Predictions on the detection of the free-floating planet population with K2 and spitzer microlensing campaigns

Hamolli, Lindita; Paolis, F. De; Hafizi, M.; Nucita, A. A.

doi:10.1134/s1990341317030099

Cited by 23 publications

(4 citation statements)

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“…In this paper, we assume the parallax observation between Euclid and Roman with variations of the FFP mass function referred from Johnson et al (2020), Gould et al (2022), Sumi et al (2023) and try to approach the relationship between the FFP population, event sensitivity, and accuracy of the microlensing parallax measurement. In a similar research, Hamolli et al (2017) simulated the FFP microlensing detectability between Kepler and Spitzer by varying the FFP mass function, but the combination of these two telescopes seems to be not suitable for research on the low-mass FFPs because of the wide separation and low observation cadence.…”

Section: Introductionmentioning

confidence: 99%

The Impact of the Free-floating Planet Mass Function on the Event Rate for Accurate Microlensing Parallax Determination: Application to Euclid and Roman Parallax Observation

Ban

2023

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A microlensing event is mainly used to search for free-floating planets (FFPs). To estimate the FFP mass and distance via the microlensing effect, a microlensing parallax is one of the key parameters. A short duration of FFP microlensing makes it difficult to yield a parallax by the observer’s motion at a recognizable level, so the FFP microlensing parallax is expected on the simultaneous observation by multiple telescopes. Here, we approach the FFP detection by considering a variation in the FFP mass functions and the event rate of accurately measured microlensing parallaxes. We used our FFP microlensing simulator assuming a parallax observation between upcoming space-based missions (Euclid and Roman) with full kinematics. As a result, we confirmed that the event rate of accurately measured microlensing parallaxes (i.e., within a factor of 2 uncertainty) does not simply follow the number of FFPs at a given mass but the ratio of the FFP population per star. This is because the population ratio determines the optical depth for a given mass and potential sources. In addition, we found that the probability of the event that can estimate the FFP mass and distance within a factor of 2 is not so high: ∼40% of Earth-mass, ∼16% of Neptune-mass, and ∼4% of Jupiter-mass FFP events under our criteria. The probability can be improved by some technical approach such as using high cadence and observation in parallax of more than two observers.

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Section: Introductionmentioning

confidence: 99%

The Impact of the Free-floating Planet Mass Function on the Event Rate for Accurate Microlensing Parallax Determination: Application to Euclid and Roman Parallax Observation

Ban

2023

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“…In the case of large values of D ⊥ , the light curves seen from two observers will exhibit noticeable difference in the parallax effect (see Ref. [13] for details). Considering the photometric observations towards the Galactic bulge, by the Earth (OGLE) and the space telescopes (K2C9 and Spitzer), we calculated the probability that a microlensing event is detected by two telescopes simultaneously.…”

Section: π E In Microlensing Events Caused By Ffpsmentioning

confidence: 99%

“…As one can see, the finite source efficiency is increased with α PL , while the efficiency of the orbital parallax, satellite parallax (for the pairs: Earth-K2C9 and Earth-Spitzer) and astrometric shift decreases with increasing α PL (see Refs. [13,20,39,64] for details).…”

Section: θ E In Microlensing Event Caused By Ffpsmentioning

confidence: 99%

“…The mechanical failure of the second of its four reaction wheels in 2013 signaled the conclusion of the primary mission, but heralded the genesis of an extended K2 Mission. It performed the microlensing survey towards the Galactic bulge from April 7 to July 1, 2016 called K2C9 (see [13] and references therein). K2C9 lasted for about 3 months and this observational period overlapped with that of the Spitzer follow-up microlensing project that started in June, 2016.…”

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Free-floating planets in the Milky Way

et al. 2019

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Gravitational microlensing is a powerful method to search for and characterize exoplanets, and it was first proposed by Paczyński in 1986. We provide a brief historical excursus of microlensing, especially focused on the discoveries of free-floating planets (FFPs) in the Milky Way. We also emphasize that, thanks to the technological developments, it will allow to estimate the physical parameters (in particular the mass and distance) of FFPs towards the center of our Galaxy, through the measure of the source finite radius, Earth or satellite parallax, and/or astrometric effects.Mathematics Subject Classification 85-xx · 85-08 IntroductionDiscovery of the extrasolar planets in our Galaxy is one of the most discussed issues in the scientific community. These objects are outside our solar system and have masses smaller than about 0.01M . Their detection is being achieved using different methods and, until now, we have 3824 confirmed exoplanes (see the website http://exoplanet.eu). Most exoplanets are discovered by the Transit method (∼ 74%) and by Radial Velocity method (∼ 20%). A few exoplanets have been detected using the Direct Imaging technique. Until now, only ∼ 2% of exoplanets have been detected through gravitational microlensing.In recent years, several unbound objects with mass possibly as small as a few times that of Jupiter (M J = 9.5 × 10 −4 M ) have been found in many young star-forming region using infrared imaging surveys [1]. These objects are called free-floating planets or also rogue planets, nomads, or orphan planets (see [2] and references therein). Examples of objects of this kind are WISE 0855-0714, about 2.4 pc away from the Earth [3], and Cha 110913-773444 in the Chamaeleon I star-forming region at a distance of about 160 pc. It is difficult to find this kind of objects by infrared imaging at large distances, so we need the development of alternative methods to search for them. The origin of the FFPs is doubtful, and their formation mechanism remains an open theoretical question in astrophysics. One possibility is that they originally formed around a host star and then scattered out from orbit. A second option is that they may form on their own through gas cloud direct collapse, similarly to star formation.Paczyński [4] first envisaged the search of Galactic dark matter in compact form using gravitational lensing method, which happens when a massive object passes close enough to the line of sight to a distant source star. Since the angular separation of the lensed images are of the order of microarcseconds, such phenomena are often called microlensing [5,6]. In his calculations, Paczyński showed that the chance (or optical depth) of a massive object in the Galactic halo to serve as a lens and magnify a background star in nearby galaxy is 10 −6 . Also, he suggested that, based on modern instruments, we could be able to catch such microlensing events by monitoring a dense stellar field with several millions of stars simultaneously. Therefore, several groundbased experiments such as MACHO (Massiv...

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The Exoplanet Handbook

Perryman¹

2018

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Predictions on the detection of the free-floating planet population with K2 and spitzer microlensing campaigns

Cited by 23 publications

References 19 publications

The Impact of the Free-floating Planet Mass Function on the Event Rate for Accurate Microlensing Parallax Determination: Application to Euclid and Roman Parallax Observation

The Impact of the Free-floating Planet Mass Function on the Event Rate for Accurate Microlensing Parallax Determination: Application to Euclid and Roman Parallax Observation

Free-floating planets in the Milky Way

The Exoplanet Handbook

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