Carnival of Space 33

by | Dec 15, 2007 | Culture and Society | 7 comments

Universe Today offers the latest Carnival of Space, which will have exoplanet watchers checking Steinn Sigurðsson’s Dynamics of Cats site for updates on CoRoT. Almost a year into its mission, the observatory has completed its first 150-day continuous examination of the same area of sky, and the results are, so rumor has it, quite interesting. I see that CNES (Centre National d’Études Spatiales) is now saying that ‘CoRoT will instigate a breakthrough in both of the fields of science that it applies to,’ making the upcoming publication of CoRoT papers eagerly to be awaited. And you have to love this statement: “”…CoRoT is discovering exo-planets at a rate only set by the available resources to follow up the detections.”

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7 Comments

  1. AlfaCentavra on December 16, 2007 at 18:44

    We will just have to wait about a week, the upcoming December 20 is the day to stay alert.
    According to the mission’s happy Project Scientist, there will be in that day’s morning, a press conference at the Paris Observatory (about CoRoT).
    Fridlund (COROT’s Project Scientist) also indicates that there will be a simultaneous press release at a time yet to be decided but it will be around noon.

  2. ljk on December 20, 2007 at 11:42

    The space-borne telescope, COROT (Convection, Rotation and planetary Transits), has just completed its first year in orbit. The observatory has brought in surprises after over 300 days of scientific observations.

    Read more at:

    http://www.esa.int/SPECIALS/COROT/SEMF0C2MDAF_0.html

  3. ljk on January 9, 2008 at 0:53

    Reconstruction of the transit signal in the presence of stellar variability

    Authors: Aude Alapini (1), Suzanne Aigrain (1) ((1) University of Exeter)

    (Submitted on 8 Jan 2008)

    Abstract: Intrinsic stellar variability can hinder the detection of shallow transits, particularly in space-based data. Therefore, this variability has to be filtered out before running the transit search. Unfortunately, filtering out the low frequency signal of the stellar variability also modifies the transit shape. This results in errors in the measured transit depth and duration used to derive the planet radius, and orbital inclination.

    We present an evaluation of the magnitude of this effect based on 20 simulated light curves from the CoRoT blind exercise 2 (BT2). We then present an iterative filter which uses the strictly periodic nature of the transits to separate them from other forms of variability, so as to recover the original transit shape before deriving the planet parameters. On average with this filter, we improve the estimation of the transit depth and duration by 15% and 10% respectively.

    Comments: 4 pages, 2 figures. Accepted for publication in the Proceedings of IAU Symposium 249: Exoplanet: Detection, Formation and Dynamics

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0801.1237v1 [astro-ph]

    Submission history

    From: Aude Alapini [view email]

    [v1] Tue, 8 Jan 2008 14:11:58 GMT (362kb)

    http://arxiv.org/abs/0801.1237

  4. ljk on April 2, 2008 at 10:53

    Transiting exoplanets from the CoRoT space mission I – CoRoT-Exo-1b: a low-density short-period planet around a G0V star

    Authors: P. Barge, A. Baglin, M. Auvergne, H. Rauer, A. Leger, J. Schneider, F. Pont, S. Aigrain, J.-M. Almenara, R. Alonso, M. Barbieri, P. Borde, F. Bouchy, H.-J. Deeg, R. De la Reza, M. Deleuil, R. Dvorak, A. Erikson, M. Fridlund, M. Gillon, P. Gondoin, T. Guillot, A. Hatzes, G. Hebrard, L. Jorda, P. Kabath, H. Lammer, A. Llebaria, B. Loeillet, P. Magain, T. Mazeh, C. Moutou, M. Ollivier, M. Patzold, D. Queloz, D. Rouan, A. Shporer, G. Wuchterl

    (Submitted on 21 Mar 2008)

    Abstract: Context. The pioneer space mission for photometric planet searches, CoRoT, steadily monitors about 12,000 stars in each of its fields of view; it is able to detect transit candidates early in the processing of the data and before the end of a run.

    Aims. We report the detection of the first planet discovered by CoRoT and characterizing it with the help of follow-up observations.

    Methods. Raw data were filtered from outliers and residuals at the orbital period of the satellite. The orbital parameters and the radius of the planet were estimated by best fitting the phase folded light curve with 34 successive transits. Doppler measurements with the SOPHIE spectrograph permitted us to secure the detection and to estimate the planet mass.

