- ID:
- ivo://CDS.VizieR/J/A+AS/122/515
- Title:
- HL Aur light curves and minima
- Short Name:
- J/A+AS/122/515
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric observations of HL Aur were carried out with the 60cm reflector of Beijing Astronomical Observatory in 1990 and 1994, and the first photoelectric BV light curves were obtained along with a newly derived ephemeris. The period of the system appears to be constant over the past 65-years. Using the Wilson-Devinney program a photometric analysis of the B and V light curves is performed. It is evident that HL Aur is a near-contact binary with a mass ratio of q=m_2_/m_1_=0.722+/-0.011. The primary component of the system is essentially in contact with its Roche lobe, while the secondary is detached but nearly in contact with its lobe. It is found that the components of the system are slightly evolved and located near the terminal-age main sequence. The binary is consistent with the general evolutionary picture for near-contact systems.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1118
- Title:
- HU Aqr planetary system mid-egress moments
- Short Name:
- J/MNRAS/448/1118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the mid-egress eclipse timing data gathered for the cataclysmic binary HU Aquarii during the years 1993-2014. The (O-C) residuals were previously attributed to a single ~7 Jupiter mass companion in ~5 AU orbit or to a stable two-planet system with an unconstrained outermost orbit. We present 22 new observations gathered between 2011 June and 2014 July with four instruments around the world. They reveal a systematic deviation of ~60-120 s from the older ephemeris. We re-analyse the whole set of the timing data available. Our results provide an erratum to the previous HU Aqr planetary models, indicating that the hypothesis for a third and fourth body in this system is uncertain. The dynamical stability criterion and a particular geometry of orbits rule out coplanar two-planet configurations. A putative HU Aqr planetary system may be more complex, e.g. highly non-coplanar. Indeed, we found examples of three-planet configurations with the middle planet in a retrograde orbit, which are stable for at least 1 Gyr, and consistent with the observations. The (O-C) may be also driven by oscillations of the gravitational quadrupole moment of the secondary, as predicted by the Lanza et al. modification of the Applegate mechanism. Further systematic, long-term monitoring of HU Aqr is required to interpret the (O-C) residuals.
- ID:
- ivo://CDS.VizieR/J/AJ/154/162
- Title:
- KMTNet-SAAO observation of near-Earth asteroids
- Short Name:
- J/AJ/154/162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here VRI spectrophotometry of 39 near-Earth asteroids (NEAs) observed with the Sutherland, South Africa, node of the Korea Microlensing Telescope Network (KMTNet). Of the 39 NEAs, 19 were targeted, but because of KMTNet's large 2{deg}x2{deg} field of view, 20 serendipitous NEAs were also captured in the observing fields. Targeted observations were performed within 44 days (median: 16 days, min: 4 days) of each NEA's discovery date. Our broadband spectrophotometry is reliable enough to distinguish among four asteroid taxonomies and we were able to confidently categorize 31 of the 39 observed targets as either an S-, C-, X-, or D-type asteroid by means of a Machine Learning algorithm approach. Our data suggest that the ratio between "stony" S-type NEAs and "not-stony" (C+X+D)-type NEAs, with H magnitudes between 15 and 25, is roughly 1:1. Additionally, we report ~1 hr light curve data for each NEA, and of the 39 targets, we were able to resolve the complete rotation period and amplitude for six targets and report lower limits for the remaining targets.
- ID:
- ivo://CDS.VizieR/J/ApJ/838/122
- Title:
- Light curve analysis of 13 active stars
- Short Name:
- J/ApJ/838/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from light curve fits to the photometry of 13 chromospherically active stars, covering the time evolution of the rotational phase of their primary light curve minimum and the light curve amplitude.
- ID:
- ivo://CDS.VizieR/J/A+A/471/1069
- Title:
- Lunar ephemeris long-term development
- Short Name:
- J/A+A/471/1069
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this study is to develop new analytical series representing lunar coordinates to accuracy compatible with the accuracy of the modern numerical ephemeris of the Moon.
