- ID:
- ivo://CDS.VizieR/J/AZh/84/147
- Title:
- Light curves of V838 Mon and V4332 Sgr
- Short Name:
- J/AZh/84/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze spectra of V838 Mon and V4332 Sgr taken in 2004-2005 using the 6m telescope of the Special Astrophysical Observatory with the UAGS and SCORPIO spectrographs. We conclude based on spectroscopy combined with archive photographs and modern CCD photometry that both peculiar red novae were binaries prior to their outbursts, and contained blue hot components that exploded. The secondary of V838 Mon is a hot B3V star, and that of V4332 Sgr is a cool M7 star.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/NewA/13.133
- Title:
- 2MASS photometry of cataclysmic variables
- Short Name:
- J/other/NewA/13.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been found using distances estimated from the period-luminosity-colours (PLCs) relation of CVs. It can be concluded that exponential function fits better to the observational z-distributions of the whole CVs in the sample, non-magnetic CVs and dwarf novae, while the sech^2^ function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158+/-14pc for the 2MASS J band limiting apparent magnitude of 15.8. The discrepancies between the theoretical and observational population studies of CVs can be at least partly removed if the sech^2^ density function is used in deriving the galactic model parameters. We estimated the vertical scaleheights of 128+/-20pc and 160+/-5pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found ~3x10^-5^pc^-3^ which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows a trend toward higher space density at low luminosity, implying an increase in the number of short-period systems.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A94
- Title:
- Mean spectrum of CP Pup in 1996
- Short Name:
- J/A+A/539/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CP Pup (Nova Pup 1942) showed outburst and quiescent characteristics indicating a very massive white dwarf, yet the standard spectroscopic dynamical analysis assuming an accretion disk yields an extremely low value for the white dwarf mass. However, some physical parameters and the accretion geometry are still poorly known. The nova was spectroscopically monitored between 1988 and 1996. We analyzed the whole data set in order to re-determine the spectroscopic period and examine its stability. We also looked for chemical anomalies in the spectrum.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A119
- Title:
- M31 luminous red nova AT 2019zhd photometry
- Short Name:
- J/A+A/646/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the follow-up campaign of the luminous red nova (LRN) AT 2019zhd, the third event of this class observed in M 31. The object was followed by several sky surveys for about five months before the outburst, during which it showed a slow luminosity rise. In this phase, the absolute magnitude ranged from M_r_=-2.8+/-0.2mag to M_r_=-5.6+/-0.1mag. Then, over a four to five day period, AT 2019zhd experienced a major brightening, reaching a peak of M_r_=-9.61+/-0.08mag and an optical luminosity of 1.4x10^39^erg/s. After a fast decline, the light curve settled onto a short-duration plateau in the red bands. Although less pronounced, this feature is reminiscent of the second red maximum observed in other LRNe. This phase was followed by a rapid linear decline in all bands. At maximum, the spectra show a blue continuum with prominent Balmer emission lines. The post-maximum spectra show a much redder continuum, resembling that of an intermediate-type star. In this phase, Halpha becomes very weak, Hbeta is no longer detectable, and a forest of narrow absorption metal lines now dominate the spectrum. The latest spectra, obtained during the post-plateau decline, show a very red continuum (Teff~3000K) with broad molecular bands of TiO, similar to those of M-type stars. The long-lasting, slow photometric rise observed before the peak resembles that of LRN V1309 Sco, which was interpreted as the signature of the common-envelope ejection. The subsequent outburst is likely due to the gas outflow following a stellar merging event. The inspection of archival HST images taken 22 years before the LRN discovery reveals a faint red source (M_F555W_=0.21+/-0.14mag, with F555W-F814W=2.96+/-0.12mag) at the position of AT 2019zhd, which is the most likely quiescent precursor. The source is consistent with expectations for a binary system including a predominant M5-type star.
- ID:
- ivo://CDS.VizieR/J/A+A/418/869
- Title:
- M31-RV evolution (1942-1993)
- Short Name:
- J/A+A/418/869
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photometric evolution of M31-RV has been investigated on 1447 plates of the Andromeda galaxy obtained over half a century with the Asiago telescopes. M31-RV is a gigantic stellar explosion that occurred during 1988 in the Bulge of M31 and that was characterized by the appearance for a few months of an M supergiant reaching M_bol_=-10. The 1988 outburst has been positively detected on Asiago plates, and it has been the only such event recorded over the period covered by the plates (1942-1993). In particular, an alleged previous outburst in 1967 is excluded by the more numerous and deeper Asiago plates, with relevant implication for the interpretative models of this unique event.
