- ID:
- ivo://CDS.VizieR/J/ApJS/113/121
- Title:
- Optically thick winds from degenerate dwarfs. I.
- Short Name:
- J/ApJS/113/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Twenty-six sequences of optically thick wind solutions have been calculated which mimic the time-dependent evolution of classical novae of populations I and II. The peak of the new opacity around log T=5.2 due to iron lines is found to be strong enough to accelerate the winds even in very low iron abundance such as Z=0.001 for massive white dwarfs (>=0.8M_{sun}_). The old population novae show the slow light curve, the long X-ray turn-off time, the small expansion velocity and the small wind mass-loss rate. The X-ray turn-off time is a good indicator of the white dwarf mass because of its strong dependence on the white dwarf mass and weak dependence on the populations. The white dwarf mass is estimated to be ~0.6M_{sun}_ for GQ Mus and ~1.0M_{sun}_ for V1974 Cyg. The systematic difference of the wind velocity is predicted between novae in globular clusters and in galactic disk. Twenty-six tables are presented in the computer readable form of CD-ROM that consists of solutions of the optically thick wind and the static for the decay phase of classical novae with composition of X=0.35, C=0.1 and O=0.2 and heavy elements content Z=0.001, 0.004, 0.02, 0.05 and 0.1 for the white dwarf masses of 0.4, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2 and 1.35M_{sun}_. These tables list the characteristic values of the envelope such as the photospheric temperature, the velocity, the wind mass-loss rate and fluxes of four wavelength bands. The updated OPAL opacity (Iglesias & Rogers, 1996ApJ...464..943I) is used.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/447/1661
- Title:
- Optical photometry of nova V5588 Sgr
- Short Name:
- J/MNRAS/447/1661
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The outburst of Nova Sgr 2011 N.2 (=V5588 Sgr) was followed with optical and near-IR photometric and spectroscopic observations for 3.5 yr, beginning shortly before the maximum. V5588 Sgr is located close to Galactic Centre, 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^V^_2_=38 and t^V^_3_=77 d. 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 SdM. 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 ({Delta}vel=3600 km/s at the top and 4500 km/s 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 d 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/274
- Title:
- Optical to NIR spectra of nova V2676 Oph 2012
- Short Name:
- J/ApJ/835/274
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H I lines from the Balmer series, FeII, NI, and [OI] lines in the initial days, typical of an Fe II type nova. The measured FWHM for the H{beta} and H{alpha} lines was 800-1200km/s. There was pronounced dust formation starting 90 days after the outburst. The J-K color was the largest among recent dust-forming novae.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/149
- Title:
- Opt/NIR obs. of M31N 2008-12a 2015 eruption
- Short Name:
- J/ApJ/833/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Andromeda Galaxy recurrent nova M31N 2008-12a had been observed in eruption 10 times, including yearly eruptions from 2008 to 2014. With a measured recurrence period of P_rec_=351+/-13days (we believe the true value to be half of this) and a white dwarf very close to the Chandrasekhar limit, M31N 2008-12a has become the leading pre-explosion supernova type Ia progenitor candidate. Following multi-wavelength follow-up observations of the 2013 and 2014 eruptions, we initiated a campaign to ensure early detection of the predicted 2015 eruption, which triggered ambitious ground- and space-based follow-up programs. In this paper we present the 2015 detection, visible to near-infrared photometry and visible spectroscopy, and ultraviolet and X-ray observations from the Swift observatory. The LCOGT 2m (Hawaii) discovered the 2015 eruption, estimated to have commenced at August 28.28+/-0.12UT. The 2013-2015 eruptions are remarkably similar at all wavelengths. New early spectroscopic observations reveal short-lived emission from material with velocities ~13000km/s, possibly collimated outflows. Photometric and spectroscopic observations of the eruption provide strong evidence supporting a red giant donor. An apparently stochastic variability during the early supersoft X-ray phase was comparable in amplitude and duration to past eruptions, but the 2013 and 2015 eruptions show evidence of a brief flux dip during this phase. The multi-eruption Swift/XRT spectra show tentative evidence of high-ionization emission lines above a high-temperature continuum. Following Henze+ (2015A&A...582L...8H), the updated recurrence period based on all known eruptions is P_rec_=174+/-10days, and we expect the next eruption of M31N 2008-12a to occur around 2016 mid-September.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/275
- Title:
- Photometric histories of recurrent novae
- Short Name:
