Search

Detached eclipsing binaries (DEBs) allow for the possibility of precise characterization of its stellar components. They offer a unique opportunity to derive their physical parameters in a near-model-independent way for a number of systems consisting of late-type giant stars. Here we aim to expand the sample of low-metallicity late-type giant stars with precise parameters determined. We aim to determine the fundamental parameters like the mass, radius, or effective temperature for three long-period late-type eclipsing binaries from the Large Magellanic Cloud: OGLE-LMC-ECL-25304, OGLE-LMC-ECL-28283, and OGLE-IV LMC554.19.81. Subsequently we aim to determine the evolutionary stages of the systems. We fit the light curves from the OGLE project and radial velocity curves from high resolution spectrographs using the Wilson-Devinney code. The spectral analysis was performed with the GSSP code and resulted in the determination of atmospheric parameters such as effective temperatures and metallicities. We used isochrones provided by the MIST models based on the MESA code to derive evolutionary status of the stars. We present the first analysis of three DEBs composed of similar He-burning late-type stars passing through the blue loop. Estimated masses for OGLE-LMC-ECL-29293 (G4III + G4III) are $M_1=2.898\pm0.031$ and $M_2=3.153\pm0.038$ $M_\odot$, stellar radii are $R_1=19.43\pm0.31$ and $R_2=19.30\pm0.31$ $R_\odot$. OGLE-LMC-ECL-25304 (G4III + G5III) has stellar masses of $M_1=3.267\pm0.028$ and $M_2=3.229\pm0.029$ $M_\odot$, radii of $R_1=23.62\pm0.42$ and $R_2=25.10\pm0.43$ $R_\odot$. OGLE-IV LMC554.19.81 (G2III + G2III) have masses of $M_1=3.165\pm0.020$ and $M_2=3.184\pm0.020$ $M_\odot$, radii of $R_1=18.86\pm0.26$ and $R_2=19.64\pm0.26$ $R_\odot$. All masses were determined with a precision better than 2\% and radii better than 1.5\%. The ages of the stars are in the range of 270-341 Myr., Comment: 15 pages, 15 figures. Accepted for publication in A&A

We resolve the multiple images of the binary-lens microlensing event ASASSN-22av using the GRAVITY instrument of the Very Large Telescope Interferometer (VLTI). The light curves show weak binary perturbations, complicating the analysis, but the joint modeling with the VLTI data breaks several degeneracies, arriving at a strongly favored solution. Thanks to precise measurements of angular Einstein radius \theta_E = 0.724 +/- 0.002 mas and microlens parallax, we determine that the lens system consists of two M dwarfs with masses of M_1 = 0.258 +/- 0.008 M_sun and M_2 = 0.130 +/- 0.007 M_sun, a projected separation of r_\perp = 6.83 +/- 0.31 AU and a distance of D_L = 2.29 +/- 0.08 kpc. The successful VLTI observations of ASASSN-22av open up a new path for studying intermediate-separation (i.e., a few AUs) stellar-mass binaries, including those containing dark compact objects such as neutron stars and stellar-mass black holes., Comment: Accepted by ApJ. See the ancillary file for animation associated with Fig. 8

We report the spectroscopic confirmation and fundamental properties of TOI-757 b, a mini-Neptune on a 17.5-day orbit transiting a bright star ($V = 9.7$ mag) discovered by the TESS mission. We acquired high-precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space-borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground-based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI-757 b has a radius of $R_{\mathrm{p}} = 2.5 \pm 0.1 R_{\oplus}$ and a mass of $M_{\mathrm{p}} = 10.5^{+2.2}_{-2.1} M_{\oplus}$, implying a bulk density of $\rho_{\text{p}} = 3.6 \pm 0.8$ g cm$^{-3}$. Our internal composition modeling was unable to constrain the composition of TOI-757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with $e$ = 0.39$^{+0.08}_{-0.07}$, making it one of the very few highly eccentric planets among precisely characterized mini-Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI-757 b's formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star-star interactions during the earlier epoch of the Galactic disk formation, given the low metallicity and older age of TOI-757., Comment: Accepted for publication in MNRAS; 26 pages, 14 figures, 6 tables

We present the results from a complex study of an eclipsing O-type binary (Aa+Ab) with the orbital period $P_{A}=3.2254367$ days, that forms part of a higher-order multiple system in a configuration (A+B)+C. We derived masses of the Aa+Ab binary $M_{1}= 19.02 \pm 0.12 \,M_\odot$, $M_{2}= 17.50 \pm 0.13 \,M_\odot$, radii $R_{1}= 7.70 \pm 0.05 \,R_\odot$, $R_{2}= 6.64 \pm 0.06 \,R_\odot$, and temperatures $T_1 = 34250 \pm 500 $ K, $T_2 = 33750 \pm 500 $ K. From the analysis of radial velocities, we found a spectroscopic orbit of A in the outer A+B system with $P_{A+B}=195.8$ days ($P_{A+B}/P_{A}\approx 61$). In the O-C analysis, we confirmed this orbit and found another component orbiting the A+B system with $P_{AB+C}=2550$ days ($P_{AB+C}\,/P_{A+B}\approx 13$). From the total mass of the inner binary and its outer orbit, we estimated the mass of the third object, $M_B \gtrsim 10.7 M_\odot$. From the light-travel time effect fit to the O-C data, we obtained the limit for the mass of the fourth component, $M_C \gtrsim 7.3 M_\odot$. These extra components contribute to about 20% to 30% (increasing with wavelength) of the total system light. From the comparison of model spectra with the multiband photometry, we derived a distance modulus of 18.59 $\pm$ 0.06 mag, a reddening of 0.16 $\pm$ 0.02 mag, and an $R_V$ of $3.2$. This work is part of our ongoing project, which aims to calibrate the surface brightness-color relation for early-type stars., Comment: 15 pages, 14 figures, 3 tables, accepted for publication in The Astrophysical Journal

