- ID:
- ivo://CDS.VizieR/J/AJ/162/92
- Title:
- 126 X-rays sources around the cepheid {eta} Aql
- Short Name:
- J/AJ/162/92
- Date:
- 14 Mar 2022 07:02:20
- Publisher:
- CDS
- Description:
- X-ray bursts have recently been discovered in the Cepheids {delta}Cep and {beta}Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid {eta}Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in {delta}Cep. No X-rays were seen from the Cepheid {eta}Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/162/57
- Title:
- g- and Ks-band flux of K2-22 with LBT
- Short Name:
- J/AJ/162/57
- Date:
- 14 Mar 2022 06:59:12
- Publisher:
- CDS
- Description:
- The disintegrating planet candidate K2-22b shows periodic and stochastic transits best explained by an escaping debris cloud. However, the mechanism that creates the debris cloud is unknown. The grain size of the debris as well as its sublimation rate can be helpful in understanding the environment that disintegrates the planet. Here, we present simultaneous photometry with the g band at 0.48{mu}m and KS band at 2.1{mu}m using the Large Binocular Telescope. During an event with very low dust activity, we put a new upper limit on the size of the planet of 0.71R{Earth} or 4500km. We also detected a medium depth transit that can be used to constrain the dust particle sizes. We find that the median particle size must be larger than about 0.5-1.0{mu}m, depending on the composition of the debris. This leads to a high mass-loss rate of about 3x108kg/s, which is consistent with hydrodynamic escape models. If they are produced by some alternate mechanism such as explosive volcanism, it would require extraordinary geological activity. Combining our upper limits on the planet size with the high mass-loss rate, we find a lifetime of the planet of less than 370Myr. This drops to just 21Myr when adopting the 0.02M{Earth} mass predicted from hydrodynamical models.
- ID:
- ivo://CDS.VizieR/J/AJ/162/52
- Title:
- Census of variable stars toward Serpens Main
- Short Name:
- J/AJ/162/52
- Date:
- 14 Mar 2022 06:55:43
- Publisher:
- CDS
- Description:
- We monitored a 3deg^2^ area toward Serpens Main in the Pan-STARRS1 r, i, and z bands from 2016 April to September. Light curves of more than 11000 stars in each band were obtained, and 143 variables have been identified. Among those, 119 variables are new discoveries, while 24 variables were previously known. We present variability classes and periods of 99 stars. Of these, 81 are located in the upper giant branch, displaying long periods, while the remaining 18 variables are pre-main-sequence objects with short periods. We also identify eight eclipsing binary systems, including the known binary V0623Ser, and derive their physical parameters. According to a clustering analysis of Gaia DR2 stars in the observed field, there are 10 variable members in Serpens Main, where six members have been classified as young stellar objects in previous studies. Here we provide color-magnitude and color-color diagrams for these variables. The color variability of most variables in the color-magnitude diagrams produces the expected displacements, while the movements of cluster members point in different directions; this behavior may be associated with accretion spots or circumstellar disks.
- ID:
- ivo://CDS.VizieR/J/AJ/162/21
- Title:
- PS1 photometry of 2863 ICRF3 quasars
- Short Name:
- J/AJ/162/21
- Date:
- 14 Mar 2022 06:53:33
- Publisher:
- CDS
- Description:
- We make use of individual (epoch) detection data from the Pan-STARRS "3{pi}" survey for 2863 optical ICRF3 counterparts in the five wavelength bands g, r, i, z, and y, published as part of the Data Release 2. A dedicated method based on the Functional Principal Component Analysis is developed for these sparse and irregularly sampled data. With certain regularization and normalization constraints, it allows us to obtain uniform and compatible estimates of the variability amplitudes and average magnitudes between the passbands and objects. We find that the starting assumption of affinity of the light curves for a given object at different wavelengths is violated for several percent of the sample. The distributions of rms variability amplitudes are strongly skewed toward small values, peaking at ~0.1mag with tails stretching to 2mag. Statistically, the lowest variability is found for the r band and the largest for the reddest y band. A small "brighter-redder" effect is present, with amplitudes in y greater than amplitudes in g in 57% of the sample. The variability versus redshift dependence shows a strong decline with z toward redshift 3, which we interpret as the time dilation of the dominant time frequencies. The colors of radio-loud ICRF3 quasars are correlated with redshift in a complicated, wavy pattern governed by the emergence of brightest emission lines within the five passbands.