- J/ApJS/187/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I collect virtually all photometry of the 10 known galactic recurrent novae (RNe) and their 37 known eruptions. This consists of my modern measures of nearly all archival plates (providing the only data for half of 37 known eruptions), my own 10000 CCD magnitudes from 1987 to present (providing virtually all of the magnitudes in quiescence for seven RNe), over 140000 visual magnitude estimates recorded by amateur astronomers (who discovered half the known eruptions), and the small scattering of magnitudes from all the literature. From this, I produce various uniform products: (1) BVRIJHK comparison star magnitudes and BV comparison star sequences to cover the entire range of eruption; (2) complete light curves for all eruptions; (3) best-fit B and V light curve templates; (4) orbital periods for all but one RN; (5) exhaustive searches for all missed eruptions; (6) measured discovery efficiencies since 1890; (7) true recurrence time scales; (8) predicted next eruption dates; (9) variations on time scales of minutes, hours, days, months, years, decades, and century; (10) uniform distances and extinctions to all RNe; (11) BV colors at peak and UBVRIJHK colors at minimum, all with extinction corrections; and (12) the spectral energy distributions over UBVRIJHK. Highlights of this work include the discoveries of one new RN, six previously unknown eruptions, and the orbital periods for half the RNe. The goal of this work is to provide uniform demographics for answering questions like the "What is the death rate of RNe in our Galaxy?" and "Are the white dwarfs gaining or losing mass over each eruption cycle?." An important use of this work is for the question of whether RNe can be the progenitors of Type Ia supernovae.
- ID:
- ivo://CDS.VizieR/J/PAZh/34/270
- Title:
- Photometric parameters of Galactic novae
- Short Name:
- J/PAZh/34/270
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on visual estimates by AAVSO observers, we have constructed light curves for 80 Galactic novae flared up in 1986-2006 and determined the photometric parameters m_vis_(max), t_2_, and t_3_ for 64 novae. Using the empirical relation M_V_(max)=-10.66(0.33)+2.31(0.26)*log(t_2_) (Cohen, 1985ApJ...292...90C), we have obtained the absolute magnitudes at maximum and apparent distance moduli of the novae.
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/655
- Title:
- Photometry and spectroscopy of RN LMC 1968
- Short Name:
- J/MNRAS/491/655
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive review of all observations of the eclipsing recurrent Nova LMC 1968 in the Large Magellanic Cloud which was previously observed in eruption in 1968, 1990, 2002, 2010, and most recently in 2016. We derive a probable recurrence time of 6.2+/-1.2yr and provide the ephemerides of the eclipse. In the ultraviolet-optical-IR photometry the light curve shows high variability right from the first observation around 2 d after eruption. Therefore no colour changes can be substantiated. Outburst spectra from 2016 and 1990 are very similar and are dominated by H and He lines longward of 2000{AA}. Interstellar reddening is found to be E(B-V)=0.07+/-0.01. The super soft X-ray luminosity is lower than the Eddington luminosity and the X-ray spectra suggest the mass of the white dwarf (WD) is larger than 1.3M_{sun}_. Eclipses in the light curve suggest that the system is at high orbital inclination. On day 4 after the eruption a recombination wave was observed in FeII ultraviolet absorption lines. Narrow-line components are seen after day 6 and explained as being due to reionization of ejecta from a previous eruption. The UV spectrum varies with orbital phase, in particular a component of the HeII 1640{AA} emission line, which leads us to propose that early-on the inner WD Roche lobe might be filled with a bound opaque medium prior to the re-formation of an accretion disc. Both this medium and the ejecta can cause the delay in the appearance of the soft X-ray source.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/113
- Title:
- Photometry during the 2010 eruption of U Sco
- Short Name:
- J/ApJ/742/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The eruption of the recurrent nova U Scorpii on 2010 January 28 is now the all-time best observed nova event. We report 36776 magnitudes throughout its 67 day eruption, for an average of one measure every 2.6 minutes. This unique and unprecedented coverage is the first time that a nova has had any substantial amount of fast photometry. With this, two new phenomena have been discovered: the fast flares in the early light curve seen from days 9-15 (which have no proposed explanation) and the optical dips seen out of eclipse from days 41-61 (likely caused by raised rims of the accretion disk occulting the bright inner regions of the disk as seen over specific orbital phases). The expanding shell and wind cleared enough from days 12-15 so that the inner binary system became visible, resulting in the sudden onset of eclipses and the turn-on of the supersoft X-ray source. On day 15, a strong asymmetry in the out-of-eclipse light points to the existence of the accretion stream. The normal optical flickering restarts on day 24.5. For days 15-26, eclipse mapping shows that the optical source is spherically symmetric with a radius of 4.1R_{sun}_. For days 26-41, the optical light is coming from a rim-bright disk of radius 3.4R_{sun}_. For days 41-67, the optical source is a center-bright disk of radius 2.2R_{sun}_. Throughout the eruption, the colors remain essentially constant. We present 12 eclipse times during eruption plus five just after the eruption.