Context: Carbon Enhanced Metal-Poor (CEMP) stars ($\mathrm{[C/Fe]} > 0.7$) are known to exist in large numbers at low metallicity in the Milky Way halo and are important tracers of early Galactic chemical evolution. However, very few such stars have been identified in the classical dwarf spheroidal (dSph) galaxies, and detailed abundances, including neutron-capture element abundances, have only been reported for 12 stars. Aims: We aim to derive detailed abundances of six CEMP stars identified in the Carina dSph and compare the abundances to CEMP stars in other dSph galaxies and the Milky Way halo. This is the largest sample of CEMP stars in a dSph galaxy analysed to date. Methods: 1D LTE elemental abundances are derived via equivalent width and spectral synthesis using high-resolution spectra of the six stars obtained with the MIKE spectrograph at Las Campanas Observatory. Results: Abundances or upper limits are derived for up to 27 elements from C to Os in the six stars. The analysis reveals one of the stars to be a CEMP-no star with very low neutron-capture element abundances. In contrast, the other five stars all show enhancements in neutron-capture elements in addition to their carbon enhancement, classifying them as CEMP-$s$ and -$r/s$ stars. The six stars have similar $\alpha$ and iron-peak element abundances as other stars in Carina, except for the CEMP-no star, which shows enhancement in Na, Mg, and Si. We explore the absolute carbon abundances ($A(\rm C)$) of CEMP stars in dSph galaxies and find similar behaviour as is seen for Milky Way halo CEMP stars, but highlight that CEMP-$r/s$ stars primarily have very high $A(\rm C)$ values. We also compare the neutron-capture element abundances of the CEMP-$r/s$ stars in our sample to recent $i$-process yields, which provide a good match to the derived abundances., Comment: 14 pages, 5 figures, 9 tables, Accepted for publication in A&A

Our goal is to determine, with high accuracy, the physical and orbital parameters of two double-lined eclipsing binary systems, where the components are two giant stars. We also aim to study the evolutionary status of the binaries, to derive the distances towards them by using a surface brightness-colour relation, and to compare these measurements with the measurements presented by the Gaia mission. In order to measure the physical and orbital parameters of the systems, we analysed the light curves and radial-velocity curves with the Wilson-Devinney code. We used V band and I-band photometry from the OGLE catalogue and near-infrared photometry obtained with the New Technology Telescope (NTT) equipped with the SOFI instrument. The spectroscopic data were collected with the HARPS spectrograph mounted at the ESO 3.6m telescope and the MIKE spectrograph mounted at the 6.5m Clay telescope. We present the first analysis of this kind for two evolved eclipsing binary systems from the OGLE catalogue: OGLE-BLG-ECL-305487 and OGLE-BLG-ECL-116218. The masses of the components of OGLE-BLG-ECL-305487 are $M_1$ = 1.059 $\pm$ 0.019 and $M_2$ = 0.991 $\pm$ 0.018 $M_\odot$, and the radii are $R_1$ = 19.27 $\pm$ 0.28 and $R_2$ = 29.99 $\pm$ 0.24 R$_\odot$. For OGLE-BLG-ECL-116218, the masses are $M_1$= 0.969 $\pm$ 0.012 and $M_2$= 0.983 $\pm$ 0.012 $M_\odot$, while the radii are $R_1$= 16.73 $\pm$ 0.28 and $R_2$= 22.06 $\pm$ 0.26 $R_\odot$. The evolutionary status of the systems is discussed based on the PARSEC and MIST isochrones. The ages of the systems were established to be between 7.3-10.9 Gyr for OGLE-BLG-ECL-305487 and around 10 Gyr for OGLE-BLG-ECL-116218. We also measured the distances to the binaries. For OGLE-BLG-ECL-305487, $d$= 7.80 $\pm$ 0.18 (stat.) $\pm$ 0.19 (syst.) kpc and for OGLE-BLG-ECL-116218, $d$= 7.57 $\pm$ 0.28 (stat.) $\pm$ 0.19 (syst.) kpc., Comment: 12 pages, 5 figures, accepted in A&A