- ID:
- ivo://CDS.VizieR/J/AJ/162/156
- Title:
- Speckle interfero. nearby multiple stars. II
- Short Name:
- J/AJ/162/156
- Date:
- 14 Mar 2022 06:50:24
- Publisher:
- CDS
- Description:
- Long-term monitoring at the 6m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences made it possible to improve the orbits of 15 objects (HIP689, HIP3951, HIP10438, HIP43948, HIP69962, HIP95995, HIP102029, HIP102357, HIP104383, HIP105947, HIP106255, HIP108917, HIP111546, HIP113726, HIP114922) and construct an orbital solution for HIP65327 for the first time. Observations have been carried out since 2007; that is, the accumulated data correspond to an interval of 13yr. As a result, most of the orbits were classified as "accurate" using the qualitative criteria by Worley & Heintz. A comparison of the mass sums and masses of the components calculated by two independent methods was made for objects with orbital solutions. The Gaia EDR3 parallax was used to obtain the fundamental parameters, as well as the Hipparcos and Gaia DR2 parallaxes.
- ID:
- ivo://CDS.VizieR/J/AJ/162/147
- Title:
- Rotation periods of 43 TOIs with Evryscope and TESS
- Short Name:
- J/AJ/162/147
- Date:
- 14 Mar 2022 06:47:58
- Publisher:
- CDS
- Description:
- Stellar radial-velocity (RV) jitter due to surface activity may bias the RV semiamplitude and mass of rocky planets. The amplitude of the jitter may be estimated from the uncertainty in the rotation period, allowing the mass to be more accurately obtained. We find candidate rotation periods for 17 out of 35 TESS Objects of Interest (TOI) hosting <3R{Earth} planets as part of the Magellan-TESS survey, which is the first-ever statistically robust study of exoplanet masses and radii across the photoevaporation gap. Seven periods are >~3{sigma} detections, two are >~1.5{sigma}, and eight show plausible variability, but the periods remain unconfirmed. The other 18 TOIs are nondetections. Candidate rotators include the host stars of the confirmed planets L168-9b, the HD21749 system, LTT1445Ab, TOI1062b, and the L98-59 system. Thirteen candidates have no counterpart in the 1000 TOI rotation catalog of Canto Martins et al. We find periods for G3-M3 dwarfs using combined light curves from TESS and the Evryscope all-sky array of small telescopes, sometimes with longer periods than would be possible with TESS alone. Secure periods range from 1.4 to 26 days with Evryscope-measured photometric amplitudes as small as 2.1mmag in g' . We also apply Monte Carlo sampling and a Gaussian process stellar activity model from exoplanet to the TESS light curves of six TOIs to confirm the Evryscope periods.
- ID:
- ivo://CDS.VizieR/J/AJ/162/110
- Title:
- Gaia EDR3 census of the Taurus-Auriga complex
- Short Name:
- J/AJ/162/110
- Date:
- 14 Mar 2022 06:44:20
- Publisher:
- CDS
- Description:
- The Taurus-Auriga complex is the prototypical low-mass star-forming region, and provides a unique testbed of the star formation process, which left observable imprints on the spatial, kinematic, and temporal structure of its stellar population. Taurus's rich observational history has uncovered peculiarities that suggest a complicated star-forming event, such as members at large distances from the molecular clouds and evidence of an age spread. With Gaia, an in-depth study of the Taurus census is possible, to confirm membership, identify substructure, and reconstruct its star formation history. We have compiled an expansive census of the greater Taurus region, identifying spatial subgroups and confirming that Taurus is substructured across stellar density. There are two populations of subgroups: clustered groups near the clouds and sparse groups spread throughout the region. The sparse groups comprise Taurus's distributed population, which is on average older than the population near the clouds, and hosts subpopulations up to 15Myr old. The ages of the clustered groups increase with distance, suggesting that the current star formation was triggered from behind. Still, the region is kinematically coherent, and its velocity structure reflects an initial turbulent spectrum similar to Larson's Law that has been modified by dynamical relaxation. Overall, Taurus has a complicated star formation history, with at least two epochs of star formation featuring both clustered and distributed modes. Given the correlations between age and spatial distribution, Taurus might be part of a galaxy-scale star-forming event that can only begin to be understood in the Gaia era.
