Comments on: Rocky World Discovered Through Microlensing http://www.centauri-dreams.org/?p=520&utm_source=rss&utm_medium=rss&utm_campaign=rocky-world-discovered-through-microlensing The News Forum of the Tau Zero Foundation Wed, 08 Sep 2010 10:10:46 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: ljk http://www.centauri-dreams.org/?p=520&cpage=1#comment-56063 ljk Wed, 14 May 2008 18:17:00 +0000 http://www.centauri-dreams.org/?p=520#comment-56063 High magnification events by MOA in 2007 Authors: Philip Yock (Submitted on 13 May 2008) Abstract: Gravitational microlensing events of high magnification provide exceptional sensitivity to the presence of low-mass planets orbiting the lens star, including planets with masses as low as that of Earth. The essential requirement for the detection of such planets in these events is that the FWHM of the light curve be monitored continuously, or as nearly continuously as possible. The dependence of planet detectability on the magnification caused by microlensing, on the planet mass and planet location, and on the size of the source star, may be understood in terms of simple geometrical properties of microlensing that have been known since 1964. Planetary signals of low-mass planets are found to be approximately independent of the magnification caused by microlensing. This implies that planets can be detected in events over a wide range of magnifications, from moderately high values ~ 100 to very high values ~ 1000. The former values are likely to yield more clear-cut separations of the stellar and planetary features on the light curve, but they require larger telescopes to obtain precision photometry. During 2007, twenty-four events with magnification exceeding 50 were detected by the MOA collaboration, of which about half were also detected by the OGLE collaboration. A quarter of the events received essentially continuous coverage of their FWHMs by follow-up collaborations, another quarter received partial coverage, and the remaining half received little coverage. Final analysis of these events is still underway, but casual inspection of the light curves reveals some possible planetary detections amongst them. During 2008 it is hoped that fuller coverage of events of high magnification will be obtained with the addition of further telescopes to existing follow-up networks. Comments: 13 pages, 17 figures, Manchester Microlensing Conference, January 2008. To be published in the proceedings Subjects: Astrophysics (astro-ph) Cite as: arXiv:0805.1775v1 [astro-ph] Submission history From: Philip Yock [view email] [v1] Tue, 13 May 2008 04:07:02 GMT (304kb) http://arxiv.org/abs/0805.1775 High magnification events by MOA in 2007

Authors: Philip Yock

(Submitted on 13 May 2008)

Abstract: Gravitational microlensing events of high magnification provide exceptional sensitivity to the presence of low-mass planets orbiting the lens star, including planets with masses as low as that of Earth. The essential requirement for the detection of such planets in these events is that the FWHM of the light curve be monitored continuously, or as nearly continuously as possible.

The dependence of planet detectability on the magnification caused by microlensing, on the planet mass and planet location, and on the size of the source star, may be understood in terms of simple geometrical properties of microlensing that have been known since 1964.

Planetary signals of low-mass planets are found to be approximately independent of the magnification caused by microlensing. This implies that planets can be detected in events over a wide range of magnifications, from moderately high values ~ 100 to very high values ~ 1000. The former values are likely to yield more clear-cut separations of the stellar and planetary features on the light curve, but they require larger telescopes to obtain precision photometry.

During 2007, twenty-four events with magnification exceeding 50 were detected by the MOA collaboration, of which about half were also detected by the OGLE collaboration. A quarter of the events received essentially continuous coverage of their FWHMs by follow-up collaborations, another quarter received partial coverage, and the remaining half received little coverage.

Final analysis of these events is still underway, but casual inspection of the light curves reveals some possible planetary detections amongst them. During 2008 it is hoped that fuller coverage of events of high magnification will be obtained with the addition of further telescopes to existing follow-up networks.

Comments: 13 pages, 17 figures, Manchester Microlensing Conference, January 2008. To be published in the proceedings

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0805.1775v1 [astro-ph]

Submission history

From: Philip Yock [view email]

[v1] Tue, 13 May 2008 04:07:02 GMT (304kb)

http://arxiv.org/abs/0805.1775

]]> By: Centauri Dreams » Blog Archive » Death of an Astrophysicist http://www.centauri-dreams.org/?p=520&cpage=1#comment-37658 Centauri Dreams » Blog Archive » Death of an Astrophysicist Tue, 01 May 2007 20:45:36 +0000 http://www.centauri-dreams.org/?p=520#comment-37658 [...] that’s just what OGLE did last year in discovering one of the smallest planets yet found, a rocky world orbiting a star some 20,000 light years away. Gravitational lensing [...] [...] that’s just what OGLE did last year in discovering one of the smallest planets yet found, a rocky world orbiting a star some 20,000 light years away. Gravitational lensing [...]

]]> By: Anthonares » Blog Archive » Published Research Synopsis: 5.5 Earth Mass Exoplanet Found http://www.centauri-dreams.org/?p=520&cpage=1#comment-87 Anthonares » Blog Archive » Published Research Synopsis: 5.5 Earth Mass Exoplanet Found Wed, 08 Feb 2006 01:50:41 +0000 http://www.centauri-dreams.org/?p=520#comment-87 [...] Published Research Synopsis: 5.5 Earth Mass Exoplanet Found Astronomy» ESA» Exoplanet» Gravitational Lensing» Microlensing» OGLE 2005 BLG 390Lb» Research Synopsis» Science» In a press conference this morning, astronomers announced the discovery of a planet with a likely mass of 5.5 times that of the Earth orbiting a red dwarf star some 21,500 light years away. This is not the lowest mass exoplanet discovered thus far, but it is the first one that is both near Earth mass and near Earth orbital distance. I’m sure you’ve all heard the news, but now read on and hear the science (I’ll note that the Bad Astronomer did a science explanation too, but mine has pictures and graphs in it, so it must be better! Okay, also Centauri Dreams has done a summary as well, but again, mine has more pictures and graphs, plus an original analysis in the Context section below.). Also, I made a cool graph of all of the exoplanets we’ve found so far, that’s below too. So, here’s a second bonus published research synopsis in as many weeks: [...] [...] Published Research Synopsis: 5.5 Earth Mass Exoplanet Found Astronomy» ESA» Exoplanet» Gravitational Lensing» Microlensing» OGLE 2005 BLG 390Lb» Research Synopsis» Science» In a press conference this morning, astronomers announced the discovery of a planet with a likely mass of 5.5 times that of the Earth orbiting a red dwarf star some 21,500 light years away. This is not the lowest mass exoplanet discovered thus far, but it is the first one that is both near Earth mass and near Earth orbital distance. I’m sure you’ve all heard the news, but now read on and hear the science (I’ll note that the Bad Astronomer did a science explanation too, but mine has pictures and graphs in it, so it must be better! Okay, also Centauri Dreams has done a summary as well, but again, mine has more pictures and graphs, plus an original analysis in the Context section below.). Also, I made a cool graph of all of the exoplanets we’ve found so far, that’s below too. So, here’s a second bonus published research synopsis in as many weeks: [...]

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