We review recent progress and motivate the need for further developments in nuclear optical potentials that are widely used in the theoretical analysis of nucleon elastic scattering and reaction cross sections. In regions of the nuclear chart away from stability, which represent a frontier in nuclear science over the coming decade and which will be probed at new rare-isotope beam facilities worldwide, there is a targeted need to quantify and reduce theoretical reaction model uncertainties, especially with respect to nuclear optical potentials. We first describe the primary physics motivations for an improved description of nuclear reactions involving short-lived isotopes, focusing on its benefits for fundamental science discoveries and applications to medicine, energy, and security. We then outline the various methods in use today to build optical potentials starting from phenomenological, microscopic, and ab initio methods, highlighting in particular the strengths and weaknesses of each approach. We then discuss publicly-available tools and resources facilitating the propagation of recent progresses in the field to practitioners. Finally, we provide a set of open challenges and recommendations for the field to advance the fundamental science goals of nuclear reaction studies in the rare-isotope beam era., Comment: This paper is the outcome of the Facility for Rare Isotope Beams Theory Alliance (FRIB - TA) topical program "Optical Potentials in Nuclear Physics" held in March 2022 at FRIB. Its content is non-exhaustive, was chosen by the participants and reflects their efforts related to optical potentials

A measurement of proton inelastic scattering of $^8$He at $8.25A$~MeV at TRIUMF shows a resonance at 3.54(6)~MeV with a width of 0.89(11)~MeV. The energy of the state is in good agreement with coupled cluster and no-core shell model with continuum calculations, with the latter successfully describing the measured resonance width as well. Its differential cross section analyzed with phenomenological collective excitation form factor and microscopic coupled reaction channels framework consistently reveals a large deformation parameter $\beta_2$ = 0.40(3), consistent with no-core shell model predictions of a large neutron deformation. This deformed double-closed shell at the neutron drip-line opens a new paradigm., Comment: 9 pages, 5 figures. Accepted for publication in Physics Letters B

We characterize the extreme heartbeat star system MACHO 80.7443.1718 in the LMC using TESS photometry and spectroscopic observations from the Magellan Inamori Kyocera Echelle (MIKE) and SOAR Goodman spectographs. MACHO 80.7443.1718 was first identified as a heartbeat star system in the All-Sky Automated Survey for SuperNovae (ASAS-SN) with $P_{\rm orb}=32.836\pm0.008\,{\rm d}$. MACHO 80.7443.1718 is a young (${\sim}6$~Myr), massive binary, composed of a B0 Iae supergiant with $M_1 \simeq 35 M_\odot$ and an O9.5V secondary with $M_2 \simeq 16 M_\odot$ on an eccentric ($e=0.51\pm0.03$) orbit. In addition to having the largest variability amplitude amongst all known heartbeats stars, MACHO 80.7443.1718 is also one of the most massive heartbeat stars yet discovered. The B[e] supergiant has Balmer emission lines and permitted/forbidden metallic emission lines associated with a circumstellar disk. The disk rapidly dissipates at periastron which could indicate mass transfer to the secondary, but re-emerges immediately following periastron passage. MACHO 80.7443.1718 also shows tidally excited oscillations at the $N=25$ and $N=41$ orbital harmonics and has a rotational period of 4.4 d., Comment: 21 pages, 16 figures. Submitted to MNRAS

We report the discovery of two transiting Neptunes by the HATSouth survey. The planet HATS-37Ab has a mass of 0.099 +- 0.042 M_J (31.5 +- 13.4 M_earth) and a radius of 0.606 +- 0.016 R_J, and is on a P = 4.3315 days orbit around a V = 12.266 mag, 0.843 M_sun star with a radius of 0.877 R_sun. We also present evidence that the star HATS-37A has an unresolved stellar companion HATS-37B, with a photometrically estimated mass of 0.654 M_sun.The planet HATS-38b has a mass of 0.074 +- 0.011 M_J (23.5 +- 3.5 M_earth) and a radius of 0.614 +- 0.017 R_J, and is on a P = 4.3750 days orbit around a V = 12.411 mag, 0.890 M_sun star with a radius of 1.105 R_sun. Both systems appear to be old, with isochrone-based ages of 11.46 +0.79-1.45 Gyr, and 11.89 +- 0.60 Gyr, respectively. Both HATS-37Ab and HATS-38b lie in the Neptune desert and are thus examples of a population with a low occurrence rate. They are also among the lowest mass planets found from ground-based wide-field surveys to date., Comment: Accepted for publication in the Astronomical Journal

The field of the globular cluster M10 (NGC 6254) was monitored between 1998 and 2015 in a search for variable stars. V -light curves were derived for 40 variables or likely variables, most of which are new detections. Proper motions obtained within the CASE project indicate that 18 newly detected variables and 14 previously known ones are members or likely members of the cluster, including one RRc-type, three type II Cepheids, and 14 SX Phe-type pulsators, one contact binary, and six semi-regular red giants. As a byproduct of the search we discovered a candidate binary comprised of main sequence stars with the record-short orbital period of 0.042 d. We also confirmed the photometric variability of the red straggler M10-VLA1 hinted at by Shishkovsky et al. (2018), who discovered this object spectroscopically. In Appendix 1 we show that CASE proper motion measurements are in a good agreement with those retrieved from the Gaia archive, while Appendix 2 presents evidence for low frequency {\gamma} Doradus-type oscillations in SX Phe stars belonging to M10.

