The outburst of Nova Sgr 2011 N.2 (=V5588 Sgr) was followed with optical and near-IR photometric and spectroscopic observations for 3.5 years, beginning shortly before the maximum. V5588 Sgr is located close to Galactic center, suffering from E(B-V)=
1.56 (+/-0.1) extinction. The primary maximum was reached at V=12.37 on UT 2011 April 2.5 (+/-0.2), and the underlying smooth decline was moderately fast with t(2,V)=38 and t(3,V)=77 days. On top of an otherwise normal decline, six self-similar, fast evolving and bright secondary maxima (SdM) appeared in succession. Only very few other novae have presented so clear secondary maxima. Both the primary maximum and all SdM occurred at later times with increasing wavelengths, by amounts in agreement with expectations from fireball expansions. The radiative energy released during SdM declined following an exponential pattern, while the breadth of individual SdM and the time interval between them widened. Emission lines remained sharp (FWHM~1000 km/s) throughout the whole nova evolution, with the exception of a broad pedestal with a trapezoidal shape (extending for 3600 km/sec at the top and 4500 km/sec at the bottom) which was only seen during the advanced decline from SdM maxima and was absent in between SdM. V5588 Sgr at maximum light displayed a typical FeII-class spectrum which did not evolve into a nebular stage. About 10 days into the decline from primary maximum, a typical high-ionization He/N-class spectrum appeared and remained visible simultaneously with the FeII-class spectrum, qualifying V5588 Sgr as a rare hybrid nova. While the FeII-class spectrum faded into oblivion, the He/N-class spectrum developed strong [FeX] coronal lines.
We provide APASS photometry in the Landolt BV and Sloan gri bands for all the 425,743 stars included in the latest 4th RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as error of the mean of data obtained and
separately calibrated over a median of 4 distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014 and 0.021 mag for B, V, g, r and i band, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process, and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098 arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been chi2 fitted to a densely populated synthetic photometric library designed to widely explore in temperature, surface gravity, metallicity and reddening. Resulting Teff and E(B-V), computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process it is found that the reddening caused by an homogeneous slab of dust, extending for 140 pc on either side of the Galactic plane and responsible for E(B-V,poles)=0.036 +/- 0.002 at the galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b|>=25 deg.
We present a modern ephemeris and modern light curve of the first-discovered Cepheid variable in M31, Edwin Hubbles M31-V1. Observers of the American Association of Variable Star Observers undertook these observations during the latter half of 2010.
The observations were in support of an outreach program by the Space Telescope Science Institutes Hubble Heritage project, but the resulting data are the first concentrated observations of M31-V1 made in modern times. AAVSO observers obtained 214 V-band, Rc-band, and unfiltered observations from which a current ephemeris was derived. The ephemeris derived from these observations is JD(Max) = 2455430.5(+/-0.5) + 31.4 (+/-0.1) E. The period derived from the 2010 data are in agreement with the historic values of the period, but the single season of data precludes a more precise determination of the period or measurement of the period change using these data alone. However, using an ephemeris based upon the period derived by Baade and Swope we are able to fit all of the observed data acceptably well. Continued observations in the modern era will be very valuable in linking these modern data with data from the 1920s-30s and 1950s, and will enable us to measure period change in this historic Cepheid. In particular, we strongly encourage intensive observations of this star around predicted times of maximum to constrain the date of maximum to better than 0.5 days.