- ID:
- ivo://CDS.VizieR/J/AJ/149/95
- Title:
- Photometry of nova LMC 2012
- Short Name:
- J/AJ/149/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an intensive multiwavelength campaign on nova LMC 2012. This nova evolved very rapidly in all observed wavelengths. The time to fall two magnitudes in the V band was only 2days. In X-rays the super soft phase began 13+/-5days after discovery and ended around day 50 after discovery. During the super soft phase, the Swift/XRT and Chandra spectra were consistent with the underlying white dwarf (WD) being very hot, ~1MK, and luminous, ~10^38^erg/s. The UV, optical, and near-IR photometry showed a periodic variation after the initial and rapid fading had ended. Timing analysis revealed a consistent 19.24+/-0.03hr period in all UV, optical, and near-IR bands with amplitudes of ~0.3mag which we associate with the orbital period of the central binary. No periods were detected in the corresponding X-ray data sets. A moderately high inclination system, i=60+/-10{deg}, was inferred from the early optical emission lines. The HST/STIS UV spectra were highly unusual with only the N v (1240{AA}) line present and superposed on a blue continuum. The lack of emission lines and the observed UV and optical continua from four epochs can be fit with a low mass ejection event, ~10^-6^M_{sun}_, from a hot and massive WD near the Chandrasekhar limit. The WD, in turn, significantly illuminated its subgiant companion which provided the bulk of the observed UV/optical continuum emission at the later dates. The inferred extreme WD characteristics and low mass ejection event favor nova LMC 2012 being a recurrent nova of the U Sco subclass.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A12
- Title:
- PNV J03093063+2638031 outburst evolution
- Short Name:
- J/A+A/584/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have monitored the 2014 superoutburst of the WZ Sge-type transient PNV J03093063+2638031 for more than four months, from V=11.0 maximum brightness down to V=18.4mag, close to quiescence value, by obtaining BV Rc Ic photometry and low resolution fluxed spectroscopy. The evolution was normal and no late-time 'echo' outbursts were observed. The absolute integrated flux of emission lines kept declining along the superoutburst, and their increasing contrast with the underlying continuum was simply the result of the faster decline of the continuum compared to the emission lines. Inspection of historical Harvard plates covering the 1899-1981 period did not reveal previous outbursts, neither 'normal' nor 'super'. We discovered an extended emission nebula (radius ~1-arcmin) around PNV J03093063+2638031, that became visible for a few months as the result of photo-ionization from the superoutburst of the central star. The nebula is not present on Palomar I and II sky survey images and it quickly disappeared when the outburst was over. From the rate at which the ionization front swept through the nebula, we derive a distance of ~120pc to the system. The nebula is density bounded with an outer radius of 0.03pc, and the absolute magnitude of the central star in quiescence is M_V_~14.2mag. The electron density in the nebula is estimated to be 10^5^cm^-3^ from the observed recombination time scale. Given the considerable substructures seen across the nebula, a low filling factor is inferred. Similar nebulae have not been reported for other WZ Sge objects and the challenges posed to models are considered.
