- ID:
- ivo://CDS.VizieR/J/A+A/642/A93
- Title:
- EP Aqr ALMA and SPHERE observations
- Short Name:
- J/A+A/642/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cool evolved stars are known to be significant contributors to the enrichment of the interstellar medium through their dense and dusty stellar winds. High resolution observations of these outflows have shown them to possess high degrees of morphological complexity. We observed the asymptotic giant branch (AGB) star EP Aquarii with ALMA in band 6 and VLT/SPHERE/ZIMPOL in four filters the visible. Both instruments had an angular resolution of 0.025". These are follow-up observations to the lower-resolution 2016 ALMA analysis of EP Aquarii, which revealed that its wind possesses a nearly face-on, spiral-harbouring equatorial density enhancement, with a nearly pole-on bi-conical outflow. At the base of the spiral, the SiO emission revealed a distinct emission void approximately 0.4" to the west of the continuum brightness peak, which was proposed to be linked to the presence of a companion. The new ALMA data better resolve the inner wind and reveal that its morphology as observed in CO is consistent with hydrodynamical companion-induced perturbations. Assuming that photodissociation by the UV-field of the companion is responsible for the emission void in SiO, we deduced the spectral properties of the tentative companion from the size of the hole. We conclude that the most probable companion candidate is a white dwarf with a mass between 0.65 and 0.8M_{sun}_, though a solar-like companion could not be definitively excluded. The radial SiO emission shows periodic, low-amplitude perturbations. We tentatively propose that they could be the consequence of the interaction of the AGB wind with another much closer low-mass companion. The polarised SPHERE/ZIMPOL data show a circular signal surrounding the AGB star with a radius of ~0.1". Decreased signal along a PA of 138{deg} suggests that the dust is confined to an inclined ring-like structure, consistent with the previously determined wind morphology.
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Search Results
- ID:
- ivo://CDS.VizieR/VI/88
- Title:
- Ephemerides of Pluto (PLUTO95)
- Short Name:
- VI/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pluto's motion has been represented with series resulting of an approximation by frequency analysis (see Chapront 1995) of JPL numerical integration DE200. Series represent the heliocentric coordinates of Pluto as functions of time between 1700 and 2100. This catalog completes the VSOP87 theories developed at the Bureau des Longitudes (see Cat. <VI/81>)
- ID:
- ivo://CDS.VizieR/J/AcA/54/207
- Title:
- Ephemerids of eclipsing binaries
- Short Name:
- J/AcA/54/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- About 1800 O-C diagrams of eclipsing binaries were considered and up-to-date linear elements were computed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/380/1599
- Title:
- Ephemeris of V382 Cyg and TU Mus
- Short Name:
- J/MNRAS/380/1599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Up to now, V382 Cyg and TU Mus are the only two discovered O-type overcontact binary stars with periods less than two days (P=1.8855 and 1.3873d). Both systems contain a visual companion. New eclipse times and analyses of orbital period variations of the two systems are presented. It is discovered that the periods of both binaries show cyclic oscillations with periods of 47.70 and 47.73yr, while they undergo continuous increases at rates of dP/dt=+4.4x10^-7^ and +4.0x10^-7^d/yr, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A64
- Title:
- EPIC 212036875b griz light curves
- Short Name:
- J/A+A/628/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although more than 2000 brown dwarfs have been detected to date, mainly from direct imaging, their characterisation is difficult due to their faintness and model dependent results. In the case of transiting brown dwarfs it is, however, possible to make direct high precision observations. Our aim is to investigate the nature and formation of brown dwarfs by adding a new well-characterised object, in term of its mass, radius and bulk density, to the currently small sample of less than 20 transiting brown dwarfs. One brown dwarf candidate was found by the KESPRINT consortium when searching for exoplanets in the K2 space mission Campaign 16 field. We combined the K2 photometric data with a series of multi-colour photometric observations, imaging and radial velocity measurements to rule out false positive scenarios and to determine the fundamental properties of the system. We report the discovery and characterisation of a transiting brown dwarf in a 5.17 day eccentric orbit around the slightly evolved F7V star EPIC 212036875. EPIC 212036875b is a rare object that resides in the brown dwarf desert. In the mass-density diagram for planets, brown dwarfs and stars, we find that all giant planets and brown dwarfs follow the same trend from 0.3M_J_ to the turn-over to hydrogen burning stars at 73M_J_. EPIC 212036875b falls on the theoretical line for H/He dominated planets in this diagram as determined by interior structure models, as well as on the empirical fit. We argue that EPIC 212036875b formed via gravitational disc instabilities in the outer part of the disc, followed by a quick migration. Orbital tidal circularisation may have started early in its history for a brief period when the brown dwarf's radius was larger. The lack of spin-orbit synchronisation points to a weak stellar dissipation parameter which implies a circularisation timescale of 23Gyr, or suggests an interaction between the magnetic and tidal forces of the star and the brown dwarf.