We present a catalog of 93 very-well-observed nova light curves. The light curves were constructed from 229,796 individual measured magnitudes, with the median coverage extending to 8.0 mag below peak and 26% of the light curves following the eruptio
n all the way to quiescence. Our time-binned light curves are presented in figures and as complete tabulations. We also calculate and tabulate many properties about the light curves, including peak magnitudes and dates, times to decline by 2, 3, 6, and 9 magnitudes from maximum, the time until the brightness returns to quiescence, the quiescent magnitude, power law indices of the decline rates throughout the eruption, the break times in this decline, plus many more properties specific to each nova class. We present a classification system for nova light curves based on the shape and the time to decline by 3 magnitudes from peak (t3). The designations are S for smooth light curves (38% of the novae), P for plateaus (21%), D for dust dips (18%), C for cusp-shaped secondary maxima (1%), O for quasi-sinusoidal oscillations superposed on an otherwise smooth decline (4%), F for flat-topped light curves (2%), and J for jitters or flares superposed on the decline (16%). Our classification consists of this single letter followed by the t3 value in parentheses; so for example V1500 Cyg is S(4), GK Per is O(13), DQ Her is D(100), and U Sco is P(3).
BZ UMa is a cataclysmic variable star whose specific classification has eluded researchers since its discovery in 1968. It has outburst and spectral properties consistent with both U Gem class dwarf novae and intermediate polars. We present new photo
metric and polarimetric measurements of recent outbursts, including the first detected superoutburst of the system. Statistical analysis of these and archival data from outbursts over the past 40 years present a case for BZ UMa as a non-magnetic, U Gem class, SU-UMa subclass dwarf novae.
AIMS: Nova Cyg 2006 has been intensively observed throughout its full outburst. We investigate the energetics and evolution of the central source and of the expanding ejecta, their chemical abundances and ionization structure, and the formation of du
st. METHOD: We recorded low, medium, and/or high-resolution spectra (calibrated into accurate absolute fluxes) on 39 nights, along with 2353 photometric UBVRcIc measures on 313 nights, and complemented them with IR data from the literature. RESULTS: The nova displayed initially the normal photometric and spectroscopic evolution of a fast nova of the FeII-type. Pre-maximum, principal, diffuse-enhanced, and Orion absorption systems developed in a normal way. After the initial outburst, the nova progressively slowed its fading pace until the decline reversed and a second maximum was reached (eight months later), accompanied by large spectroscopic changes. Following the rapid decline from second maximum, the nova finally entered the nebular phase and formed optically thin dust. We computed the amount of formed dust and performed a photo-ionization analysis of the emission-line spectrum during the nebular phase, which showed a strong enrichment of the ejecta in nitrogen and oxygen, and none in neon, in agreement with theoretical predictions for the estimated 1.0 Msun white dwarf in Nova Cyg 2006. The similarities with the poorly investigated V1493 Nova Aql 1999a are discussed.
The moderately fast Nova Oph 2007 reached maximum brightness on March 28, 2007 at V=8.52, B-V=+1.12, V-Rc=+0.76, V-Ic=+1.59 and Rc-Ic=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were t(V,2)=26.5, t(B,2)=30, t(V
,3)=48.5 and t(B,3)=56.5 days. The distance to the nova is d=3.7 kpc, the height above the galactic plane z=215 pc, the reddening E(B-V)=0.90 and the absolute magnitude at maximum M(V,max)=-7.2 and M(B,max)=-7.0. The spectrum four days before maximum resembled a F6 super-giant, in agreement with broad-band colors. It later developed into that of a standard FeII-class nova. Nine days past maximum, the expansion velocity estimated from the width of H$alpha$ emission component was 730 km/s, and the displacement from it of the principal and diffuse enhanced absorption systems were 650 and 1380 km/s, respectively. Dust probably formed and disappeared during the period from 82 to 100 days past maximum, causing (at peak dust concentration) an extinction of Delta B=1.8 mag and an extra Delta E(B-V)=0.44 reddening.
We report null results on a two year photometric search for outburst predictors in SS Cyg. Observations in Johnson V and Cousins I were obtained almost daily for multiple hours per night for two observing seasons. The accumulated data are put through
various statistical and visual analysis techniques but fails to detect any outburst predictors. However, analysis of 102 years of AAVSO archival visual data led to the detection of a correlation between a long term quasi-periodic feature at around 1,000-2,000 days in length and an increase in outburst rate.
