- ID:
- ivo://CDS.VizieR/J/AJ/153/252
- Title:
- Photometric variability of BeSS-KELT stars
- Short Name:
- J/AJ/153/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/218/20
- Title:
- Photometric variability search in the CSTAR field
- Short Name:
- J/ApJS/218/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chinese Small Telescope Array (CSTAR) is the first telescope facility built at Dome A, Antarctica. During the 2008 observing season, the installation provided long-baseline and high-cadence photometric observations in the i-band for 18145 targets within 20deg^2^ CSTAR field around the South Celestial Pole for the purpose of monitoring the astronomical observing quality of Dome A and detecting various types of photometric variability. Using sensitive and robust detection methods, we discover 274 potential variables from this data set, 83 of which are new discoveries. We characterize most of them, providing the periods, amplitudes, and classes of variability.
- ID:
- ivo://CDS.VizieR/J/A+A/317/503
- Title:
- Photometric & visibility data of IRC +10 216
- Short Name:
- J/A+A/317/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spherically symmetric dust radiative transfer code is used to model the circumstellar dust shell around IRC +10 216. Compared to numerous previous models a much larger body of observational data is used as constraints; the spectral energy distribution between 0.5 and 60000{mu}m, 2-4{mu}m and 8-23{mu}m spectra, optical, far-infrared and centimeter sizes and interferometric visibility curves between 1.6 and 11.2{mu}m are used to constrain the model. The most important result is that in order to fit the visibility curve at 2.2{mu}m and the size of the shell in the optical, scattering has to be invoked.
- ID:
- ivo://CDS.VizieR/J/AZh/78/60
- Title:
- Photometry and polarimetry of Ae star VV Ser
- Short Name:
- J/AZh/78/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of long-term photometric and polarimetric observations of the classical Herbig Ae star VV Ser, performed at the Crimean Astrophysical Observatory as part of a program of photometric and polarimetric monitoring of UX Ori stars are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/304/406
- Title:
- Photometry and radial velocities of 16 Lac
- Short Name:
- J/A+A/304/406
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic observations of the {beta} Cephei star 16 Lacertae obtained in 1983 and 1984 are presented and analysed. Using all the published maxima we have computed ephemerides for each of the three pulsational modes. No period variation is detected from 1950 to 1983. In order to identify the pulsational modes corresponding to the three main periods of 16 Lac we have applied different methods based on photometric and radial velocity variations. All give the same results: the mode corresponding to the largest amplitude P_1_ (016917d) is radial, P_2_ (017079d) is a nonradial mode of degree l=2. For P_3_ (018171d) the results are more dubious, but P_3_ is probably a l=1 nonradial mode. We have also studied the interaction between pulsation and binarity in 16 Lac. We confirm the existence of a resonance phenomenon between the radial and nonradial modes: the ratios between the beat frequencies of the pulsational modes and the orbital frequency are close but significantly different from simple rational numbers. According to Kato (1974) that means that the nonradial modes might be excited or at least enhanced by tidal effects. They would have been selected among all the possible modes because their ability to be resonant with the radial mode. The photometric amplitude of P_3_ in both filters appears to be variable from night to night in correlation with the orbital phase but despite its rapid and irregular fluctuations, the P_3_ amplitude stayed in constant average over 80 years. The present observations confirm the decrease of P_1_ and P_2_ amplitudes since 1950 but an analysis of older radial velocity data shows that the amplitude of the P_1_ mode went through a maximum around the middle of the century before the observed decrease of the last thirty years.
- ID:
- ivo://CDS.VizieR/J/A+A/498/L5
- Title:
- Photometry and spectroscopy of HD 80606b
- Short Name:
- J/A+A/498/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of the primary transit of the extra-solar planet HD80606b, thanks to photometric and spectroscopic observations performed at the Observatoire de Haute-Provence, simultaneously with the CCD camera at the 120-cm telescope and the SOPHIE spectrograph on the 193-cm telescope. We observed the whole egress of the transit and partially its central part, in both datasets with the same timings.
- ID:
- ivo://CDS.VizieR/J/A+A/516/A95
- Title:
- Photometry and spectroscopy of HD 80606b
- Short Name:
- J/A+A/516/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of a transit of the 111.4-day-period exoplanet HD80606b. Due to this long orbital period and to the orientation of the eccentric orbit (e=0.9), the HD80606b's transits last for about 12 hours. This makes practically impossible the observation of a full transit from a given ground-based observatory. Using the Spitzer Space Telescope and its IRAC camera on the post-cryogenic mission, we performed a 19-hour-long photometric observation of HD80606 that covers the full transit of 13-14 January 2010 as well as off-transit references immediately before and after the event. We complement this photometric data by new spectroscopic observations that we simultaneously performed with SOPHIE at Haute-Provence Observatory. This provides radial velocity measurements of the first half of the transit that was previously uncovered with spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A127
- Title:
- 2014-2017 photometry for ASASSN-13db
- Short Name:
- J/A+A/607/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accretion outbursts are key elements in star formation. ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest-mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted until February 2017. We explore the photometric and spectroscopic behavior of ASASSN-13db during the 2014-2017 outburst. We use high- and low-resolution spectroscopy and time-resolved photometry from the ASAS-SN survey, the LCOGT and the Beacon Observatory to study the lightcurve of ASASSN-13db and the dynamical and physical properties of the accretion flow. Results. The 2014-2017 outburst lasted for nearly 800 days. A 4.15d period in the light curve likely corresponds to rotational modulation of a star with hot spot(s). The spectra show multiple emission lines with variable inverse P-Cygni profiles and a highly variable blue-shifted absorption below the continuum. Line ratios from metallic emission lines (FeI/FeII, TiI/TiII) suggest temperatures of ~5800-6000K in the accretion flow.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1640
- Title:
- Photometry of candidate RR Lyrae stars in the SDSS
- Short Name:
- J/AJ/130/1640
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present unfiltered CCD photometry of a sample of 71 candidate RR Lyrae stars during 2003 and 2004, out of 148 candidate stars that were selected from Sloan Digital Sky Survey (SDSS) commissioning data by Ivezic and coworkers (2000AJ....120..963I). We obtain light curves of 69 candidate stars and present a catalog of their positions, amplitudes, periods, types, and mean magnitudes. We confirm that the 69 stars are true RR Lyrae variables based on periods and light curves, for the first time for 41 of them. We identify 57 type ab, 11 type c, and 1 type d (double-mode) in our sample. The double-mode RR Lyrae star shows properties similar to globular cluster stars and are unlike field stars of the Galactic halo in the Petersen diagram.
- ID:
- ivo://CDS.VizieR/J/ApJS/117/135
- Title:
- Photometry of Cepheids in Magellanic Clouds
- Short Name:
- J/ApJS/117/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report BV(RI)C data for a select group of 14 Cepheids in the Large Magellanic Cloud and eight in the Small Magellanic Cloud that have preexisting radial velocity curves. The photometry was obtained as part of a program to determine distances to these Cepheids by means of the visual surface brightness technique and to improve significantly the optical BV(RI)C light curves of Magellanic Cloud Cepheids. The data were acquired on the 0.9 m telescope at Cerro Tololo Inter-American Observatory with the CFCCD instrument and with the 1 m photometric telescope at ESO using aperture photometry. The median number of measures per Cepheid is 46 in each band, and the uncertainty in the photometry is typically 0.01 mag. Using these data together with data from the literature, we determined improved periods for all variables. For most of the Cepheids, these revised periods lead to excellent, low-noise light curves, but for a few variables, the periods are obviously variable.