    Results. The accuracy of the data is very high with a dispersion in the 2.17 min binned phase-folded light curve that does not exceed 3.10-4 in flux unit. The planet orbits a mildly metal-poor G0V star of magnitude V=13.6 in 1.5 days. The estimated mass and radius of the star are 0.95+-0.15Msun and 1.11+-0.05Rsun. We find the planet has a radius of 1.49+-0.08Rjup, a mass of 1.03+-0.12Mjup, and a particularly low mean density of 0.38 +-0.05g cm-3.

    Comments: A&A letters (in press) – 4 pages – 3 figures

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0803.3202v1 [astro-ph]

    Submission history

    From: Barge Pierre [view email]

    [v1] Fri, 21 Mar 2008 18:32:53 GMT (195kb)

    http://arxiv.org/abs/0803.3202

  5. ljk on April 2, 2008 at 10:54

    Transiting exoplanets from the CoRoT space mission II. CoRoT-Exo-2b: A transiting planet around an active G star

    Authors: R. Alonso, M. Auvergne, A. Baglin, M. Ollivier, C. Moutou, D. Rouan, H.J. Deeg, S. Aigrain, J.M. Almenara, M. Barbieri, P. Barge, W. Benz, P. Bordé, F. Bouchy, R. De la Reza, M. Deleuil, R. Dvorak, A. Erikson, M. Fridlund, M. Gillon, P. Gondoin, T. Guillot, A. Hatzes, G. Hébrard, P. Kabath, L. Jorda, H. Lammer, A. Léger, A. Llebaria, B. Loeillet, P. Magain, M. Mayor, T. Mazeh, M. Pätzold, F. Pepe, F. Pont, D. Queloz, H. Rauer, A. Shporer, J. Schneider, B. Stecklum, S. Udry, G. Wuchterl

    (Submitted on 21 Mar 2008)

    Abstract: Context. The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12000 stars in the galactic plane. An analysis of the raw data identifies the most promising candidates and triggers the ground-based follow-up.

    Aims. We report on the discovery of the transiting planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its main parameters.

    Methods. We filter the CoRoT raw light curve of cosmic impacts, orbital residuals, and low frequency signals from the star. The folded light curve of 78 transits is fitted to a model to obtain the main parameters. Radial velocity data obtained with the SOPHIE, CORALIE and HARPS spectro-graphs are combined to characterize the system. The 2.5 min binned phase-folded light curve is affected by the effect of sucessive occultations of stellar active regions by the planet, and the dispersion in the out of transit part reaches a level of 1.09×10-4 in flux units.

    Results. We derive a radius for the planet of 1.465+-0.029 R_Jup and a mass of 3.31+-0.16 M_Jup, corresponding to a density of 1.31+-0.04 g/cm^3. The large radius of CoRoT-Exo-2b cannot be explained by current models of evolution of irradiated planets.

    Comments: A&A Letters (in press), 7 pages, 3 figures

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0803.3207v1 [astro-ph]

    Submission history

    From: Roi Alonso [view email]

    [v1] Fri, 21 Mar 2008 18:22:18 GMT (99kb)

    http://arxiv.org/abs/0803.3207

  6. ljk on April 2, 2008 at 10:56

    Transiting exoplanets from the CoRoT space mission III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS

    Authors: F. Bouchy, D. Queloz, M. Deleuil, B. Loeillet, A.P. Hatzes, S. Aigrain, R. Alonso, M. Auvergne, A. Baglin, P. Barge, W. Benz, P. Bordé, H.J. Deeg, R. De la Reza, R. Dvorak, A. Erikson, M. Fridlund, P. Gondoin, T. Guillot, G. Hébrard, L. Jorda, H. Lammer, A. Léger, A. Llebaria, P. Magain, M. Mayor, C. Moutou, M. Ollivier, M. Pätzold, F. Pepe, F. Pont, H. Rauer, D. Rouan, J. Schneider, A.H.M.J. Triaud, S. Udry, G. Wuchterl

    (Submitted on 21 Mar 2008)

    Abstract: We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda=7.2+-4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented.

    Comments: A&A Letters (in press), 5 pages, 2 figures

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0803.3209v1 [astro-ph]

    Submission history

    From: Roi Alonso [view email]

    [v1] Fri, 21 Mar 2008 18:23:59 GMT (28kb)

    http://arxiv.org/abs/0803.3209

  7. ljk on May 21, 2008 at 13:50

    Two new exoplanets and an unknown celestial object are the
    latest findings of the COROT mission. These discoveries mean
    that the mission has now found a total of four new exoplanets.

    More at:

    http://www.esa.int/esaSC/SEM9E91YUFF_index_0.html

    Not only is one of the objects a mystery in terms of being
    unable to yet determine if it is a brown dwarf, a small star,
    or a really unusual planet, but one of the planets may be
    only 1.7 times more massive than Earth!

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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