- ID:
- ivo://CDS.VizieR/J/ApJ/852/108
- Title:
- Multiwavelength obs. of gamma-ray NOVA Sco 2012
- Short Name:
- J/ApJ/852/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has recently been discovered that some, if not all, classical novae emit GeV gamma-rays during outburst, but the mechanisms involved in the production of gamma-rays are still not well understood. We present here a comprehensive multiwavelength data set-from radio to X-rays-for the most gamma-ray-luminous classical nova to date, V1324 Sco. Using this data set, we show that V1324 Sco is a canonical dusty FeII-type nova, with a maximum ejecta velocity of 2600km/s and an ejecta mass of a few x10^-5^M_{sun}_. There is also evidence for complex shock interactions, including a double-peaked radio light curve which shows high brightness temperatures at early times. To explore why V1324 Sco was so gamma-ray luminous, we present a model of the nova ejecta featuring strong internal shocks and find that higher gamma-ray luminosities result from higher ejecta velocities and/or mass-loss rates. Comparison of V1324 Sco with other gamma-ray-detected novae does not show clear signatures of either, and we conclude that a larger sample of similarly well-observed novae is needed to understand the origin and variation of gamma-rays in novae.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A123
- Title:
- Near-IR catalog of novae in VVV survey area
- Short Name:
- J/A+A/554/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared data on classical novae contain useful information about the ejected gas mass and the thermal emission by dust formed during eruption, and provide independent methods to classify the objects according to the colour of their progenitors, and the fading rate and features seen after eruption. The VISTA Variables in the Via Lactea survey (VVV) is a near-IR ESO Public Survey mapping the Milky Way bulge and southern plane. Data taken during 2010-2011 covered the entire area in the JHKs bands plus some epochs in Ks-band of the ongoing VVV variability campaign. We used the VVV data to create a near-IR catalogue of the known Galactic novae in the 562 sq. deg. area covered by VVV. We also compiled the information about novae from the variability tables of the VVV variability campaign.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/158
- Title:
- Near-IR interferometry of nova Vul 2007
- Short Name:
- J/ApJ/755/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the Palomar Testbed Interferometer (PTI) to resolve 2.2{mu}m emission from the classical nova V458 Vul 2007 over the course of several days following its discovery on 2007 August 8.54 UT. We also obtained K-band photometric data and spectra of the nova during the early days of the outburst. We also used photometric measurements from the AAVSO database. This is a unique data set offering a three-technique approach: high-resolution imaging, spectroscopy, and photometry. Our analysis shows that the nova ejecta can be modeled as an inclined disk at low inclination, i.e., low ellipticity which is consistent with the nova being in the fireball phase at which the outflowing gas is optically thick, confirmed by the presence of strong P-Cygni Balmer lines in the spectra. The expansion velocity is {approx}1700km/s, derived from the H{alpha} line. By combining the nova's angular expansion rate measured by PTI with the expansion rate measured from spectroscopy, the inferred distance to the nova is 9.9-11.4kpc. We also used the K-band fluxes and the derived size of the emission to estimate the total mass ejected from the nova {approx}4x10^-4^M_{sun}_. The quick transition of the nova from Fe II to He/N class makes V458 Vul 2007 a hybrid nova.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/436
- Title:
- New Dwarf novae in SDSS, GALEX and astrom. cat.
- Short Name:
- J/MNRAS/402/436
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By cross-matching blue objects from the Sloan Digital Sky Survey with Galaxy Evolution Explorer and the astrometric catalogues USNO-B1.0, GSC2.3 and CMC14, 64 new dwarf nova candidates with one or more observed outbursts have been identified. 14 of these systems are confirmed as cataclysmic variables through existing and follow-up spectroscopy. A study of the amplitude distribution and an estimate of the outburst frequency of these new dwarf novae and those discovered by the Catalina Real-time Transient Survey indicate that besides systems that are faint because they are farther away, there also exists a population of intrinsically faint dwarf novae with rare outbursts.
- ID:
- ivo://CDS.VizieR/J/AcA/63/135
- Title:
- New OGLEIII dwarf novae in Galactic disk
- Short Name:
- J/AcA/63/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of forty erupting cataclysmic variable stars in the OGLE-III Galactic disk fields: seventeen objects of U Gem type, four of Z Cam type, and nineteen stars showing outbursts and superoutbursts typical for SU UMa type dwarf novae. In the case of five stars we were able to estimate their supercycle lengths. The obtained lengths are in the range of 20-90 d, generally between the typical SU UMa type variables and a few objects classified as the ER UMa type variables. Since there is no significant difference between the two types but a higher mass-transfer rate resulting in more frequent outbursts and superoutbursts in the ER UMa type stars, we propose to discard this type as a separate class of variables. We note that in one of the SU UMa type stars, OGLE-GD-DN-039, we found a negative supercycle period change, in contrast to other active systems of this type. Two of the new OGLE objects showed long-duration WZ Sge-like superoutbursts followed by a sequence of echo outbursts. All stars reported in this paper are part of the OGLE-III Catalog of Variable Stars.