We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain Mp = 0.862(5) Msun , Rp = 1.183(3) Rsun , Lp = 1.65(5) Lsun for the primary and Ms = 0.827(5) Msun , Rs = 1.004(4) Rsun , Ls = 1.14(4) Lsun for the secondary. Based on these data and on an earlier analysis of the binary V69 in 47 Tuc we measure the distance to the cluster from the distance moduli of the component stars, and, independently, from a color - surface brightness calibration. We obtain 4.55(3) and 4.50(7) kpc, respectively - values compatible within 1 sigma with recent estimates based on Gaia DR2 parallaxes. By comparing the M - R diagram of the two binaries and the color-magnitude diagram of 47 Tuc to Dartmouth model isochrones we estimate the age of the cluster to be 12.0 pm 0.5 Gyr, and the helium abundance of the cluster to be Y approx 0.25., Comment: Accepted by MNRAS

DS Tuc Ab is a Neptune-sized planet that orbits around a member of the 45 Myr old Tucana-Horologium moving group. Here, we report the measurement of the sky-projected angle between the stellar spin axis and the planet's orbital axis, based on the observation of the Rossiter-McLaughlin effect during three separate planetary transits. The orbit appears to be well aligned with the equator of the host star, with a projected obliquity of lambda = 2.5 +1.0/-0.9 deg. In addition to the distortions in the stellar absorption lines due to the transiting planet, we observed variations that we attribute to large starspots, with angular sizes of tens of degrees. The technique we have developed for simultaneous modeling of starspots and the planet-induced distortions may be useful in other observations of planets around active stars., Comment: Accepted by ApJL

In this first paper of the series we describe our project to calibrate the distance determination method based on early-type binary systems. The final objective is to measure accurate, geometrical distances to galaxies beyond the Magellanic Clouds with a precision of 2%. We start with the analysis of two early-type systems for which we have collected all the required spectroscopic and photometric data. Apart from catalog publications, these systems have not been studied yet, and it is the first time the modeling of light and radial velocity curves is performed for them. From the analysis we obtained precise physical parameters of the components, including the masses measured with precision of 0.6-1% and radii with precision of 0.4-3%. For one system we determined the $(V-K)$ color and estimated the distance using the bolometric flux scaling method (DM=18.47 $\pm$ 0.15 mag), which agrees well with our accurate determination of the distance to the LMC from late-type giants. For the same system we determined the surface brightness of individual stars using our model, and checked that it is consistent with a recent surface brightness -- color relation. We compared our results with evolution theory models of massive stars and found they agree in general, however, models with higher overshooting values give more consistent results. The age of the system was estimated to from 11.7 to 13.8 Myr, depending on the model., Comment: 17 pages, 14 figures, 4 tables, Accepted for publication in ApJ

The most abundant stars in the Galaxy, M dwarfs, are very commonly hosts to diverse systems of low-mass planets. Their abundancy implies that the general occurrence rate of planets is dominated by their occurrence rate around such M dwarfs. In this article, we combine the M dwarf surveys conducted with the HIRES/Keck, PFS/Magellan, HARPS/ESO, and UVES/VLT instruments supported with data from several other instruments. We analyse the radial velocities of an approximately volume- and brightness-limited sample of 426 nearby M dwarfs in order to search for Doppler signals of cadidate planets. In addition, we analyse spectroscopic activity indicators and ASAS photometry to rule out radial velocity signals corresponding to stellar activity as Doppler signals of planets. We calculate estimates for the occurrence rate of planets around the sample stars and study the properties of this occurrence rate as a function of stellar properties. Our analyses reveal a total of 118 candidate planets orbiting nearby M dwarfs. Based on our results accounting for selection effects and sample detection threshold, we estimate that M dwarfs have on average at least 2.39$^{+4.58}_{-1.36}$ planets per star orbiting them. Accounting for the different sensitivities of radial velocity surveys and Kepler transit photometry implies that there are at least 3.0 planets per star orbiting M dwarfs. We also present evidence for a population of cool mini-Neptunes and Neptunes with indications that they are found an order of magnitude more frequently orbiting the least massive M dwarfs in our sample., Comment: Manuscript submitted to AAS journals. 338 pages, including 66 pages of tables summarising data properties, target properties, and selected parameter estimates

