- ID:
- ivo://CDS.VizieR/J/AJ/152/2
- Title:
- Photometry and spectroscopy of NP Per
- Short Name:
- J/AJ/152/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NP Per is a well-detached, 2.2 day eclipsing binary whose components are both pre-main-sequence stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420+/-90K for the larger F5 primary star and 4540+/-160K for the smaller K5e star. Their masses and radii are 1.3207+/-0.0087 solar masses and 1.372+/-0.013 solar radii for the primary, and 1.0456+/-0.0046 solar masses and 1.229+/-0.013 solar radii for the secondary. The orbital period is variable over long periods of time. A comparison of the observations with current stellar evolution models from MESA indicates that the stars cannot be fit at a single age: the secondary appears significantly younger than the primary. If the stars are assumed to be coeval and to have the age of the primary (17Myr), then the secondary is larger and cooler than predicted by current models. The H{alpha} spectral line of the secondary component is completely filled by, presumably, chromospheric emission due to a magnetic activity cycle.
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- ID:
- ivo://CDS.VizieR/J/AJ/150/200
- Title:
- Photometry and spectroscopy of stars in Cz 30
- Short Name:
- J/AJ/150/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric and spectroscopic data of the old open cluster Czernik 30. Wide field BVI photometry allows us to correct for the high field contamination by statistical subtraction to produce a color-magnitude diagram (CMD) that clearly reveals the cluster sequence. From spectra of stars in the cluster field obtained with the Hydra spectrograph on the Wisconsin-Indiana-Yale-NOAO 3.5m telescope we determine a mean cluster velocity of +79.9+/-1.5km/s and provide membership information that helps further define the cluster giant branch and red clump. Stellar abundances for the brighter giants in the cluster indicate a mean metallicity of [Fe/H]=-0.2+/-0.15. Fitting theoretical isochrones to the CMD we determine the following properties of Czernik 30: age=2.8+/-0.3Gyr, (m-M)_v_=14.8+/-0.1, E(B-V)=0.24+/-0.06, and E(V-I)=0.36+/-0.04. Czernik 30 is an old, sub-solar metallicity cluster located at a Galactocentric radius of R_gc_~13.3kpc. Given its age and position just beyond the transition to a flat abundance gradient seen in the open cluster population, Czernik 30 provides an interesting target for future observations.
- ID:
- ivo://CDS.VizieR/J/AJ/150/154
- Title:
- Photometry and spectroscopy of V501 Mon
- Short Name:
- J/AJ/150/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report extensive high-resolution spectroscopic observations and V-band differential photometry of the slightly eccentric 7.02day detached eclipsing binary V501 Mon (A6m+F0), which we use to determine its absolute dimensions to high precision (0.3% for the masses and 1.8% for the radii, or better). The absolute masses, radii, and temperatures are M_A_=1.6455+/-0.0043M_{sun}_, R_A_=1.888+/-0.029R_{sun}_, and T_eff_^A^=7510+/-100K for the primary and M_B_=1.4588+/-0.0025M_{sun}_, R_B_=1.592+/-0.028R_{sun}_, and T_eff_^B^=7000+/-90K for the secondary. Apsidal motion has been detected, to which General Relativity contributes approximately 70%. The primary star is found to be a metallic-line A star. A detailed chemical analysis of the disentangled spectra yields abundances for more than a dozen elements in each star. Based on the secondary, the system metallicity is near solar: [Fe/H]=+0.01+/-0.06. Lithium is detected in the secondary but not in the primary. A comparison with current stellar evolution models shows a good match to the measured properties at an age of about 1.1Gyr.
