Sgr. The nova showed a fast decline (t_2 \simeq 11 days) and spectral features of FeII spectroscopic class. It reached M_V = -8.7 \pm 0.2 mag at maximum light, from which we derive a distance of 7700 \pm 700 kpc and a distance from the galactic plane of about 800 pc. Hydrogen and Oxygen mass of the ejecta are measured from emission lines, leading to 10^{-6} and 10^{-7} M_\odot, respectively. We compute the filling factor of the ejecta to be in the range 0.1 -- 10^{-3} . We found the value of the filling factor to decrease with time. The same is also observed in other novae, then giving support to the idea that nova shells are not homogeneously filled in, rather being the material clumped in relatively higher density blobs less affected by the general expanding motion of the ejecta., Comment: accepted for publication in Astronomy & Astrophysics, 16 pages and 8 figures

The dust sublimation zone (DSZ) is the region of pre-main sequence (PMS) disks where dust grains most easily anneal, sublime, and condense out of the gas. Because of this, it is a location where crystalline material may be enhanced and redistributed throughout the rest of the disk. A decade-long program to monitor the thermal emission of the grains located in this region demonstrates that large changes in emitted flux occur in many systems. Changes in the thermal emission between 3 and 13.5 microns were observed in HD 31648 (MWC 480), HD 163296 (MWC 275), and DG Tau. This emission is consistent with it being produced at the DSZ, where the transition from a disk of gas to one of gas+dust occurs. In the case of DG Tau, the outbursts were accompanied by increased emission on the 10 micron silicate band on one occasion, while on another occasion it went into absorption. This requires lofting of the material above the disk into the line of sight. Such changes will affect the determination of the inner disk structure obtained through interferometry measurements, and this has been confirmed in the case of HD 163296. Cyclic variations in the heating of the DSZ will lead to the annealing of large grains, the sublimation of smaller grains, possibly followed by re-condensation as the zone enters a cooling phase. Lofting of dust above the disk plane, and outward acceleration by stellar winds and radiation pressure, can re-distribute the processed material to cooler regions of the disk, where cometesimals form. This processing is consistent with the detection of the preferential concentration of large crystalline grains in the inner few AU of PMS disks using interferometric spectroscopy with the VLTI.

Photoemission experiments with UV radiation have been performed to investigate the microphysics and charge characteristics of individual isolated dust grains of various compositions and sizes by using the electrodynamic balance facility at NASA Marshall Space Flight Center. Dust particles of 2-10 gm diameter are levitated in a vacuum chamber at pressures approximately 10(exp-5) torr and exposed to a collimated beam of UV radiation in the 120-200 nm spectral range from a deuterium lamp source with a MgF2 window. A monochromator is used to select the UV wavelength with a spectral resolution of 8 nm. The electrodynamic facility permits measurements of the charge and diameters of particles of known composition, and monitoring of photoemission rates with the incident UV radiation. Experiments have been conducted on test particles of silica and polystyrene to determine the photoelectric yields and surface equilibrium potentials when exposed to UV radiation. A brief description of an experimental procedure for photoemission studies is given and some preliminary laboratory measurements of the photoelectric yields of individual dust particles are presented.

Information about the optical characteristics and physical processes involving cosmic dust particles is vital for interpretation of astronomical observations and an understanding of the formation and processing of dust in the evolutionary cycle of matter in the interstellar medium. Cosmic dust particles are formed in a variety of astrophysical environments such as in cool stellar outflows and circumstellar envelopes. Definitive knowledge of the nature, composition, and physical processes of cosmic dust grains, however, can only be inferred from astronomical observations through laboratory experiments on the analogs of hypothesized dust particles and with modeling calculations. Laboratory investigations of the nature, composition, and optical characteristics of cosmic dust particles are being, carried out at many institutions with a variety of experimental techniques. Despite a wealth of available data, however, many basic issues remain unresolved. An experimental facility based on suspension of dust particles in electrodynamic balance in a pressure/temperature controlled environment in a cavity has been operational at the NASA Marshall Space Flight Center, and is currently being employed for studies of dust particle charging mechanisms using electron beams and with UV radiation. In this paper, we discuss two general classes of experiments under planning stages that may be simultaneously carried out on this facility for cosmic dust investigations (i) Infrared optical characteristics (extinction coefficients and scattering phase functions) of the analogs of hypothesized of cosmic dust particles, such as natural and synthetic amorphous silicates with varying compositions, amorphous carbon grains, polycyclic aromatic hydrocarbons (PAHs), and icy core-mantle particles etc. The initial spectral range under consideration is 1-25 micrometers, to be extended to the far infrared region in the future (ii) Condensation of volatile gases on nucleus dust particles to be investigated for planetary and astrophysical environments.