Aim: Our aim is to obtain high-accuracy measurements of the physical and orbital parameters of two evolved eclipsing binary systems, and to use these measurements to study their evolutionary status. We also aim to derive distances to the systems by using a surface brightness - colour relation and compare these distances with the measurements provided by GAIA. Methods: We measured the physical and orbital parameters on both systems based on V-band and I-band photometry from OGLE, near-infrared photometry obtained with the NTT telescope and the instrument SOFI, as well as high-resolution spectra obtained at ESO 3.6m/HARPS and Clay 6.5/MIKE spectrographs. The light curves and radial-velocity curves were analysed with the Wilson-Devinney code. Results: We analysed two double-lined eclipsing binary systems OGLE-BLG-ECL-23903 and OGLE-BLG-ECL-296596 from the Optical Gravitational Lensing Experiment (OGLE) catalogue. Both systems have a configuration of two well-detached giant stars. The masses of the components ofOGLE-BLG-ECL-123903 are M_1= 2.045 $\pm$ 0.027 and M_2=2.074 $\pm$ 0.023 $M_\odot$ and the radii are R_1=9.540 $\pm$ 0.049 and R_2=9.052 $\pm$ 0.060 $R_\odot$. For OGLE-BLG-ECL-296596, the masses are M_1=1.093 $\pm$ 0.015 and M_2=1.125 $\pm$ 0.014 $M_\odot$, while the radii are R_1=18.06 $\pm$ 0.28 and R_2=29.80 $\pm$ 0.33 $R_\odot$. Evolutionary status was discussed based on the isochrones and evolutionary tracks from PARSEC and MESA codes. The ages of the systems were establishes to be around 1.3 Gyr for the OGLE-BLG-ECL-123903 and 7.7 Gyr for the OGLE-BLG-ECL-296596. We also determined the distance to both systems. For OGLE-BLG-ECL-123903 this is equal to d=2.95 $\pm$ 0.06 (stat.) $\pm$ 0.07 (syst.) kpc, while for the OGLE-BLG-ECL-296596 it is d=5.68 $\pm$ 0.07 (stat.) $\pm$ 0.14 (syst.) kpc. This is the first analysis of its kind for these unique evolved eclipsing binary systems., Comment: 11 pages, 6 figures

In the era of precision cosmology, it is essential to empirically determine the Hubble constant with an accuracy of one per cent or better. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period - luminosity relationship (also known as Leavitt Law). The Large Magellanic Cloud has traditionally served as the best galaxy with which to calibrate Cepheid period-luminosity relations, and as a result has become the best anchor point for the cosmic distance scale. Eclipsing binary systems composed of late-type stars offer the most precise and accurate way to measure the distance to the Large Magellanic Cloud. Currently the limit of the precision attainable with this technique is about two per cent, and is set by the precision of the existing calibrations of the surface brightness - colour relation. Here we report the calibration of the surface brightness-colour relation with a precision of 0.8 per cent. We use this calibration to determine the geometrical distance to the Large Magellanic Cloud that is precise to 1 per cent based on 20 eclipsing binary systems. The final distane is 49.59 +/- 0.09 (statistical) +/- 0.54 (systematic) kiloparsecs., Comment: Published in Nature 567, 200 (2019)

The exotic Borromean nucleus $^{20}$Mg with $N$ = 8, located at the proton drip-line provides a unique testing ground for nuclear forces and the evolution of shell structure in the neutron-deficient region. We report on the first observation of proton unbound resonances together with bound states in $^{20}$Mg from the $^{20}$Mg($d$,$d'$) reaction performed at TRIUMF. Phenomenological shell-model calculations offer a reasonable description. However, our experimental results present a challenge for current first-principles nuclear structure approaches and point to the need for improved chiral forces and {\it ab initio} calculations. Furthermore, the differential cross section of the first excited state is compared with distorted-wave Born approximation calculations to deduce a neutron quadrupole deformation parameter of $\beta_n$=0.46$\pm$0.21. This provides the first indication of a possible weakening of the $N$ = 8 shell closure at the proton drip-line., Comment: 6 pages, 4 figures

The extragalactic distance scale builds on the Cepheid period-luminosity (PL) relation. In this paper, we want to carry out a strictly differential comparison of the absolute PL relations obeyed by classical Cepheids in the Milky Way (MW), LMC and SMC galaxies. Taking advantage of the substantial metallicity difference among the Cepheid populations in these three galaxies, we want to establish a possible systematic trend of the PL relation absolute zero point as a function of metallicity, and determine the size of such an effect in optical and near-infrared photometric bands. We are using the IRSB Baade-Wesselink type method as calibrated by Storm et al. to determine individual distances to the Cepheids in our samples in MW, LMC and SMC. For our analysis, we use a greatly enhanced sample of Cepheids in the SMC (31 stars) as compared to the small sample (5 stars) available in our previous work. We use the distances to determine absolute Cepheid PL relations in optical and near-infrared bands in each of the three galaxies.} {Our distance analysis of 31 SMC Cepheids with periods from 4-69 days yields tight PL relations in all studied bands, with slopes consistent with the corresponding LMC and MW relations. Adopting the very accurately determined LMC slopes for the optical and near-infrared bands, we determine the zero point offsets between the corresponding absolute PL relations in the 3 galaxies. We find that in all bands the metal-poor SMC Cepheids are intrinsically fainter than their more metal-rich counterparts in the LMC and MW. In the $K$ band the metallicity effect is $-0.23\pm0.06$~mag/dex while in the $V,(V-I)$ Wesenheit index it is slightly stronger, $-0.34\pm0.06$~mag/dex. We find some evidence that the PL relation zero point-metallicity relation might be nonlinear, becoming steeper for lower metallicities., Comment: 20 pages, accepted for publication by A&A