- ID:
- ivo://CDS.VizieR/J/AJ/131/375
- Title:
- Photometry and velocities of Sculptor dSph giants
- Short Name:
- J/AJ/131/375
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the spatial distribution of stars in the Sculptor dwarf spheroidal (dSph) galaxy over an area of 7.82deg^2^, including coverage of the central region but extending mostly south and east of the dSph core. Two methods are used to identify stars that are most likely associated with the dSph, and these filtered samples of stars are used to map its spatial structure. First, following the method of previous contributions in this series, we utilize Washington M, T_2_+DDO51 photometry to identify red giant branch (RGB) star candidates with approximately the same distance and metallicity as the Sculptor dSph. Second, a prominent blue horizontal branch (BHB) population provides a fairly populous and pure sample of Sculptor stars having broadband colors unlike the bulk of the Galactic field star population. A spectroscopically observed subset of Sculptor candidate stars (147 total stars: ~5% of all Sculptor candidates and ~10% of Sculptor giant candidates) yields a systemic heliocentric velocity for the system of v_hel_=110.43+/-0.79km/s, in good agreement with previous studies.
- ID:
- ivo://CDS.VizieR/J/AJ/147/104
- Title:
- Photometry and velocities of 1SWASP J093010A and B
- Short Name:
- J/AJ/147/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Among quadruples or higher multiplicity stars, only a few doubly eclipsing binary systems have been discovered. They are important targets for understanding the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object, 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual point-spread function photometry for two objects with a separation of about 1.9" was performed for the first time in this study. Our time-series photometric data confirms the finding of Lohr et al. that the bright object A is an Algol-type detached eclipsing binary and the fainter B is a W UMa-type contact eclipsing. Using high-resolution optical spectra, we obtained well-defined radial velocity variations of system A. Furthermore, stationary spectral lines were detected that must have originated from a further, previously unrecognized stellar component. It was confirmed by the third object contribution from the light-curve analysis. No spectral feature of system B was detected, probably due to motion blur by long exposure times. We obtained the binary parameters and the absolute dimensions of systems A and B from light-curve synthesis with and without radial velocities, respectively. The primary and secondary components of system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations for both binaries are satisfactorily modeled by using two-spot models with one starspot on each component. We estimated the distances to systems A and B individually. Two systems may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).
- ID:
- ivo://CDS.VizieR/J/ApJ/742/123
- Title:
- Photometry and Velocity of LSPM J1112+7626
- Short Name:
- J/ApJ/742/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (I_C_=12.14+/-0.05) very low mass binary system with an orbital period of 41.03236+/-0.00002 days, and component masses M_1_=0.395+/-0.002M_{sun}_ and M_2_=0.275+/-0.001M_{sun}_ in an eccentric (e=0.239+/-0.002) orbit. A 65 day out-of-eclipse modulation of approximately 2% peak-to-peak amplitude is seen in I-band, which is probably due to rotational modulation of photospheric spots on one of the binary components. This paper presents the discovery and characterization of the object, including radial velocities sufficient to determine both component masses to better than 1% precision, and a photometric solution. We find that the sum of the component radii, which is much better determined than the individual radii, is inflated by 3.8^+0.9^_-0.5_% compared to the theoretical model predictions, depending on the age and metallicity assumed. These results demonstrate that the difficulties in reproducing observed M-dwarf eclipsing binary radii with theoretical models are not confined to systems with very short orbital periods. This object promises to be a fruitful testing ground for the hypothesized link between inflated radii in M-dwarfs and activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/679/1490
- Title:
- Photometry and Velocity of 3 {zeta} Aur binaries
- Short Name:
- J/ApJ/679/1490
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have derived new orbits for {zeta} Aur, 32 Cyg, and 31 Cyg with observations from the Tennessee State University (TSU) Automatic Spectroscopic Telescope, and used them to identify nonorbital velocities of the cool supergiant components of these systems. Our concurrent photometry detected the nonradial pulsations driven by tides (ellipsoidal variation) in both {zeta} Aur and 32 Cyg, at a level and phasing roughly consistent with simple theory to first order, although they seem to require moderately large gravity darkening. We point out two fundamental questions in the interpretation of these stars: (1) whether it is appropriate to model the surface brightness as gravity darkening and (2) whether much of the nonorbital velocity structure may actually represent changes in the convective flows in the stars' atmospheres.