Knowledge of the formation and distribution of interstellar, interplanetary, and planetary dust grains, and their physical, chemical and optical characteristics provide valuable information about many issues dealing with the origin and formation of the solar system bodies, interplanetary and interstellar environments as well as various industrial processes. Understanding the microphysics of individual grains and their interaction with the surrounding, environment is key to properly model various conditions and interpret existing data. The theory and models of individual dust grains are well developed for environments that vary from dense planetary atmospheres to dusty plasmas to diffuse environments such as interplanetary space. However, experimental investigations of individual dust grains in equilibrium are less common, perhaps due to the difficulty of these experiments. Laboratory measurements of dust grains have primarily measured ensemble properties or transient properties of single grains. A technique developed in the 1950's for ion spectroscopy, generally referred to as a quadrupole trap has recently been employed as an electrodynamic balance to investigate single micron-sized dust grains and for atmospheric aerosol research. A description of the theoretical basis and the experimental setup of the electrodynamic balance being developed in our laboratory are given. This laboratory technique lends itself to many applications that relate to planetary atmospheres, heliospheric environments, pre-stellar and pre-planetary conditions, and industrial settings. We present results from some recent experiments carried out to investigate the equilibrium potential of dust grains exposed to far ultraviolet light or to an electron beam. Some future experiments using an electrodynamic balance to investigate the optical characteristics, and condensation process involving dust grains in various astrophysical environments are discussed.

A laboratory experiment has been developed at Marshall Space Flight Center to study the interaction of micron-sized particles with plasmas and FUV radiation. The intent is to investigate the conditions under which particles of various compositions and sizes become charged, or discharged, while exposed to an electron beam and/or UV radiation. This experiment uses a unique laboratory where a single charged micron size particle is suspended in a quadrupole trap and then subjected to a controlled environment. Tests are performed using different materials and sizes, ranging from 10 microns to 1 micron, to determine the particle's charge while being subjected to an electron beam and /or UV radiation. The focus of this presentation will be on preliminary results from UV photoemission tests, but past results from electron beam, secondary electron emission tests will also be highlighted. A monochromator is used to spectrally resolve UV in the 120 nm to 300 nm range. This enables photoemission measurements as a function of wavelength. Electron beam tests are conducted using I to 3 micron sized aluminum oxide particles subjected to energies between 100 eV to 3 KeV. It was found that for both positive and negative particles the potential tended toward neutrality over time with possible equilibrium potentials between -0.8 Volts and 0.8 Volts.

Knowledge of the formation, distribution, physical, chemical and optical characteristics of interstellar, interplanetary, and planetary dust grains provide valuable information about many issues dealing with the origin and formation of the solar system bodies, interplanetary and interstellar environments as well as various industrial processes. Understanding the microphysics of individual grains and their interaction with the surrounding environment is key to properly model various conditions and interpret existing data. The theory and models of individual dust grains are well developed for environments that vary from dense planetary atmospheres to dusty plasmas to diffuse environments such is interplanetary space. However, experimental investigations of individual dust grains in equilibrium are less common, perhaps due to the difficult of these experiments. Laboratory measurements of dust grains have primarily measured ensemble properties or transient properties of single grains. A technique developed in the 1950's for ion spectroscopy, known as a quadrupole trap or 'Paul Trap', has recently been used to investigate single micron-sized dust grains. This scaled ion trap called an electrodynamic balance has been used for atmospheric aerosol research. A description of this technique is provided. Recent results from experiments to investigate the equilibrium potential of dust grains exposed to far ultraviolet light or to -,in electron or ion beam are presented. This laboratory technique ]ends itself to many applications that relate to planetary atmospheres, heliospheric environments, pre-stellar and pre-planetary conditions, and industrial settings. Several planned experimental approaches are presented. Potential experiments to investigate the interaction of multiple dust grains using an electrodynamic balance are proposed.

The interaction of micron sized particles or "dust particles" with different space and planetary environments has become an important area of research. One particular area of interest is how dust particles interact with plasmas. Studies have shown that charged dust particles immersed in plasmas can alter plasma characteristics, while ions and electrons in plasmas can affect a particle's potential and thereby, its interaction with other particles. The basis for understanding these phenomena is the charging mechanisms of the dust particle, specifically, how the particle's charge and characteristics are affected when exposed to ions and electrons. At NASA Marshall Space Flight Center, a laboratory experiment has been developed to study the interaction of dust particles with electrons. Using a unique laboratory technique known as electrodynamic suspension, a single charged particle is suspended in a modified quadrupole trap. Once suspended, the particle is then exposed to an electron beam to study the charging/discharging mechanisms due to collisions of energetic electrons. The change in the particle's charge, approximations of the charging/discharging currents, and the charging/discharging yield are calculated.