Eclipses Of Jupiter Research Articles

Confirmation of Water Absorption in the Thermal Emission Spectrum of the Hot Jupiter WASP-77Ab with HST/WFC3

Secondary eclipse observations of hot Jupiters can reveal both their compositions and thermal structures. Previous observations have shown a diversity of hot Jupiter eclipse spectra, including absorption features, emission features, and featureless blackbody-like spectra. We present a secondary eclipse spectrum of the hot Jupiter WASP-77Ab observed between 1 and 5 μm with the Hubble Space Telescope (HST) and the Spitzer Space Telescope. The HST observations show signs of water absorption indicative of a noninverted thermal structure. We fit the data with both a one-dimensional free retrieval and a grid of one-dimensional self-consistent forward models to confirm this noninverted structure. The free retrieval places a 3σ lower limit on the atmospheric water abundance of and cannot constrain the CO abundance. The grid fit produces a slightly superstellar metallicity and constrains the carbon-to-oxygen ratio to less than or equal to the solar value. We also compare our data to recent high-resolution observations of WASP-77Ab taken with the IGRINS/IGRINS spectrograph. We find that the best-fit model to the IGRINS data gives a reduced chi squared of χ2 ν = 1.32 when compared to the WFC3 data. However, the metallicity derived from the IGRINS data is significantly lower than that derived from our self-consistent model fit. We find that this difference may be due to disequilibrium chemistry, and the varying results between the models applied here demonstrate the model dependence of derived metallicities when comparing to low-resolution, low-wavelength coverage data alone. Future work to combine observations from IGRINS, HST, and the James Webb Space Telescope will improve our estimate of the atmospheric composition of WASP-77Ab.

Successful Detection of a Preferred Frame Using Eclipses of Jupiter’s Moon Io

In this paper tests by Maxwell and Gift that search for a preferred frame or ether arising from movement through that frame using Jupiter’s moon Io are reviewed and discussed. Unlike the Michelson-Morley second-order experiment which unsuccessfully attempted to detect the orbital motion of the Earth relative to the ether, these tests are both first-order and therefore are unaffected by the second-order effects of length contraction and clock retardation. The test by Maxwell utilizes the delay in the eclipse of Io as the Earth orbits the Sun in an attempt to detect ether drift resulting from the galactic movement of the Sun. This test requires a 6-year duration for its full execution and was never performed because of practical difficulties. The test first presented by Gift can be conducted over a few days and employs the observed variation of the period of Io as the Earth moves toward or away from Jupiter. The result is a positive detection of ether drift arising from the orbital motion of the Earth. The detected ether drift is evidence of a preferred frame which we argue corresponds to the solar system barycentric or sun-centered inertial (SCI) frame.

Astrometric Results for Observations of Jupiter’s Galilean Satellites During Mutual Occultations and Eclipses in 2009 and 2014–2015

Photometric observations of satellites during their mutual occultations and eclipses are a valuable source of astrometric data for studying the motion of natural planetary satellites. Worldwide photometric observation campaigns are organized in order to observe as many phenomena as possible. All the photometric results obtained during such an observation campaign are stored in a single database, and after some time, they undergo astrometric processing. After conducting the campaign and publishing the results, some observers find unused data, which appear valuable. We have collected these photometric observations of mutual occultations and eclipses of Jupiter’s Galilean satellites and processed them to utilize these valuable astrometric data. To obtain astrometric data from the photometric observations, we have applied our original method. The observations come from eight observatories worldwide. As a result, this work presents 32 new relative astrometric positions of Jupiter’s Galilean satellites in 2009 and 23 new positions in 2014–2015. The astrometric accuracy of the new data in comparison with the most developed theory (O–C) is approximately 0.05′′. The internal accuracy, based on estimates for random photometry errors, is 0.02′′.

