- ID:
- ivo://CDS.VizieR/J/ApJ/825/L22
- Title:
- BVRI LCs of type Ib supernova iPTF13bvn
- Short Name:
- J/ApJ/825/L22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova (SN) iPTF13bvn in NGC 5806 was the first Type Ib SN to have been tentatively associated with a progenitor in pre-explosion images. We performed deep ultraviolet (UV) and optical Hubble Space Telescope observations of the SN site ~740 days after explosion. We detect an object in the optical bands that is fainter than the pre-explosion object. This dimming is likely not produced by dust absorption in the ejecta; thus, our finding confirms the connection of the progenitor candidate with the SN. The object in our data is likely dominated by the fading SN, implying that the pre-SN flux is mostly due to the progenitor. We compare our revised pre-SN photometry with previously proposed models. Although binary progenitors are favored, models need to be refined. In particular, to comply with our deep UV detection limit, any companion star must be less luminous than a late-O star or substantially obscured by newly formed dust. A definitive progenitor characterization will require further observations to disentangle the contribution of a much fainter SN and its environment.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/788/41
- Title:
- BVRI light curve of OGLE LMC-ECL-11893
- Short Name:
- J/ApJ/788/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the serendipitous discovery of a disk-eclipse system OGLE-LMC-ECL-11893. The eclipse occurs with a period of 468 days, a duration of about 15 days, and a deep (up to {Delta}m_I_~1.5), peculiar, and asymmetric profile. A possible origin of such an eclipse profile involves a circumstellar disk. The presence of the disk is confirmed by the H-alpha line profile from the follow-up spectroscopic observations, and the star is identified as Be/Ae type. Unlike the previously known disk-eclipse candidates, the eclipses of OGLE-LMC-ECL-11893 retain the same shape throughout the span of ~17yr (13 orbital periods), indicating no measurable orbital precession of the disk.
- ID:
- ivo://CDS.VizieR/J/AJ/161/193
- Title:
- BVRI light curve of RR Lyrea V* AX UMa
- Short Name:
- J/AJ/161/193
- Date:
- 10 Dec 2021
- Publisher:
- CDS
- Description:
- The pulsation periods of RR-Lyrae stars usually vary with time, and they are often used as probes to study the mechanism behind the variation. After the early discovery that the pulsation period of the RR-Lyrae star AXUMa decreased rapidly, in further research, we made multiband photometric observations of this star using the Sino-Thai 70cm telescope and the 60cm telescope at Yunnan Observatories, and collected its light-curve data from several photometry sky surveys. The O-C diagram confirmed that AX UMa has a rapid period decrease with a rate of -7.752{+/-}0.005days/Myr, which indicates that it is the fastest-period decreasing ab-type RR Lyrae star in the Galactic field. Moreover, the O-C residuals contain additional periodic variations. We suppose that the variation with a long period is probably caused by the light-travel time effect as the star orbits in a binary system. The calculation shows that the lower mass limit of the companion is about 1M{sun}. Combined with the full amplitudes and color indexes, we suggested that the companion is probably a hot subdwarf star. We compared the light curves of AXUMa and those of another binary evolution pulsator, OGLE-BLG-RRLYR-02792, and found that the former shows the characteristics of ab-type RR-Lyrae stars, while the latter is more like an extreme long-period c-type RR-Lyrae star. However, the absence of a bump in the light curves implies that the mass loss has occurred in the outer atmosphere of AXUMa. The special features of AXUMa make it worth more attention and further observations.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A78
- Title:
- BVRI light curves and RV curves of 65 UMa
- Short Name:
- J/A+A/542/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of stellar multiple systems provides us with important information about the stellar formation processes and can help us to estimate the multiplicity fraction in the Galaxy. 65 UMa belongs to a rather small group of stellar systems of higher multiplicity, whose inner and outer orbits are well-known. This allows us to study the long-term stability and evolution of the orbits in these systems. We obtained new photometric and spectroscopic data that when combined with interferometric data enables us to analyze the system 65 UMa and determine its basic physical properties.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A129
- Title:
- BVRI light curves of 3 eclipsing binaries
- Short Name:
- J/A+A/539/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. New and complete multi-filter light curves of the eclipsing binaries AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary eclipses for AL Cam and V338 Her. For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses. Light curve solutions provide the means to calculate the absolute parameters of the components of the systems and reliably estimate their present evolutionary status. AL Cam and V338 Her are confirmed as classical Algols of relatively low mass in similar configurations. Unlike AL Cam, however, V338 Her is still transferring matter between its components, raising interest in the determinability of the evolutionary histories of Algols. AD And is found to be a detached system in which both close stars are of age 10^9^yr and is probably a "non-classical" young triple, at an interesting stage of its dynamical evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/493/1093
- Title:
- BVRI light curves of {eta} Car
- Short Name:
- J/A+A/493/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The periodicity of 5.5 years for some observational events occurring in {eta} Carinae manifests itself across a large wavelength range and has been associated with its binary nature. These events are supposed to occur when the binary components are close to periastron. To detect the previous periastron passage of {eta} Car in 2003, we started an intensive, ground-based, optical, photometric observing campaign. We continued observing the object to monitor its photometric behavior and variability across the entire orbital cycle. Our observation program consisted of daily differential photometry from CCD images, which were acquired using a 0.8m telescope and a standard BVRI filter set at La Plata Observatory. The photometry includes the central object and the surrounding Homunculus nebula. We present up-to-date results of our observing program, including homogeneous photometric data collected between 2003 and 2008. Our observations demonstrated that {eta} Car has continued increasing in brightness at a constant rate since 1998. In 2006, it reached its brightest magnitude (V~4.7) since about 1860s. The object then suddenly reverted its brightening trend, fading to V=5.0 at the beginning of 2007, and has maintained a quite steady state since then. We continue the photometric monitoring of {eta} Car in anticipation of the next "periastron passage", predicted to occur at the beginning of 2009.
