ORCID Profile
0000-0002-5854-4217
Current Organisation
Universität Hamburg
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Publisher: EDP Sciences
Date: 08-10-2009
Publisher: American Astronomical Society
Date: 28-12-2017
Publisher: American Astronomical Society
Date: 18-08-2023
Abstract: We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ 2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q , and separation, s , cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ∼ 5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1038/NATURE04441
Abstract: In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.
Publisher: Wiley
Date: 2009
Publisher: Oxford University Press (OUP)
Date: 10-2013
Publisher: EDP Sciences
Date: 25-10-2012
Publisher: American Astronomical Society
Date: 17-08-2010
Publisher: American Astronomical Society
Date: 12-10-2011
Publisher: American Astronomical Society
Date: 02-03-2016
Publisher: American Astronomical Society
Date: 26-03-2010
Publisher: American Astronomical Society
Date: 22-03-2016
Publisher: American Astronomical Society
Date: 23-04-2013
Publisher: American Astronomical Society
Date: 19-10-2009
Publisher: American Astronomical Society
Date: 02-02-2010
Publisher: American Astronomical Society
Date: 28-06-2016
Publisher: American Astronomical Society
Date: 07-10-2010
Publisher: American Astronomical Society
Date: 14-11-2012
Publisher: EDP Sciences
Date: 27-03-2013
Publisher: American Astronomical Society
Date: 13-08-2012
Publisher: American Astronomical Society
Date: 04-06-2009
Publisher: American Astronomical Society
Date: 27-11-2013
Publisher: American Astronomical Society
Date: 02-2012
Publisher: American Astronomical Society
Date: 28-01-2011
Publisher: American Astronomical Society
Date: 30-05-2012
Publisher: American Astronomical Society
Date: 17-01-2013
Publisher: American Astronomical Society
Date: 06-05-2013
Publisher: Oxford University Press (OUP)
Date: 11-05-2009
Publisher: American Astronomical Society
Date: 23-05-2016
Publisher: American Astronomical Society
Date: 07-2022
Abstract: We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration ( t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of 6 yr, reveals a clear relativistic astrometric deflection of the background star’s apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of Earth’s motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 ± 1.3 M ⊙ and a distance of 1.58 ± 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic disk stars at similar distances by an amount corresponding to a transverse space velocity of ∼45 km s −1 , suggesting that the BH received a “natal kick” from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial velocity measurements of Galactic X-ray binaries and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique.
Publisher: EDP Sciences
Date: 04-03-2008
Publisher: Oxford University Press (OUP)
Date: 10-02-2011
Publisher: American Astronomical Society
Date: 02-05-2012
Publisher: American Astronomical Society
Date: 20-06-2011
Publisher: American Astronomical Society
Date: 28-04-2015
Publisher: American Astronomical Society
Date: 07-04-2009
Publisher: American Astronomical Society
Date: 06-07-2012
Publisher: American Astronomical Society
Date: 07-11-2016
Publisher: EDP Sciences
Date: 07-2010
Publisher: American Astronomical Society
Date: 31-07-2012
Publisher: American Astronomical Society
Date: 27-04-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-02-2008
Abstract: Searches for extrasolar planets have uncovered an astonishing ersity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of ∼0.71 and ∼0.27 times the mass of Jupiter and orbital separations of ∼2.3 and ∼4.6 astronomical units orbiting a primary star of mass ∼0.50 solar mass at a distance of ∼1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.
Publisher: EDP Sciences
Date: 12-04-2011
Publisher: American Astronomical Society
Date: 14-10-2010
Publisher: Oxford University Press (OUP)
Date: 02-07-2012
Publisher: EDP Sciences
Date: 25-06-2013
Publisher: American Astronomical Society
Date: 08-01-2013
Publisher: IOP Publishing
Date: 25-10-2016
Location: Germany
No related grants have been discovered for Martin Burgdorf.