We report the discovery of ten transiting extrasolar planets by the HATSouth survey. The planets range in mass from the Super-Neptune HATS-62b, with $M_{p} < 0.179 M_{J}$, to the Super-Jupiter HATS-66b, with $M_{p} = 5.33 M_{J}$, and in size from the Saturn HATS-69b, with $R_{p} = 0.94 R_{J}$, to the inflated Jupiter HATS-67b, with $R_{p} = 1.69 R_{J}$. The planets have orbital periods between 1.6092 days (HATS-67b) and 7.8180 days (HATS-61b). The hosts are dwarf stars with masses ranging from $0.89 M_{\odot}$ (HATS-69) to $1.56 M_{\odot}$ (HATS-64), and have apparent magnitudes between $V = 12.276 \pm 0.020$ mag (HATS-68) and $V = 14.095 \pm 0.030$ mag (HATS-66). The Super-Neptune HATS-62b is the least massive planet discovered to date with a radius larger than Jupiter. Based largely on the Gaia DR2 distances and broad-band photometry, we identify three systems (HATS-62, -64, and -65) as having possible unresolved binary star companions. We discuss in detail our methods for incorporating the Gaia DR2 observations into our modeling of the system parameters, and into our blend analysis procedures., Comment: Replaced with version accepted for publication in AJ, some changes to parameter values compared to previous version, 41 pages, 12 figures, 19 Tables

We adapt the friends of friends algorithm to the analysis of light curves, and show that it can be successfully applied to searches for transient phenomena in large photometric databases. As a test case we search OGLE-III light curves for known dwarf novae. A single combination of control parameters allows to narrow the search to 1% of the data while reaching a $\sim$90% detection efficiency. A search involving $\sim$2% of the data and three combinations of control parameters can be significantly more effective - in our case a 100% efficiency is reached. The method can also quite efficiently detect semi-regular or strictly periodic variability. We report 28 new variables found in the field of the globular cluster M22, which was examined earlier with the help of periodicity-searching algorithms

The field of the globular cluster M22 (NGC 6656) was monitored between 2000 and 2008 in a search for variable stars. $BV$ light curves were obtained for 359 periodic, likely periodic, and long-term variables, 238 of which are new detections. Thirty nine newly detected variables, and 63 previously known ones are members or likely members of the cluster, including 20 SX Phe, 10 RRab and 16 RRc-type pulsators, one BL Her-type pulsator, 21 contact binaries, and 9 detached or semi-detached eclipsing binaries. The most interesting among the identified objects are V112 - a bright multimode SX Phe pulsator, V125 - a $\beta$ Lyr-type binary on the blue horizontal branch, V129 - a blue/yellow straggler with a W UMa-like light curve, located halfway between the extreme horizontal branch and red giant branch, and V134 - an extreme horizontal branch object with $P=2.33$ d and a nearly sinusoidal light curve; all four of them are proper motion (PM) members of the cluster. Among nonmembers, a $P=2.83$ d detached eclipsing binary hosting a $\delta$ Sct-type pulsator was found, and a peculiar $P=0.93$ d binary with ellipsoidal modulation and narrow minimum in the middle of one of the descending shoulders of the sinusoid. We also collected substantial new data for previously known variables; in particular we revise the statistics of the occurrence of the Blazhko effect in RR Lyr-type variables of M22., Comment: 21 pages, 8 figures, 3 tables

We report the discovery of four short period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 M$_J$, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets range from 2.7d to 4.7d, with HATS-43b having an orbit that appears to be marginally non-circular (e= 0.173$\pm$0.089). HATS-44 is notable for a high metallicity ([Fe/H]= 0.320$\pm$0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3

We derive relative proper motions of stars in the fields of the globular clusters M12, NGC 6362, M4, M55, M22, NGC 6752, NGC 3201, M30, M10, NGC 362, M5, and 47 Tucanae based on data collected between 1997 and 2015 with the 1-m Swope telescope of Las Campanas Observatory. We determine membership class and membership probability for over 446 000 objects, and show that these are efficient methods for separating field stars from members of the cluster. In particular, membership probabilities of variable stars and blue/yellow/red stragglers are determined. Finally, we find absolute proper motions for six globular clusters from our sample: M55, NGC 3201, M10, NGC 362, M5, and 47 Tuc. An electronic catalogue of the derived proper motions is publicly available via the internet., Comment: 24 pages, 35 figures, 6 tables. Accepted for publication in MNRAS. Figures of high quality on request

The Workshop on Nuclear Data Needs and Capabilities for Basic Science was held at the University of Notre Dame on 10-11 August 2016. The purpose of this targeted workshop was to assemble and prioritize the needs of the nuclear physics research community for data sets, services and capabilities in areas including nuclear structure, nuclear reactions, nuclear astrophysics, fundamental interactions, neutrino physics and nuclear theory. An overview of nuclear data needs and capabilities identified at this meeting are summarized in the present document., Comment: This white paper and copies of the presentations can be found on the meeting website at http://meetings.nscl.msu.edu/2016ND_workshop/html/home.html

