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- ID:
- ivo://CDS.VizieR/J/A+A/394/97
- Title:
- Johnson and Stromgren photometry of V784 Cas
- Short Name:
- J/A+A/394/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new Johnson and Stromgren photometric observations of the delta Scuti type variable star V784 Cassiopeae. The data were obtained in three consecutive years between 1999 and 2001. The bulk of the measurements was made at the Sierra Nevada Observatory (Spain) with the 0.9m telescope equipped with a four-channel spectrograph photometer. UBV data were taken with the 0.4m telescope of Szeged Observatory (Hungary).
- ID:
- ivo://CDS.VizieR/J/AJ/143/4
- Title:
- Kepler cycle 1 observations of low-mass stars
- Short Name:
- J/AJ/143/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed Kepler light curves for 849 stars with Teff<=5200K from our Cycle 1 Guest Observer program. We identify six new eclipsing binaries, one of which has an orbital period of 29.91 days and two of which are probably W UMa variables. In addition, we identify a candidate "warm Jupiter" exoplanet. We further examine a subset of 670 sources for variability. Of these objects, 265 stars clearly show periodic variability that we assign to rotation of the low-mass star. At the photometric precision level provided by Kepler, 251 of our objects showed no evidence for variability. We were unable to determine periods for 154 variable objects. We find that 79% of stars with Teff<=5200K are variable. The rotation periods we derive for the periodic variables span the range 0.31days<=Prot<=126.5days. A considerable number of stars with rotation periods similar to the solar value show activity levels that are 100 times higher than the Sun.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/11
- Title:
- KIC 9777062 RVs & asteroseismology in NGC6811
- Short Name:
- J/ApJ/831/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of an eccentric, partially eclipsing long-period (P=19.23 days) binary system KIC 9777062 that contains main-sequence stars near the turnoff of the intermediate-age open cluster NGC 6811. The primary is a metal-lined Am star with a possible convective blueshift to its radial velocities, and one star (probably the secondary) is likely to be a {gamma} Dor pulsator. The component masses are 1.603+/-0.006(stat.)+/-0.016(sys.) and 1.419+/-0.003+/-0.008M_{sun}_, and the radii are 1.744+/-0.004+/-0.002 and 1.544+/-0.002+/-0.002R_{sun}_. The isochrone ages of the stars are mildly inconsistent: the age from the mass-radius combination for the primary (1.05+/-0.05+/-0.09Gyr, where the last quote was systematic uncertainty from models and metallicity) is smaller than that from the secondary (1.21+/-0.05+/-0.15Gyr) and is consistent with the inference from the color-magnitude diagram (1.00+/-0.05Gyr). We have improved the measurements of the asteroseismic parameters {Delta}{nu} and {nu}_max_ for helium-burning stars in the cluster. The masses of the stars appear to be larger (or alternately, the radii appear to be smaller) than predicted from isochrones using the ages derived from the eclipsing stars. The majority of stars near the cluster turnoff are pulsating stars: we identify a sample of 28 {delta} Sct, 15 {gamma} Dor, and 5 hybrid types. We used the period-luminosity relation for high-amplitude {delta} Sct stars to fit the ensemble of the strongest frequencies for the cluster members, finding (m-M)_V_=10.37+/-0.03. This is larger than most previous determinations, but smaller than values derived from the eclipsing binary (10.47+/-0.05).
- ID:
- ivo://CDS.VizieR/J/ApJS/246/15
- Title:
- K2 periodic variables in M35 & NGC2158
- Short Name:
- J/ApJS/246/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 1143 periodic variables, compiled from our image-subtracted photometric analysis of the K2 Campaign-0 super stamp. This super stamp is centered on the open clusters M35 and NGC2158. Approximately 46% of our periodic variables were previously unreported. Of the catalog variables, we find that 331 are members of M35 and 56 are members of NGC 2158 (P_m_>0.5). Our catalog contains two new transiting exoplanet candidates, both of which orbit field stars. The smaller planet candidate has a radius of 0.35+/-0.04R_J_ and orbits a K dwarf (Kp=15.4mag) with a transit depth of 2.9mmag. The larger planet candidate has a radius of 0.72+/-0.02R_J_ and orbits a late G-type star (Kp=15.7mag) with a transit depth of 2.2mmag. The larger planet candidate may be an unresolved binary or a false alarm. Our catalog includes 44 eclipsing binaries (EBs), including ten new detections. Of the EBs, one is an M35 member and five are NGC 2158 members. Our catalog contains a total of 1097 nontransiting variable stars, including a field {delta} Cepheid exhibiting double mode pulsations, 561 rotational variables, and 251 pulsating variables (primarily {gamma} Doradus and {delta} Scuti types). The periods of our catalog sources range between 43 minutes to 24 days. The known ages of our reported cluster variables will facilitate investigations of a variety of stellar evolutionary processes.