- ID:
- ivo://CDS.VizieR/J/AJ/152/161
- Title:
- Photometry for HATS-31 through HATS-35
- Short Name:
- J/AJ/152/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of five new transiting hot-Jupiter planets discovered by the HATSouth survey, HATS-31b through HATS-35b. These planets orbit moderately bright stars with V magnitudes within the range of 11.9-14.4mag while the planets span a range of masses of 0.88-1.22M_J_ and have somewhat inflated radii between 1.23 and 1.64R_J_. These planets can be classified as typical hot Jupiters, with HATS-31b and HATS-35b being moderately inflated gas giant planets with radii of 1.64+/-0.22R_J_ and 1.464_-0.044_^+0.069^R_J_, respectively, that can be used to constrain inflation mechanisms. All five systems present a higher Bayesian evidence for a fixed-circular-orbit model than for an eccentric orbit. The orbital periods range from 1.8209993+/-0.0000016 day for HATS-35b) to 3.377960+/-0.000012 day for HATS-31b. Additionally, HATS-35b orbits a relatively young F star with an age of 2.13+/-0.51Gyr. We discuss the analysis to derive the properties of these systems and compare them in the context of the sample of well-characterized transiting hot Jupiters known to date.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1832
- Title:
- Photometry in the NGC 4756 group of galaxies
- Short Name:
- J/AJ/129/1832
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of a series that focuses on investigating galaxy formation and evolution in small-scale systems of galaxies in low-density environments. We present results from a study of the NGC 4756 group, which is dominated by the elliptical galaxy NGC 4756. The characteristics of the group are investigated through (1) the detailed investigation of the morphological, photometric, and spectroscopic properties of nine galaxies among the dominant members of the group; (2) the determination of the photometric parameters of the faint galaxy population in an area of 34'x34' centered on NGC 4756; and (3) an analysis of the X-ray emission in the area based on archival data. The nine member galaxies are located in the core part of the NGC 4756 group (a strip~300kpc in diameter, H_0_=70km/s/Mpc), which has a very loose configuration. The central part of the NGC 4756 group contains a significant fraction of early-type galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/156/37
- Title:
- Photometry & Li abund. of cool dwarfs in M35
- Short Name:
- J/AJ/156/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hydra spectra of 85 G-K dwarfs in the young cluster M35 near the Li 6708 {AA} line region are analyzed. From velocities and Gaia astrometry, 78 are likely single-star members that, combined with previous work, produce 108 members with T_eff_ ranging from 6150 to 4000 K as defined by multicolor, broadband photometry, E(B-V)=0.20, and [Fe/H]=-0.15, though there are indications the metallicity may be closer to solar. The Lithium abundance A(Li) follows a well-delineated decline from 3.15 for the hottest stars to upper limits =<1.0 among the coolest dwarfs. Contrary to earlier work, M35 includes single stars at systematically higher A(Li) than the mean cluster relation. This subset exhibits higher V_ROT_ than the more Li-depleted sample and, from photometric rotation periods, is dominated by stars classed as convective (C); all others are interface (I) stars. The cool, high-Li rapid rotators (RRs) are consistent with models that simultaneously consider rapid rotation and radius inflation; RRs hotter than the Sun exhibit excess Li depletion, as predicted by the models. The A(Li) distribution with color and rotation period, when compared to the Hyades/Praesepe and the Pleiades, is consistent with gyrochronological analysis placing M35's age between the older M34 and younger Pleiades. However, the Pleiades display a more excessive range in A(Li) and rotation period than M35 on the low-Li, slow-rotation side of the distribution, with supposedly younger stars at a given T_eff_ in the Pleiades spinning slower, with A(Li) reduced by more than a factor of four compared to M35.