The collapse of Io's primary atmosphere in Jupiter eclipse

AbstractVolcanic outgassing due to tidal heating is the ultimate source of a tenuous SO2 atmosphere around Jupiter's moon Io. The question of whether SO2 frost on the surface plays a part, and to what degree, in maintaining Io's atmosphere with the constant volcanic outgassing is still debated. It is believed that for a sublimation‐supported atmosphere, the primary atmosphere should collapse during eclipses by Jupiter, as the SO2 vapor pressure is strongly coupled to the temperature of the ice on the surface. No direct observations of Io's atmosphere in eclipse have previously been possible, due to the simultaneous need for high spectral and time sensitivity, as well as a high signal‐to‐noise ratio. Here we present the first ever high‐resolution spectra at 19 µm of Io's SO2 atmosphere in Jupiter eclipse from the Gemini telescope. The strongest atmospheric band depth is seen to dramatically decay from 2.5 ± (0.08)% before the eclipse to 0.18 ± (0.16)% after 40 min in eclipse. Further modeling indicates that the atmosphere has collapsed shortly after eclipse ingress, implying that the atmosphere of Io has a strong sublimation‐controlled component. The atmospheric column density—from pre‐eclipse to in‐eclipse—drops by a factor of 5 ± 2.

The nature of strong temblors on earth and large coronal mass ejections on the Sun: Summer 2012

It was discovered that the dates of the earthquakes of the summer 2012, being ordered in accordance with the corresponding Carrington rotations (CR) of the Sun nos. 2123–2127, form four discrete isolated groups, with a 30-day periodicity of the earthquakes in each group. On the Sun, the moments of the earthquakes correspond to four groups of the discrete Carrington longitudes (CL) of the four-sector structure of the large-scale open solar magnetic field (LOSMF). Close to each time of occurrence of the earthquake, the strong coronal mass ejections (CME) of Halo and Particle Halo types were identified. It was unexpectedly discovered that the occurrence times of the earthquakes and the onsets of CMEs are approximately synchronous, either keeping slightly ahead or lagging somewhat behind each other. This means that the earthquakes and CMEs are governed by a common external factor. The hypothesis that this could have been caused by the influence of Jupiter is supported by the discovered phenomenon of the eclipse of Jupiter by the Sun in May–June 2012, when the Sun occurred between Jupiter and the Earth and a significant decline in the magnitudes of the quakes was detected on the Earth.

Non-detection of post-eclipse changes in Io’s Jupiter-facing atmosphere: Evidence for volcanic support?

We present observations of Io’s tenuous lower atmosphere on the Jupiter-facing hemisphere at ultraviolet wavelengths, from 2100 to 2250Å, using the Hubble Space Telescope’s Cosmic Origins Spectrometer, during the period immediately after Io emerges from Jupiter eclipse. The density of an atmosphere dominantly controlled by frost sublimation is highly dependent on the thermal properties of the surface frost and frost temperature, and the changing solar illumination conditions as Io enters and exits eclipses allow us to study the atmospheric response due to frost sublimation and its relative role compared to volcanic output. These new eclipse emergence observations were obtained to better understand the relative roles that frost sublimation and volcanoes play in supporting the overall atmosphere on Io. The observations were obtained on two separate dates, and in both cases, we observe Io post Jupiter eclipse, from approximately 2min after egress to approximately 2h post-egress. On both of these occasions, the atmospheric density was observed to be constant with time to within 15%, implying that the atmosphere did not collapse while in Jupiter eclipse. We use a thermal model to explore combinations of volcanic support and sublimation support with a variety of SO2 frost thermal inertias and bond albedos, which are consistent with these new observations. We find that a pure sublimation-supported atmosphere with a single surface component (100% frost coverage) is difficult to reconcile with the observed lack of post-eclipse atmospheric changes, unless the SO2 frost thermal inertia is very high (⩾500MKS) accompanied with moderate bond albedos (∼0.55). However, atmospheric support by high thermal inertia frost is difficult to reconcile with the dramatic cooling of much of Io’s surface in eclipse, which should lead to condensation of the atmosphere on the cold surface components. Alternatively, a Jupiter-facing atmosphere entirely dominated by volcanic emissions in which frost sublimation plays only a minor role fits the data well. The results are surprising given the previous observations of reduced FUV auroral emissions in eclipse that suggest that the atmosphere does collapse in eclipse. Future improvements to incorporate non-frost components into the thermal model will help improve our interpretations.

