One or more bound planets per Milky Way star from microlensing observations

Cassan, A.; Kubas, D.; Beaulieu, J. P.; Dominik, M.; Horne, K.; Greenhill, J.; Wambsganß, J.; Menzies, John; Williams, A.; Jørgensen, U. G.; Udalski, A.; Bennett, D. P.; Albrow, M. D.; Batista, V.; Brillant, S.; Caldwell, J. A. R.; Cole, A. A.; Coutures, C.; Cook, K. H.; Dieters, S.; Prester, D. Dominis; Donatowicz, J.; Fouqué, P.; Hill, K.; Kains, N.; Kane, Stephen R.; Marquette, J. B.; Martín, Roland; Pollard, K. R.; Sahu, Kailash C.; Vinter, C.; Warren, D.; Watson, Bob; Zub, M.; Sumi, T.; Szymański, M. K.; Kubiak, M.; Poleski, R.; Soszyński, I.; Ulaczyk, K.; Pietrzyński, G.; Wyrzykowski, Ł.

doi:10.1038/nature10684

Cited by 542 publications

(534 citation statements)

References 27 publications

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“…Such a discovery, while dramatic, would not be completely unexpected, given the recent accumulating evidence for the presence, around many WDs, of dust-and-gas disks, and ongoing accretion of rocky debris (see Section 1.2). If snowline-region Neptunes exist around many stars, as indicated by microlensing planet surveys (Gould et al 2010;Cassan et al 2012;Shvartzvald et al 2014) and inward migration of such planets is frequent in the protoplanetary phase (e.g. Trilling et al 1998;Ida & Lin 2008), it is conceivable that post-stellar migration of surviving outer planets could frequently occur around WDs.…”

Section: Discussionmentioning

confidence: 99%

Kepler and the seven dwarfs: detection of low-level day-time-scale periodic photometric variations in white dwarfs

Maoz

Mazeh

McQuillan

2014

Monthly Notices of the Royal Astronomical Society

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We make use of the high photometric precision of Kepler to search for periodic modulations among 14 normal (DA-and DB-type, likely non-magnetic) hot white dwarfs (WDs). In five, and possibly up to seven of the WDs, we detect periodic, ∼ 2 hr to 10 d, variations, with semi-amplitudes of 60-2000 ppm, lower than ever seen in WDs. We consider various explanations: WD rotation combined with magnetic cool spots; rotation combined with magnetic dichroism; rotation combined with hot spots from an interstellar-medium accretion flow; transits by size ∼ 50-200 km objects; relativistic beaming due to reflex motion caused by a cool companion WD; or reflection/reradiation of the primary WD light by a brown-dwarf or giant-planet companion, undergoing illumination phases as it orbits the WD. Each mechanism could be behind some of the variable WDs, but could not be responsible for all five to seven variable cases. Alternatively, the periodicity may arise from UV metal-line opacity, associated with accretion of rocky material, a phenomenon seen in ∼ 50% of hot WDs. Nonuniform UV opacity, combined with WD rotation and fluorescent optical re-emission of the absorbed UV energy, could perhaps explain our findings. Even if reflection by a planet is the cause in only a few of the seven cases, it would imply that hot Jupiters are very common around WDs. If some of the rotation-related mechanisms are at work, then normal WDs rotate as slowly as do peculiar WDs, the only kind for which precise rotation measurements have been possible to date.

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Section: Discussionmentioning

confidence: 99%

Kepler and the seven dwarfs: detection of low-level day-time-scale periodic photometric variations in white dwarfs

Maoz

Mazeh

McQuillan

2014

Monthly Notices of the Royal Astronomical Society

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“…Gould et al (2010) estimated the planet abundance beyond the snow line based on six events and found that they are 7 times more likely than that at close orbits of 1 AU. Cassan et al (2012) used 6 yr of PLANET collaboration data to constrain the cool planetary mass function for masses -…”

Section: Introductionmentioning

confidence: 99%

Ogle-2012-BLG-0724lb: A Saturn-Mass Planet Around an M Dwarf

Hirao

Udalski

Sumi

et al. 2016

ApJ

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We report the discovery of a planet by the microlensing method, OGLE-2012-BLG-0724Lb. Although the duration of the planetary signal for this event was one of the shortest seen for a planetary event, the anomaly was well covered thanks to high-cadence observations taken by the survey groups OGLE and MOA. By analyzing the light curve, this planetary system is found to have a mass ratio ( ) = ´-q 1.58 0.15 10 3 . By conducting a Bayesian analysis, we estimate that the host star is an M dwarf with a mass of . Because the lens-source relative proper motion is relatively high, future highresolution images would detect the lens host star and determine the lens properties uniquely. This system is likely a Saturn-mass exoplanet around an M dwarf, and such systems are commonly detected by gravitational microlensing. This adds another example of a possible pileup of sub-Jupiters ( )in contrast to a lack of Jupiters ( -M 1 2 Jup ) around M dwarfs, supporting the prediction by core accretion models that Jupitermass or more massive planets are unlikely to form around M dwarfs.

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“…Eighteen years later, we have "lost" Pluto but, on the other hand, we have gained a thousand planets planets in orbit around other stars and this number appears far from being final. The current statistical estimates seem to indicate that, on average, every star in our Galaxy hosts at least one planetary companion (Cassan et al 2012). Given that the number of stars in the Milky Way is estimated to be ∼10 11 , planetary scientists are expected to be kept busy in the next years!…”

Section: Overviewmentioning

confidence: 97%

Spectroscopy of planetary atmospheres in our Galaxy

Tinetti

Encrenaz

Coustenis

2013

Astron Astrophys Rev

123

110

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About 20 years after the discovery of the first extrasolar planet, the number of planets known has grown by three orders of magnitude, and continues to increase at neck breaking pace. For most of these planets we have little information, except for the fact that they exist and possess an address in our Galaxy. For about one third of them, we know how much they weigh, their size and their orbital parameters. For less than 20, we start to have some clues about their atmospheric temperature and composition. How do we make progress from here?We are still far from the completion of a hypothetical Hertzsprung-Russell diagram for planets comparable to what we have for stars, and today we do not even know whether such classification will ever be possible or even meaningful for planetary objects. But one thing is clear: planetary parameters such as mass, radius and temperature alone do not explain the diversity revealed by current observations. The chemical composition of these planets is needed to trace back their formation history and evolution, as happened for the planets in our Solar System. As in situ measurements are and will remain off-limits for exoplanets, to study their chemical composition we will have to rely on remote sensing spectroscopic observations of their gaseous envelopes.

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One or more bound planets per Milky Way star from microlensing observations

Cited by 542 publications

References 27 publications

Kepler and the seven dwarfs: detection of low-level day-time-scale periodic photometric variations in white dwarfs

Kepler and the seven dwarfs: detection of low-level day-time-scale periodic photometric variations in white dwarfs

Ogle-2012-BLG-0724lb: A Saturn-Mass Planet Around an M Dwarf

Spectroscopy of planetary atmospheres in our Galaxy

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