Planets in the mass range from 2 to 15 MEarth are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss.We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days.Although the two planets have similar masses, their densities are very different. For K2-106b we derive Mb=8.36-0.94+0.96 MEarh, Rb=1.52+/-0.16 REarth, and a high density of 13.1-3.6+5.4 gcm-3. For K2-106c, we find Mc=5.8-3.0+3.3 MEarth, Rc=2.50-0.26+0.27 REarth and a relatively low density of 2.0-1.1+1.6 gcm-3.Since the system contains two planets of almost the same mass, but different distances from the host star, it is an excellent laboratory to study atmospheric escape. In agreement with the theory of atmospheric-loss processes, it is likely that the outer planet has a hydrogen-dominated atmosphere. The mass and radius of the inner planet is in agreement with theoretical models predicting an iron core containing 80+20-30% of its mass. Such a high metal content is surprising, particularly given that the star has an ordinary (solar) metal abundance. We discuss various possible formation scenarios for this unusual planet., Comment: 11 pages with 9 figures, accepted by A&A, Sep 8, 2017

We present the analysis of the top-quality photometry of RR Lyrae stars in the globular cluster NGC 6362, gathered over 11 observing seasons by the CASE project. 16 stars are fundamental mode pulsators (RRab stars) and 16 are first overtone pulsators (RRc stars). In two stars, previously identified as RRab, V3 and V34, we detect additional periodicity identified as radial first overtone mode. Lower than usual period ratios (0.730 and 0.728), dominant pulsation in the radial fundamental mode and presence of a long-period modulation indicate, that these two variables are not classical RRd stars, but are new members of the recently identified class of anomalous RRd variables. In a significant fraction of RRc stars, 63 per cent, we detect additional shorter-period variability in the (0.60, 0.65)$P_1$ range. This form of double-periodic pulsation must be common in first overtone RR Lyr stars, as space observations indicate. The incidence rate we find in NGC 6362, is the highest in ground-based observations reported so far. We study the properties of these stars in detail; in particular we confirm that in the colour-magnitude diagram, this group is adjacent to the interface between RRab and RRc stars, as first reported in the analysis of M3 observations by Jurcsik et al. The incidence rate of the Blazhko effect is also very high: we observe it in 69 per cent of RRab stars and in 19 per cent of RRc stars. Rare, double-periodic modulation is reported in one RRab and in one RRc star. Finally we discuss V37 - a peculiar variable in which we detect two close high-amplitude periodicities and modulation. Its previous classification as RRc must be treated as tentative., Comment: Accepted for publication in MNRAS. Three animations available as ancillary files

While diproton decay was first theorized in 1960 and first measured in 2002, it was first observed only in 2012. The measurement of $^{14}$Be in coincidence with two neutrons suggests that $^{16}$Be does decay through the simultaneous emission of two strongly correlated neutrons. In this work, we construct a full three-body model of $^{16}$Be (as $^{14}$Be + n + n) in order to investigate its configuration in the continuum and in particular the structure of its ground state. In order to describe the three-body system, effective n-$^{14}$Be potentials were constructed, constrained by the experimental information on $^{15}$Be. The hyperspherical R-matrix method was used to solve the three-body scattering problem, and the resonance energy of $^{16}$Be was extracted from a phase shift analysis. In order to reproduce the experimental resonance energy of $^{16}$Be within this three-body model, a three-body interaction was needed. For extracting the width of the ground state of $^{16}$Be, we use the full width at half maximum of the derivative of the three-body phase shifts and the width of the three-body elastic scattering cross section. Our results confirm a dineutron structure for $^{16}$Be, dependent on the internal structure of the subsystem $^{15}$Be., Comment: 13 pages, 9 figures, submitted to Phys. Rev. C

The field of the globular cluster NGC 362 was monitored between 1997 and 2015 in a search for variable stars. BV light curves were obtained for 151 periodic or likely periodic variables, over a hundred of which are new detections. Twelve newly detected variables are proper motion members of the cluster: two SX Phe and two RR Lyr pulsators, one contact binary, three detached or semi-detached eclipsing binaries, and four spotted variables. The most interesting objects among these are the binary blue straggler V20 with an asymmetric light curve, and the 8.1 d semidetached binary V24 located on the red giant branch of NGC 362, which is a Chandra X-ray source. We also provide substantial new data for 24 previously known variables., Comment: Accepted by Acta Astronomica; v.2 with a few typos corrected