- ID:
- ivo://CDS.VizieR/J/AJ/162/101
- Title:
- K2 ugri & H{alpha} photometry in the Lagoon Nebula
- Short Name:
- J/AJ/162/101
- Date:
- 14 Mar 2022 06:42:13
- Publisher:
- CDS
- Description:
- Space observatories have provided unprecedented depictions of the many variability behaviors typical of low-mass, young stars. However, those studies have so far largely omitted more massive objects (~2M{sun} to 4-5M{sun}) and were limited by the absence of simultaneous, multiwavelength information. We present a new study of young star variability in the ~1-2Myr old, massive Lagoon Nebula region. Our sample encompasses 278 young, late B to K-type stars, monitored with Kepler/K2. Auxiliary u, g, r, i, H{alpha} time-series photometry, simultaneous with K2, was acquired at the Paranal Observatory. We employed this comprehensive data set and archival infrared photometry to determine individual stellar parameters, assess the presence of circumstellar disks, and tie the variability behaviors to inner disk dynamics. We found significant mass-dependent trends in variability properties, with B/A stars displaying substantially reduced levels of variability compared to G/K stars for any light-curve morphology. These properties suggest different magnetic field structures at the surface of early-type and later-type stars. We also detected a dearth of some disk-driven variability behaviors, particularly dippers, among stars earlier than G. This indicates that their higher surface temperatures and more chaotic magnetic fields prevent the formation and survival of inner disk dust structures corotating with the star. Finally, we examined the characteristic variability timescales within each light curve and determined that the day-to-week timescales are predominant over the K2 time series. These reflect distinct processes and locations in the inner disk environment, from intense accretion triggered by instabilities in the innermost disk regions to variable accretion efficiency in the outer magnetosphere.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/25
- Title:
- Light curves of RR Lyrae stars in M3 (NGC5272)
- Short Name:
- J/ApJS/219/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The overtone and multi-mode RR Lyrae stars in the globular cluster M3 are studied using a 200 day long, B,V, and l_c_ time-series photometry obtained in 2012. 70% of the 52 overtone variables observed show some kind of multi-periodicity (with additional frequency at f_0.61_=f_1O_/0.61 frequency ratio, Blazhko effect, double/multi-mode pulsation, and period doubling). A signal at the 0.587 frequency ratio to the fundamental-mode frequency is detected in the double-mode star, V13, which may be identified as the second radial overtone mode. If this mode identification is correct, then V13 is the first RR Lyrae star showing triple-mode pulsation of the first three radial modes. Either the Blazhko effect or the f_0,61_ frequency (or both of these phenomena) appears in seven double-mode stars. The P_1O_/P_F_ period ratio of RRd stars showing the Blazhko effect are anomalous. A displacement of the main frequency component at the fundamental mode with the value of modulation frequency (or its half), is detected in three Blazhko RRd stars that are parallel with the appearance of the overtone-mode pulsation. The f_0.61_ frequency appears in RRc stars that lie at the blue side of the double-mode region and in RRd stars, raising the suspicion that its occurrence may be connected to double-mode pulsation. The changes of the Blazhko and double-mode properties of the stars are also reviewed using the recent and archive photometric data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/4590
- Title:
- Light curves of RR Lyrae variables in M31
- Short Name:
- J/MNRAS/478/4590
- Date:
- 10 Dec 2021 13:45:59
- Publisher:
- CDS
- Description:
- We present an analysis of M31 RR Lyrae stars in six different fields using archival imaging from the Hubble Space Telescope. Published data for M31, M33, and several M31 dwarf spheroidal galaxies are also used to study the global properties of RR Lyrae in these systems. From the properties of RR Lyrae stars, we found that the majority of M31 and M33 RRLs are of Oosterhoff I (OoI),while those in M31 dSphs are of Oosterhoff intermediate. The main parameter affecting these Oosterhoff types is likely to be metallicity. Metallicity also plays a role in the lack of RRLs in the high amplitude short period(HASP, defined as those with P<=0.48 and A_V_>=0.75mag) variables in M31 dSphs. This difference in the properties of RRLs between their parent galaxy and satellites, as well as the lack of RRLs in the HASP region in dSphs can also be observed in the Milky Way (MW). Therefore, systems like these dSphs are unlikely to be the main building blocks of the M31 and MW halo.
- 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.
- ID:
- ivo://CDS.VizieR/V/141
- Title:
- Light-Motion Curve Catalogue (LMCC) in Stripe 82
- Short Name:
- V/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a public archive of light-motion curves in Sloan Digital Sky Survey (SDSS) Stripe 82, covering 99{deg} in right ascension (20.7h to 3.3h) and spanning 2.52{deg} in declination (-1.26 to 1.26), for a total sky area of about 249sq.deg. Stripe 82 has been repeatedly monitored in the u, g, r, i and z bands over a seven-year baseline. Objects are cross-matched between runs, taking into account the effects of any proper motion. The resulting catalogue contains almost 4million light-motion curves of stellar objects and galaxies. The photometry are recalibrated to correct for varying photometric zeropoints, achieving ~20mmag and 30mmag root-mean-square (RMS) accuracy down to 18mag in the g, r, i and z bands for point sources and extended sources, respectively. The astrometry are recalibrated to correct for inherent systematic errors in the SDSS astrometric solutions, achieving 32mas and 35mas RMS accuracy down to 18mag for point sources and extended sources, respectively. For each light-motion curve, 229 photometric and astrometric quantities are derived and stored in a higher-level catalogue. On the photometric side, these include mean exponential and PSF magnitudes along with uncertainties, RMS scatter, {chi}^2^ per degree of freedom, various magnitude distribution percentiles, object type (stellar or galaxy), and eclipse, Stetson and Vidrih variability indices. On the astrometric side, these quantities include mean positions, proper motions as well as their uncertainties and {chi}^2^ per degree of freedom. The here presented light-motion curve catalogue is complete down to r~21.5mag and is at present the deepest large-area photometric and astrometric variability catalogue available.