- ID:
- ivo://CDS.VizieR/J/other/JAVSO/48.201
- Title:
- Maintaining the Ephemeris of 20 CoRoT planets
- Short Name:
- J/other/JAVSO/48
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present 33 transit minimum times of 20 transiting planets discovered by the CoRoT space mission, which have been obtained from ground-based observations since the mission's end in 2012, with the objective to maintain the ephemeris of these planets and to identify potential transit time variations. Twelve of the observed planets are in the CoRoT fields near the galactic center and the remaining eight planets are in the fields near the anticenter. We detect indications for significant transit timing variations in the cases of CoRoT 3b, 11b, 13b, 27b. For two more planets (CoRoT 18b and 20b) we conclude that timing offsets in early follow-up observations led to ephemeris in discovery publications that are inconsistent with timings from follow-up observations in later epochs. In the case of CoRoT-20b, this might be due to the influence from a further non-transiting planet. We also note that a significant majority (23 of 33) of our reported minimum times have negative O-C values, albeit most of them are within the expected uncertainty of the ephemeris.
- ID:
- ivo://CDS.VizieR/J/other/JAVSO/48.202
- Title:
- Maintaining the Ephemeris of 20 CoRoT planets (Deeg+, 2020)
- Short Name:
- J/other/JAVSO/48
- Date:
- 15 Dec 2020 09:14:31
- Publisher:
- CDS
- ID:
- ivo://CDS.VizieR/J/A+A/650/A64
- Title:
- Mars moon ephemerides for 14yrs Mars Express data
- Short Name:
- J/A+A/650/A64
- Date:
- 17 Mar 2022 14:12:25
- Publisher:
- CDS
- Description:
- The Mars Express (MEX) mission has been successfully operated around Mars since 2004. Among many results, MEX has provided some of the most accurate astrometric data of the two Mars moons, Phobos and Deimos. We present new ephemerides of the Mars moons benefitting from all previously published astrometric data to the most recent MEX SRC data. Observations from 1877 until 2018 and including spacecraft measurements from Mariner 9 to MEX were included. Assuming a homogeneous interior, we fitted the forced libration amplitude of Phobos simultaneously with the Martian tidal k2/Q ratio and the initial state of the moons. Our solution of the physical libration 1.09+/-0.01 degrees deviates notably from the homogeneous solution. Considering the very low error bar, however, this may essentially suggest the necessity to consider higher order harmonics with an improved rotation model in the future. While most data could be successfully fitted, we found a disagreement between the Mars Reconnaissance Orbiter and the Mars Express astrometric data at the kilometer level, probably associated with a biased phase correction. The current solution precision is expected at the level of a few hundred meters for Phobos and several hundred meters for Deimos for the coming years. The real accuracy of our new ephemerides will have to be confirmed by comparison with independent observational means.
- ID:
- ivo://CDS.VizieR/J/A+A/320/652
- Title:
- Mass of (11) Parthenope
- Short Name:
- J/A+A/320/652
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The asteroid observations made with the automatic meridian circle at Bordeaux observatory from 1985 to 1994, and which have recently become available, are presented. The residuals of these observations obtained using the orbital elements published in the ``Ephemerides of Minor Planets for 1996'' are analysed. An anomaly for the asteroid (17) Thetis was found, indicating a current close encounter between this asteroid and (4) Vesta. Such an encounter will allow very interesting determinations of the mass of Vesta to be made in the future. Lastly, our determination of the mass of (11) Parthenope is discussed, which was based on its perturbations on the orbit of Thetis. The result obtained, (2.58+/-0.10)x10^-12^M{sun}, appears significant.
- ID:
- ivo://CDS.VizieR/J/A+A/450/855
- Title:
- Methods for CIP and CIO localisation
- Short Name:
- J/A+A/450/855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The precession-nutation transformation describes the changing directions on the celestial sphere of the Earth's pole and an adopted origin of right ascension. The coordinate system for the celestial sphere is the geocentric celestial reference system, and the two directions are the celestial intermediate pole (CIP) and the celestial intermediate origin (CIO), the latter having supplanted the equinox for this purpose following IAU resolutions in 2000. The celestial coordinate triad based on the CIP and CIO is called the celestial intermediate reference system; the prediction of topocentric directions additionally requires the Earth rotation angle (ERA), the counterpart of Greenwich sidereal time (GST) in the former equinox based system. The purpose of this paper is to review the different ways of calculating the CIP and CIO directions to precisions of a few microarcseconds over a time span of several centuries, meeting the requirements of high-accuracy applications.