We report the discovery by the HATSouth exoplanet survey of three hot-Saturn transiting exoplanets: HATS-19b, HATS-20b, and HATS-21b. The planet host HATS-19 is a slightly evolved V = 13.0 G0 star with [Fe/H] = 0.240, a mass of 1.303 Msun, and a radius of 1.75 Rsun. HATS-19b is in an eccentric orbit (e = 0.30) around this star with an orbital period of 4.5697 days and has a mass of 0.427 Mjup and a highly inflated radius of 1.66 Rjup. The planet HATS-20b has a Saturn-like mass and radius of 0.273 Mjup and 0.776 Rjup respectively. It orbits the V = 13.8 G9V star HATS-20 (Ms = 0.910 Msun; Rs = 0.892 Rsun) with a period of 3.7993 days. Finally, HATS-21 is a V = 12.2 G4V star with [Fe/H] = 0.300, a mass of 1.080 Msun, and a radius of 1.021 Rsun. Its accompanying planet HATS-21b has a 3.5544-day orbital period, a mass of 0.332 Mjup, and a moderately inflated radius of 1.123 Rjup. With the addition of these three very different planets to the growing sample of hot-Saturns, we re-examine the relations between the observed giant planet radii, stellar irradiation, and host metallicity. We find a significant positive correlation between planet equilibrium temperature and radius, and a weak negative correlation between host metallicity and radius. To assess the relative influence of various physical parameters on observed planet radii, we train and fit models using Random Forest regression. We find that for hot-Saturns (0.1 < Mp < 0.5 Mjup), the planetary mass and equilibrium temperature play dominant roles in determining radii. For hot-Jupiters (0.5 < Mp < 2.0 Mjup), the most important parameter is equilibrium temperature alone. Finally, for irradiated higher-mass planets (Mp > 2.0 Mjup), we find that equilibrium temperature dominates in influence, with smaller contributions from planet mass and host metallicity., Comment: Submitted to AAS journals. IPython notebook at https://github.com/waqasbhatti/hats19to21 and all HATSouth planet data at http://hatsouth.org

We present an analysis of a new detached eclipsing binary, OGLE-LMC-ECL-25658, in the Large Magellanic Cloud. The system consists of two late G-type giant stars on an eccentric orbit and orbital period of ~200 days. The system shows total eclipses and the components have similar temperatures, making it ideal for a precise distance determination. Using multi-color photometric and high resolution spectroscopic data, we have performed an analysis of light and radial velocity curves simultaneously using the Wilson Devinney code. We derived orbital and physical parameters of the binary with a high precision of < 1 %. The masses and surface metallicities of the components are virtually the same and equal to 2.23 +/- 0.02 M_sun and [Fe/H] = -0.63 +/- 0.10 dex. However their radii and rates of rotation show a distinct trace of differential stellar evolution. The distance to the system was calculated using an infrared calibration between V-band surface brightness and (V-K) color, leading to a distance modulus of (m-M) = 18.452 +/- 0.023 (statistical) +/- 0.046 (systematic). Because OGLE-LMC-ECL-25658 is located relatively far from the LMC barycenter we applied a geometrical correction for its position in the LMC disc using the van der Marel et al. model of the LMC. The resulting barycenter distance to the galaxy is d_LMC = 50.30 +/- 0.53 (stat.) kpc, and is in perfect agreement with the earlier result of Pietrzynski et al.(2013)., Comment: accepted for publication in the Astronomical Journal

We report trigonometric parallaxes for 134 low mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey targeted nearby targets, so 119 are closer than 30 pc. Of the 38 stars with new parallaxes, 14 are within 20 pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G 161-71 in Argus. We also report the first parallax for the planet-hosting star GJ 3470; this allows us to refine the density of its Neptune-mass planet. One T-dwarf, 2MASS J12590470-4336243, previously thought to lie within 4 pc, is found to be at 7.8 pc, and the M-type star 2MASS J01392170-3936088 joins the ranks of nearby stars as it is found to be within 10 pc. Five stars that are over-luminous and/or too red for their spectral types are identified and deserve further study as possible young stars., Comment: Accepted to AJ; two long tables

The field of the globular cluster NGC 3201 was monitored between 1998 and 2009 in a search for variable stars. $BV$ light curves were obtained for 152 periodic or likely periodic variables, 57 of which are new detections. Thirty-seven newly detected variables are proper motion members of the cluster. Among them we found seven detached or semi-detached eclipsing binaries, four contact binaries, and eight SX Phe pulsators. Four of the eclipsing binaries are located in the turnoff region, one on the lower main sequence and the remaining two slightly above the subgiant branch. Two contact systems are blue stragglers, and another two reside in the turnoff region. In the blue straggler region a total of 266 objects were found, of which 140 are proper motion (PM) members of NGC 3201, and another 19 are field stars. Seventy-eight of the remaining objects for which we do not have PM data are located within the half-light radius from the center of the cluster, and most of them are likely genuine blue stragglers. Four variable objects in our field of view were found to coincide with X-ray sources: three chromosperically active stars and a quasar at a redshift $z\approx0.5$., Comment: Accepted by Acta Astronomica

We report the discovery of HATS-15 b and HATS-16 b, two massive transiting extrasolar planets orbiting evolved ($\sim 10$ Gyr) main-sequence stars. The planet HATS-15 b, which is hosted by a G9V star ($V=14.8$ mag), is a hot Jupiter with mass of $2.17\pm0.15\, M_{\mathrm{J}}$ and radius of $1.105\pm0.0.040\, R_{\mathrm{J}}$, and completes its orbit in nearly 1.7 days. HATS-16 b is a very massive hot Jupiter with mass of $3.27\pm0.19\, M_{\mathrm{J}}$ and radius of $1.30\pm0.15\, R_{\mathrm{J}}$; it orbits around its G3 V parent star ($V=13.8$ mag) in $\sim2.7$ days. HATS-16 is slightly active and shows a periodic photometric modulation, implying a rotational period of 12 days which is unexpectedly short given its isochronal age. This fast rotation might be the result of the tidal interaction between the star and its planet., Comment: 16 pages, 8 figures, submitted to PASP