- ID:
- ivo://CDS.VizieR/J/other/NewA/53.39
- Title:
- BVRI light curves of GR Boo
- Short Name:
- J/other/NewA/53.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI light curves with complete phase coverage for the short-period (p=0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated ephemeris that shows the orbital period of GR Boo is decreasing at a rate of dP/dt=-2.36x10^-7^days/year. This decrease in its period can be explained by either mass transfer from the more massive component to the less massive one, or angular momentum exchange due to magnetic activities. We also obtained a set of revised orbital parameters using the Wilson & Devinney program. And finally, we concluded that GR Boo is a contact binary with a dark spot.
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/2559
- Title:
- BVRI light curves of GSC2314-0530
- Short Name:
- J/MNRAS/406/2559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CD photometric observations in VRI colours and spectroscopic observations of the newly discovered eclipsing binary GSC 2314-0530 (NSVS 6550671) with dMe components and a very short period of P=0.192636d are presented. The simultaneous light-curve solution and radial velocity solution allow us to determine the global parameters of GSC 2314-0530: T1=3735K; T2=3106K; M1=0.51M_{sun}_; M2=0.26M_{sun}_; R1=0.55R_{sun}_; R2=0.29R_{sun}_; L1=0.053L_{sun}_; L2=0.007L_{sun}_; i=72.5{swg}; a=1.28R_{sun}_; d=59pc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/394
- Title:
- BVRI light curves of KIC 6382916
- Short Name:
- J/MNRAS/433/394
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a multisite photometric campaign on the high-amplitude {delta} Scuti star KIC 6382916 in the Kepler field. The star was observed over a 85-d interval at five different sites in North America and Europe during 2011. Kepler photometry and ground-based multicolour light curves of KIC 6382916 are used to investigate the pulsational content and to identify the principal modes. High-dispersion spectroscopy was also obtained in order to derive the stellar parameters and projected rotational velocity. From an analysis of the Kepler time series, three independent frequencies and a few hundred combination frequencies are found. The light curve is dominated by two modes with frequencies f1=4.9107d^-1^ and f2=6.4314d^-1^. The third mode with f3=8.0350d^-1^ has a much lower amplitude. We attempt mode identification by examining the amplitude ratios and phase differences in different wavebands from multicolour photometry and comparing them to calculations for different spherical harmonic degree, l. We find that the theoretical models for f1 and f2 are in a best agreement with the observations and lead to value of l=1 modes, but the mode identification of f3 is uncertain due to its low amplitude. Non-adiabatic pulsation models show that frequencies below 6d^-1^ are stable, which means that the low frequency of f1 cannot be reproduced. This is a further confirmation that current models predict a narrower pulsation frequency range than actually observed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/413/2709
- Title:
- BVRI light curves of KIC Cepheids
- Short Name:
- J/MNRAS/413/2709
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of initial work done on selected candidate Cepheids to be observed with the Kepler space telescope. Prior to the launch, 40 candidates were selected from previous surveys and data bases. The analysis of the first 322d of Kepler photometry, and recent ground-based follow-up multicolour photometry and spectroscopy allowed us to confirm that one of these stars, V1154 Cyg (KIC 7548061), is indeed a 4.9d Cepheid. Using the phase lag method, we show that this star pulsates in the fundamental mode. New radial velocity data are consistent with previous measurements, suggesting that a long-period binary component is unlikely. No evidence is seen in the ultraprecise, nearly uninterrupted Kepler photometry for non-radial or stochastically excited modes at the micromagnitude level. The other candidates are not Cepheids, but an interesting mix of possible spotted stars, eclipsing systems and flare stars.
