A5073725092- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Mechanics and Biomechanics Studies
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- History and Developments in Astronomy
- Relativity and Gravitational Theory
- High-pressure geophysics and materials
- Adaptive optics and wavefront sensing
- Space Exploration and Technology
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Scientific Research and Discoveries
- SAS software applications and methods
- Experimental and Theoretical Physics Studies
- Particle Accelerators and Free-Electron Lasers
- History and Theory of Mathematics
- Scientific Measurement and Uncertainty Evaluation
- Inertial Sensor and Navigation
San Diego State University
2015-2024
OMV Petrom (Romania)
2023
Vienna Consulting Engineers (Austria)
2016-2020
Center for Astrophysics Harvard & Smithsonian
2010
Northwestern University
2010
McMaster University
2010
National Astronomical Observatories
2010
Chinese Academy of Sciences
2010
Utrecht University
2000-2006
IAC (United States)
2004
We report the detection of a planet whose orbit surrounds pair low-mass stars. Data from Kepler spacecraft reveal transits across both stars, in addition to mutual eclipses giving precise constraints on absolute dimensions all three bodies. The is comparable Saturn mass and size, nearly circular 229-day around its two parent eclipsing stars are 20% 69% as massive sun, have an eccentric 41-day orbit. motions bodies confined within 0.5 degree single plane, suggesting that formed circumbinary disk.
The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg2 field of view features over 156,000 that are observed continuously detect and characterize planet transits. Yet, this high-precision instrument holds great promise for types objects as well. Here we present a comprehensive catalog eclipsing binary by the first 44 days operation, data being publicly available through MAST 2010 June 15. contains 1879 unique...
The Kepler Mission provides nearly continuous monitoring of ~156 000 objects with unprecedented photometric precision. Coincident the first data release, we presented a catalog 1879 eclipsing binary systems identified within 115 square degree FOV. Here, provide an updated augmented second release which increases baseline 4-fold to 125 days. 386 new have been added, ephemerides and principle parameters recomputed. We removed 42 previously cataloged that are now clearly recognized as...
The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection two Saturn-size that transit same Sun-like star, based on 7 months observations. Their 19.2- and 38.9-day periods are presently increasing decreasing at respective average rates 4 39 minutes per orbit; in addition, times inner body display an alternating variation smaller amplitude. These signatures characteristic gravitational interaction near a 2:1 orbital...
ABSTRACT The primary Kepler Mission provided nearly continuous monitoring of ∼200,000 objects with unprecedented photometric precision. We present the final catalog eclipsing binary systems within 105 deg 2 field view. This release incorporates full extent data from mission (Q0-Q17 Data Release). As a result, new have been added, additional false positives removed, ephemerides and principal parameters recomputed, classifications revised to rely on analytical models, eclipse timing variations...
We report the detection of Kepler-47, a system consisting two planets orbiting around an eclipsing pair stars. The inner and outer have radii 3.0 4.6 times that Earth, respectively. binary star consists Sun-like companion roughly one-third its size, each other every 7.45 days. With orbital period 49.5 days, eighteen transits planet been observed, allowing detailed characterization orbit those planet's is 303.2 although not Earth-like, it resides within classical "habitable zone", where...
A typical galaxy is thought to contain tens of millions stellar-mass black holes, the collapsed remnants once massive stars, and a single nuclear supermassive hole. Both classes holes accrete gas from their environments. The accreting forms flattened orbiting structure known as an accretion disk. During past several years, it has become possible obtain measurements spins two by modeling X-ray emission disks. Two methods are employed, both which depend upon identifying inner radius disk with...
Cygnus X-1 is a binary star system that comprised of black hole and massive giant companion in tight orbit. Building on our accurate distance measurement reported the preceding paper, we first determine radius star, thereby constraining scale system. To obtain full dynamical model binary, use an extensive collection optical photometric spectroscopic data taken from literature. By using all available observational constraints, show orbit slightly eccentric (both radial velocity independently...
We present the detection of five planets -- Kepler-62b, c, d, e, and f size 1.31, 0.54, 1.95, 1.61 1.41 Earth radii, orbiting a K2V star at periods 5.7, 12.4, 18.2, 122.4 267.3 days, respectively. The outermost (Kepler-62e & -62f) are super-Earth-size (1.25 < planet radius/earth radius 2.0) in habitable zone (HZ) their host star, receiving 1.2 +- 0.2 0.41 0.05 times solar flux Earth's orbit. Theoretical models Kepler-62e -62f for stellar age ~7 Gyr suggest that both could be solid: either...
The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here we report on detection of an eclipsing stellar hierarchical triple, identified photometry. KOI-126 (A,(B, C)), is composed a low-mass binary (masses M_B = 0.2413+/-0.0030 M_Sun, M_C 0.2127+/-0.0026 M_Sun; radii R_B 0.2543+/-0.0014 R_Sun, R_C 0.2318+/-0.0013 R_Sun; orbital period P_1 1.76713+/-0.00019 days) eccentric orbit about third star (mass M_A 1.347+/-0.032...
