DISRUPTIVE PLANETS

Fig. 1:

The TRAPPIST-1 planetary system is a favorable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the James Webb Space Telescope. A possible obstacle to this technique could come from the photospheric heterogeneity of the host star that could affect planetary signatures in the transit transmission spectra. To constrain further this possibility, we routinely perform an extensive photometric monitoring of TRAPPIST-1 transits in the near-IR J band (1.2 micron)  and in the NB2090 band (2.1 micron). In our analysis of these data, we use a special strategy aiming to ensure uniformity in our measurements and robustness in our conclusions. This special attention is motivated by the inherent complexity of ground-based near-IR data reduction appearing as correlations of deduced transit depths with photometric aperture sizes and comparison stars. Here, you can see period-folded transits of TRAPPIST-1 b-g planets. Individual measurements are presented in colored circles and white circles are 7~min binned values. The solid black line represents the best-fit model.

Fig. 2:

The ground-based and space exoplanet transit surveys have observed a substantial portion of the sky in an attempt to find new transiting planets. However, most of these surveys find challenging reliable detection of transit signals in very dense parts of the Galactic plane because of problems associated with blending of the stars. Blending complicates the detection of transit signals and can significantly increase the rate of false-positive exoplanet candidates. Therefore, there is an opportunity for a dedicated exoplanet survey that will explore the Galactic plane with sufficient spatial resolution and cadence to find new transiting exoplanets. Motivated by this, we initiated the Galactic Plane eXoplanet (GPX) survey. GPX is a multinational project involving a collaboration of amateur and professional astronomers from Europe, Asia, and North America.  The main goal of GPX is to survey high-density star fields of the Galactic plane with moderately high image resolution of 2 arcsec/pixel in order to find new transiting gas giant exoplanets and transiting brown dwarfs. Left: Image of a 210 x 210 arcsec^2 region around GPX-1 (V=12 mag), obtained with a telescope with an image scale of 1.85 arcsec/pixel. Note the bright star HD 15691 (V=9 mag) located 42 arcsec SW from GPX-1. Middle: TESS 210 x 210 arcsec^2 (10 x 10 pixel^2) image of the same Field of View. Right: GPX discovery light curve as obtained with the RASA 11" wide-field telescope and folded with ~1.75 day period. The solid black line represents the best-fit transit model.

Credit: Daniel Padron

Fig. 3: One of the most significant goals of modern science is establishing whether life exists around other suns. The most direct path towards its achievement is the detection and atmospheric characterization of terrestrial exoplanets with potentially habitable surface conditions. The nearest ultracool dwarfs (UCDs), i.e. very-low-mass stars and brown dwarfs with effective temperatures lower than 2700 K, represent a unique opportunity to reach this goal within the next decade. The potential of the transit method for detecting potentially habitable Earth-sized planets around these objects is drastically increased compared to Earth-Sun analogs. Furthermore, only a terrestrial planet transiting a nearby UCD would be amenable for a thorough