- ID:
- ivo://org.gavo.dc/mpc/q/epn_core
- Title:
- EPN-TAP table for MPC Asteroid Orbital Data
- Short Name:
- MPC asteroids
- Date:
- 15 Aug 2024 15:17:04
- Publisher:
- The GAVO DC team
- Description:
- The EPN-TAP 2.0 version of the complete asteroid data from the Minor Planet Center (MPC), updated once per month. The MPC operates at the Smithsonian Astrophysical Observatory under the auspices of Division III of the International Astronomical Union (IAU). The MPC Orbit database contains orbital elements of minor planets that have been published in the Minor Planet Circulars, the Minor Planet Orbit Supplement and the Minor Planet Electronic Circulars.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A43
- Title:
- EPOCH Project. EROS-2 LMC periodic variables
- Short Name:
- J/A+A/566/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The EPOCH (EROS-2 periodic variable star classification using machine learning) project aims to detect periodic variable stars in the EROS-2 light curve database. In order to classify these variables, we first build a training set by compiling known variables in the Large Magellanic Could area from the OGLE and MACHO surveys. We crossmatch these variables with the EROS-2 sources and extract 22 variability features from 28,392 light curves of the corresponding EROS-2 sources. We then use Random Forests to classify the EROS-2 sources in the training set. We design the model to separate not only Delta Scuti stars, RR Lyraes, Cepheids, eclipsing binaries and long-period variables, the "superclasses", but also their subclasses, such as RRab, RRc, RRd and RRe for RR Lyraes, and similarly for the other variable types. We apply the trained model to the entire EROS-2 LMC database containing about 29 million sources and find 117,234 periodic variable candidates. Out of these 117,234 periodic variables, 55,285 have not been discovered by either OGLE or MACHO variability studies. This set comprises 1906 Delta Scuti stars, 6,607 RR Lyraes, 638 Cepheids, 178 Type II Cepheids, 34,562 eclipsing binaries and 11,394 long-period variables.
- ID:
- ivo://CDS.VizieR/J/ApJ/881/87
- Title:
- 9 epochs spectroscopy of type I supernova SN 201iet
- Short Name:
- J/ApJ/881/87
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present optical photometry and spectroscopy of SN2016iet (=Gaia16bvd=PS17brq), an unprecedented Type I supernova (SNI) at z=0.0676 with no obvious analog in the existing literature. SN2016iet exhibits a peculiar light curve, with two roughly equal brightness peaks (~-19mag) separated by about 100 days, and a subsequent slow decline by about 5mag in 650 rest-frame days. The spectra are dominated by strong emission lines of calcium and oxygen, with a width of only 3400km/s, superposed on a strong blue continuum in the first year. There is no clear evidence for hydrogen or helium associated with the SN at any phase. The nebular spectra exhibit a ratio of L_CaII_/L_OI_~4, much larger than for core-collapse SNe and TypeI superluminous SNe. We model the light curves with several potential energy sources: radioactive decay, a central engine, and ejecta-circumstellar medium (CSM) interaction. Regardless of the model, the inferred progenitor mass near the end of its life (i.e., the CO core mass) is >~55M{sun} and potentially up to 120M{sun}, clearly placing the event in the regime of pulsational pair instability supernovae (PPISNe) or pair instability supernovae (PISNe). The models of CSM interaction provide the most consistent explanation for the light curves and spectra, and require a CSM mass of ~35M{sun} ejected in the final decade before explosion. We further find that SN2016iet is located at an unusually large projected offset (16.5kpc, 4.3 effective radii) from its low-metallicity dwarf host galaxy (Z~0.1Z{sun}, L~0.02L*, M~108.5M{sun}), supporting the interpretation of a PPISN/PISN explosion. In our final spectrum at a phase of about 770 rest-frame days we detect weak and narrow H{alpha} emission at the location of the SN, corresponding to a star formation rate of ~3x10^-4^M{sun}/yr, which is likely due to a dim underlying galaxy host or an HII region. Despite the overall consistency of the SN and its unusual environment with PPISNe and PISNe, we find that the inferred properties of SN2016iet challenge existing models of such events.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A5
- Title:
- eps CrB radial velocity curve
- Short Name:
- J/A+A/546/A5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aim is to search for and study the origin of the low-amplitude and long-periodic radial velocity (RV) variations in K giants. We present high-resolution RV measurements of K2 giant epsilon CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Astronomy Observatory (BOAO). We find that the RV measurements for epsilon CrB exhibit a periodic variation of 417.9+/-0.5days with a semi-amplitude of 129.4+/-2.0m/s. There is no correlation between RV measurements and chromospheric activity in the Ca II H region, the Hipparcos photometry, or bisector velocity span. Keplerian motion is the most likely explanation, with the RV variations arising from an orbital motion. Assuming a possible stellar mass of 1.7+/-0.1M_{sun}_ for epsilon CrB, we obtain a minimum mass for the planetary companion of 6.7+/-0.3M_Jup_ with an orbital semi-major axis of 1.3AU and eccentricity of 0.11. We also discuss the implications of our observations for stellar metallicity versus planet occurrence rate and stellar mass versus planetary mass relations.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A91
- Title:
- {epsilon} Aur visibility measurements
- Short Name:
- J/A+A/544/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The enigmatic binary, epsilon Aurigae, is yielding its parameters as a result of new methods applied to the recent eclipse, including optical spectro-interferometry with the VEGA beam combiner at the CHARA Array. VEGA/CHARA visibility measurements from 2009 to 2011 indicate the formation of emission wings of Halpha in an expanding zone almost twice the photospheric size of the F star, namely, in a stellar wind. These may be caused by shocks in the atmosphere from large scale convective or multi-periodic pulsation modes emerging from the star. During the total eclipse phase in 2010, when the disk was in the line of sight, we saw broadening of the Halpha absorption and a less steep drop of the visibility curve, consistent with the addition of neutral hydrogen in the line of sight but extended above and below the plane of the interferometrically imaged disk itself. This provides a unique constraint on the scale height of the gaseous component of the disk material, and, based on some additional assumptions, points to a mass of the central object being 2.4 to 5.5M_{sun}_ for a distance of 650pc or 3.8 to 9.1M_{sun}_ for a distance of 1050pc. These results can be tested during coming observing seasons as the star moves from eclipse phase toward quadrature.