Number of results to display per page
Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/156/112
- Title:
- Near-infrared Mira period-luminosity relations in M33
- Short Name:
- J/AJ/156/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze sparsely sampled near-infrared (JHK_s_) light curves of a sample of 1781 Mira variable candidates in M33, originally discovered using I-band time-series observations. We extend our single-band semi-parametric Gaussian process modeling of Mira light curves to a multiband version and obtain improved period determinations. We use our previous results on near-infrared properties of candidate Miras in the LMC to classify the majority of the M33 sample into oxygen- or carbon-rich subsets. We derive period-luminosity relations for O-rich Miras and determine a distance modulus for M33 of 24.80+/-0.06 mag.
- ID:
- ivo://CDS.VizieR/J/MNRAS/376/573
- Title:
- New times of minima of VZ CVn
- Short Name:
- J/MNRAS/376/573
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric two-colour observations of the double-lined close binary star VZ CVn. Combining two data sets obtained in 1971-72 and in 2006, the physical parameters of both components were derived. After removing the light variations due to the eclipses and proximity effects, a periodic variation in the more massive component with a dominant period of 1.06876d could be detected in the first photometric data set. In accordance with its position on the Hertzsprung-Russell diagram and both its pulsation period and pulsation constant of 0.62d, the primary component of VZ CVn should be an excellent {gamma} Doradus candidate. The less massive secondary component seems to have smaller radius with respect to its mass. Both components appear to have lower luminosities with respect to their masses; hence, their radiative properties seem to be different. The evolutionary status of the components is also discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A96
- Title:
- Observations of 50 TNOs and Centaurs
- Short Name:
- J/A+A/584/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prediction of stellar occultations by trans-Neptunian objects (TNOs) and Centaurs is a difficult challenge that requires accuracy both in the occulted star position and in the object ephemeris. Until now, the most used method of prediction, involving dozens of TNOs/Centaurs, has been to consider a constant offset for the right ascension and for the declination with respect to a reference ephemeris, usually the latest public version. This offset is determined as the difference between the most recent observations of the TNO/Centaur and the reference ephemeris. This method can be successfully applied when the offset remains constant with time, i.e. when the orbit is stable enough. In this case, the prediction even holds for occultations that occur several days after the last observations. This paper presents an alternative method of prediction, based on a new accurate orbit determination procedure, which uses all the available positions of the TNO from the Minor Planet Center database, as well as sets of new astrometric positions from unpublished observations. Orbits were determined through a numerical integration procedure called NIMA, in which we developed a specific weighting scheme that considers the individual precision of the observation, the number of observations performed during one night by the same observatory, and the presence of systematic errors in the positions.
- ID:
- ivo://CDS.VizieR/J/AJ/109/1363
- Title:
- Occultations of stars by asteroids 1995-96
- Short Name:
- J/AJ/109/1363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Predictions, based on a computerized comparison of asteroid ephemerides with the catalog positions of 567,500 stars, are given for 155 occultations of stars by asteroids in 1995 and 1996. On average, the predictions are expected to be more accurate than in earlier searches because of the use of more modern star catalogs. A number of very favorable occultations, visible in North Armerica and elsewhere, are discussed.