- ID:
- ivo://CDS.VizieR/J/AJ/162/102
- Title:
- LASSO; Robo-AO observation of 444 young stars
- Short Name:
- J/AJ/162/102
- Date:
- 14 Mar 2022 06:43:15
- Publisher:
- CDS
- Description:
- We present results from the Large Adaptive optics Survey for Substellar Objects, where the goal is to directly image new substellar companions (<70M_Jup_) at wide orbital separations (>~50au) around young (<~300Myr), nearby (<100pc), low-mass (~0.1-0.8 M{odot}) stars. We report on 427 young stars imaged in the visible (i') and near-infrared (J or H ) simultaneously with Robo-AO on the Kitt Peak 2.1m telescope and later the Maunakea University of Hawaii 2.2m telescope. To undertake the observations, we commissioned a new infrared camera for Robo-AO that uses a low-noise high-speed SAPHIRA avalanche photodiode detector. We detected 121 companion candidates around 111 stars, of which 62 companions are physically associated based on Gaia DR2 parallaxes and proper motions, another 45 require follow-up observations to confirm physical association, and 14 are background objects. The companion separations range from 2 to 1101 au and reach contrast ratios of 7.7 mag in the near-infrared compared to the primary. The majority of confirmed and pending candidates are stellar companions, with ~5 being potentially substellar and requiring follow-up observations for confirmation. We also detected a 43{+/-}9 M_Jup_ and an 81{+/-}5M_Jup_ companion that were previously reported. We found 34 of our targets have acceleration measurements detected using Hipparcos-Gaia proper motions. Of those, 58_-14_^+12^% of the 12 stars with imaged companion candidates have significant accelerations ({chi}^2^>11.8), while only 23_-6_^+11^% of the remaining 22 stars with no detected companion have significant accelerations. The significance of the acceleration decreases with increasing companion separation. These young accelerating low-mass stars with companions will eventually yield dynamical masses with future orbit monitoring.
- 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/AJ/162/100
- Title:
- PAST. II. LAMOST-Gaia-Kepler catalog of 35835 stars
- Short Name:
- J/AJ/162/100
- Date:
- 14 Mar 2022 06:40:51
- Publisher:
- CDS
- Description:
- The Kepler telescope has discovered over 4000 planets (candidates) by searching ~200000 stars over a wide range of distance (order of kpc) in our Galaxy. Characterizing the kinematic properties (e.g., Galactic component membership and kinematic age) of these Kepler targets (including the planet candidate hosts) is the first step toward studying Kepler planets in the Galactic context, which will reveal fresh insights into planet formation and evolution. In this paper, the second part of the Planets Across the Space and Time (PAST) series, by combining the data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Gaia and then applying the revised kinematic methods from PAST I, we present a catalog of kinematic properties (i.e., Galactic positions, velocities, and the relative membership probabilities among the thin disk, thick disk, Hercules stream, and the halo) as well as other basic stellar parameters for 35835 Kepler stars. Further analyses of the LAMOST-Gaia-Kepler catalog demonstrate that our derived kinematic age reveals the expected stellar activity-age trend. Furthermore, we find that the fraction of thin (thick) disk stars increases (decreases) with the transiting planet multiplicity (N_p_=0,1,2 and3+) and the kinematic age decreases with N_p_, which could be a consequence of the dynamical evolution of planetary architecture with age. The LAMOST-Gaia-Kepler catalog will be useful for future studies on the correlations between the exoplanet distributions and the stellar Galactic environments as well as ages.