We discuss the discovery and characterization of circumbinary planet Kepler-38b. The stellar binary is single-lined, with a period 18.8 days, consists moderately evolved main-sequence star (M_A = 0.949 +/- 0.059 solar masses R_A 1.757 0.034 radii) paired low-mass (M_B 0.249 0.010 R_B 0.2724 0.0053 in mildly eccentric (e=0.103) orbit. A total eight transits due to crossing primary were identified Kepler light curve (using Quarters 1 through 11), from which planetary 105.595 0.053 days can be...
A heavy black hole in an x-ray binary If a interacts with companion star, the system emits x-rays and can form radio jet. The masses of holes these binaries are all lower than those detected using gravitational waves, challenging models formation from massive stars. Miller-Jones et al. used astrometry to refine distance Cygnus X-1, well-studied binary. They found larger previous estimates, raising mass 21 solar masses. results challenge wind loss rates implemented stellar evolution models....
In this paper we present a catalog of 4584 eclipsing binaries observed during the first two years (26 sectors) TESS survey. We discuss selection criteria for binary candidates, detection hither-to unknown systems, determination ephemerides, validation and triage process, derivation heuristic estimates ephemerides. Instead keeping to widely used discrete classes, propose star morphology classification based on dimensionality reduction algorithm. Finally, statistical properties sample,...
We report photometric and spectroscopic observations of the black hole binary GRO J1655-40 in complete quiescence. In contrast to 1995 photometry, light curves from 1996 are almost completely dominated by ellipsoidal modulations secondary star. Model fits curves, which take into account temperature profile accretion disk eclipse effects, yield an inclination i = 6950 ± 008 a mass ratio Q M1/M2 2.99 0.08. The precision our determinations allow us determine accuracy ≈ 4% (M1 7.02 0.22 M☉)....
We have discovered at x-ray and radio wavelengths large-scale moving jets from the microquasar XTE J1550-654. Plasma ejected near black hole traveled relativistic velocities for least four years. present direct evidence gradual deceleration in a jet. The broadband spectrum of is consistent with synchrotron emission high energy (up to 10 TeV) particles accelerated shock waves formed within ejecta or by interaction interstellar medium. J1550-654 offers unique opportunity study dynamical...
The compact primary in the X-ray binary Cygnus X-1 was first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, orbital inclination angle of binary. Building on these results, which are based our favored (asynchronous) model, we measured radius inner edge hole's accretion disk by fitting thermal continuum spectrum a fully relativistic model thin disk. Assuming that spin axis is aligned with angular momentum vector,...
We report a direct and accurate measurement of the distance to X-ray binary Cygnus X-1, which contains first black hole be discovered. The 1.86 (-0.11,+0.12) kpc was obtained from trigonometric parallax using Very Long Baseline Array. position measurements are also sensitive 5.6 d orbit we determine clockwise on sky. measured proper motion X-1 which, when coupled Doppler shift, gives three-dimensional space system. When corrected for differential Galactic rotation, non-circular (peculiar) is...
We present BVIJK photometry of the black hole candidate GRO J1655-40 in full quiescence. report a refined orbital period 2.62191 ± 0.00020 days. The light curves are dominated by ellipsoidal variations from secondary star. model with an upgraded code that includes more accurate treatment limb darkening. Previous models containing large cool disk ruled out, and, indeed, our data can be fitted pure curve without any contribution. In general agreement previous results, we derive confidence...
We present an improved method for determining the mass of neutron stars in eclipsing X-ray pulsar binaries and apply to six systems, namely Vela X-1, 4U 1538-52, SMC LMC X-4, Cen X-3, Her X-1. In previous studies determine star mass, eclipse duration has been approximated analytically by assuming companion is spherical with effective Roche lobe radius. use a numerical code based on geometry various optimizers analyze published data these which we supplement new spectroscopic photometric...
We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in Kepler field. The was discovered by volunteers searching first six Quarters publicly available data as part Planet Hunters citizen science project. Transits across larger brighter stars are detectable visual inspection every ~137 days, with seven transits identified 1-11. physical orbital parameters both host were obtained via photometric-dynamical model,...
We measure the spin of XTE J1550−564 using two leading methods: (i) modelling thermal continuum spectrum accretion disc; and (ii) broad red wing reflection fluorescence Fe Kα line. find that these independent measurements are in agreement. For continuum-fitting analysis, we use a data sample consisting several dozen Rossi X-ray Timing Explorer spectra, for pair ASCA spectra from single epoch. Our estimate black hole primary method is −0.11 < a* 0.71 (90 per cent confidence), with most likely...
We report the discovery of a transiting, Rp = 4.347 ± 0.099R⊕, circumbinary planet (CBP) orbiting Kepler K+M eclipsing binary (EB) system KIC 12351927 (Kepler-413) every ∼66 days on an eccentric orbit with ap 0.355 0.002 AU, ep 0.118 0.002. The two stars, MA 0.820 0.015 M☉, RA 0.776 0.009 R☉ and MB 0.542 0.008 RB 0.484 0.024 R☉, respectively, revolve around each other 10.11615 0.00001 nearly circular (eEB 0.037 0.002) orbit. orbital plane EB is slightly inclined to line sight (iEB 8733 006),...