Roemer, Jupiter's Satellites and the Velocity of Light

The paper lists all the predictions and observations of eclipses of Jupiter's satellites 1668-1678 and compares them with modern computations of the these eclipses by J. H. Lieske. We discuss Roemer's method that led to his discovery of the retardment of light and finally we shall interpret Roemer's calculations.

Astrometric results of observations at Russian observatories of mutual occultations and eclipses of Jupiter’s Galilean satellites in 2009

In 2009, in five Russian observatories photometric observations of Jupiter’s Galilean satellites during their mutual occultations and eclipses were carried out. Based on these observations, an original method was used to ascertain astrometric results such as the difference between the coordinates of pairs of satellites. Fifty-three phenomena were successfully observed. A total of 94 light curves of satellites were measured. The error in the coordinates of satellites due to random errors in photometry, calculated on all data obtained, was 0.041″ in right ascension and 0.046″ in declination. The discrepancies between the theory and observations in these coordinates was found to be 0.060″ and 0.057″, respectively. The results were uploaded to the common database for all observations of natural satellites of planets at the Natural Satellites Data Center (NSDC), which is available online at http://www.sai.msu.ru/neb/nss/index.htm. For the first time in the practice of photometric observations of satellites in epochs of mutual occultations and eclipses a new method of observation was tested, which eliminates from astrometric results the major systematic errors caused by an inaccurate account of the background level. The tests were conducted in the Terskol Observatory and the observatory of the Crimean laboratory of the Sternberg State Astronomical Institute of the Moscow State University. The application of the new method showed that the elimination of the background level at these observatories was carried out correctly.

Io, the closest Galileo's Medicean Moon: Changes in its Sodium Cloud Caused by Jupiter Eclipse

AbstractWe report results of a study of true temporal variations in Io's sodium cloud before and after eclipse by Jupiter. The eclipse geometry is important because there is a hypothesis that the atmosphere partially condenses when the satellite enters the Jupiter's shadow, preventing sodium from being released to the cloud in the hours immediately after the reappearance. The challenge lies in disentangling true variations in sodium content from the changing strength of resonant scattering due Io's changing Doppler shift in the solar sodium absorption line. We undertook some observing runs at Telescopio Nazionale Galileo (TNG) at La Palma Canary Island with the high resolution spectrograph SARG in order to observe Io entering into Jupiter's shadow and coming out from it. The particular configuration chosen for the observations allowed us to observe Io far enough from Jupiter and to disentangle line-of-sight effects looking perpendicularly at the sodium cloud. We will present results which took advantage of a very careful reduction strategy. We remove the dependence from γ-factor, which is the fraction of solar light available for resonant scattering, in order to remove the dependence on the radial velocity of Io with respect to the Sun.This work has been supported by NSF's Planetary Astronomy Program, INAF/TNG and the Department of Astronomy and Cisas of University of Padova, through a contract by the Italian Space Agency ASI.

Io Volcanism Seen by New Horizons: A Major Eruption of the Tvashtar Volcano

Jupiter's moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io's volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62 degrees N, 122 degrees W), and its motion was observed. The plume's morphology and dynamics support nonballistic models of large Io plumes and also suggest that most visible plume particles condensed within the plume rather than being ejected from the source. In images taken in Jupiter eclipse, nonthermal visible-wavelength emission was seen from individual volcanoes near Io's sub-Jupiter and anti-Jupiter points. Near-infrared emission from the brightest volcanoes indicates minimum magma temperatures in the 1150- to 1335-kelvin range, consistent with basaltic composition.

Victor Ambros

Victor Ambros

Developing an Astronomical Observatory in Paraguay

Background: Paraguay has some heritage from the astronomy of the Guarani Indians. Buenaventura Suarez S.J. was a pioneer astronomer in the country in the XVIII century. He built various astronomical instruments and imported others from England. He observed eclipses of Jupiter’s satellites and of the Sun and Moon. He published his data in a book and through letters. The Japanese O.D. A. has collaborated in obtaining equipment and advised their government to assist Paraguay in building an astronomical observatory, constructing a moving-roof observatory and training astronomers as observatory operators. Future: An astronomical center is on the horizon and some possible fields of research are being considered. Goal: To improve education at all possible levels by not only observing sky wonders, but also showing how instruments work and teaching about data and image processing, saving data and building a data base. Students must learn how a modern scientist works.

Discovery of hotspots on Io using disk-resolved infrared imaging

ACTIVE, tidally driven volcanism on Jupiter's satellite Io1,2 was discovered in Voyager images in 1979. Voyager also detected the thermal emission from the volcanoes3,4, and this emission has since been monitored from Earth using a variety of techniques employing single-element infrared detectors5–10. Because of Io's small angular size (no more than 1.2 arcsec), however, it has normally been possible to resolve and locate only the brightest individual hotspot, Loki, although additional hotspots can be located at five-year intervals during occultations of Io by the other galilean satellites11,12. Here we present first results using two new techniques for ground-based observation of Io's hotspots. First, use of an infrared array camera allowed us to exploit the Mauna Kea Observatory's excellent atmospheric stability to obtain direct infrared images of Io with resolution better than 0.5 arcsec. This allowed us to see more than one hotspot on Io in Jupiter eclipse (in Jupiter's shadow). Second, we used the camera to make the first observations of the Jupiter occultation (disappearance behind Jupiter) of the hotspots. These new techniques have revealed and located at least three hotspots, and will now permit routine ground-based monitoring of the locations, temperatures and sizes of multiple hotspots on Io.

On the velocity of light three centuries ago

view Abstract Citations (7) References (2) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the velocity of light three centuries ago Goldstein, S. J., Jr. ; Ogburn, T. J., III ; Trasco, J. D. Abstract Observations of the times of eclipses of Jupiter's satellite lo by Picard and Roemer were reduced by the principle of least squares with modern orbits for Earth and Jupiter. The best-fitting value for the light travel time across one astronomical unit does not differ from the currently accepted value by one part in 200. The rms deviation between the observations and our model is 118 sec. Publication: The Astronomical Journal Pub Date: February 1973 DOI: 10.1086/111387 Bibcode: 1973AJ.....78..122G full text sources ADS |

Strong Beaming of Jupiter's Non-Io-related Radio Emission

THE apparent decrease, after opposition, in the rate of receipt of decametric radiation from the planet Jupiter has been attributed to the eclipse of Jupiter by the Earth's magnetosphere1. Dulk (private communication) noticed this effect when drawing histograms separately for the period before and after opposition for the apparitions in 1964 and 1965 and suggested that it might be due to the influence of the maximum usable frequency of the Earth's ionosphere on the reception of Jupiter's decametric radiation. But Gruber2 showed that the Earth's ionosphere cannot significantly influence the probability of receiving Jupiter's decametric radiation over an apparition. He attempted to determine the possible influence of Jupiter's magnetospheric tail and explained the observed effects by assuming two different sources.

Observations of eclipses of Jupiter's satellites

Observations of eclipses of Jupiter's satellites

Observations of eclipses of Jupiter's satellites

Observations of eclipses of Jupiter's satellites

Eclipses of Jupiter's satellites observed in 1949

Eclipses of Jupiter's satellites observed in 1949

Eclipses of Jupiter's satellites observed in 1947-48

Eclipses of Jupiter's satellites observed in 1947-48

Astronomical Topics

Astronomical Notes for February. Jupiter, Mars and Neptune are all near opposition, and are observable for most of the night. The northern hemisphere of Mars is turned towards us; this is less well known than the southern hemisphere, being turned to us at aphelion oppositions. The diameter of Mars increases during February from 12″ to nearly 14″. There is an eclipse of Jupiter IV on February 12; the disappearance is at 8.11 p.M. when Jupiter will be too low; but the re-appearance at 11.54 P.M. is observable. Two stars in the Pleiades are occulted by the moon on February 3, disappearing at 8.43 and 9.34 P.M.