1. Bright features in Neptune on 2013-2015 from ground-based observations with small (40 cm) and large telescopes (10 m)
- Author
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Hueso, Ricardo, Delcroix, Marc, Christoph Baranec, Sánchez-Lavega, Agustín, María Gómez-Forrellad, Josep, Félix Rojas, Jose, Luszcz-Cook, Statia, Pater, Imke, Kleer, Katherine, Colas, François, Guarro, Joan, Goczynski, Peter, Jones, Paul, Kivits, Willem, Maxson, Paul, Phillips, Michael, Sussenbach, John, Wesley, Anthony, Hammel, Heidi B., Pérez-Hoyos, Santiago, Mendikoa, Iñigo, Riddle, Reed, Law, Nicholas M., Sayanagi, Kunio, University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), Société Astronomique de France (SAF), Institute for Astronomy, University of Hawaii, Fundacio Observatori Esteve Duran, American Museum of National History, University of California (UCBerkeley), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, International Outer Planets Watch, Planetary Virtual Observatory Laboratory, Association of Universities for Research in Astronomy, California Institute of Technology, University of North Carolina, Hampton University in Virginia, and Henry, Florence
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[PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph] ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
International audience; Observations of Neptune over the last few years obtained with small telescopes (30-50 cm) have resulted in several detections of bright features on the planet. In 2013, 2014 and 2015, different observers have repeatedly observed features of high contrast at Neptune's mid-latitudes using long-pass red filters. This success at observing Neptune clouds with such small telescopes is due to the presence of strong methane absorption bands in Neptune's spectra at red and near infrared wavelengths; these bands provide good contrast for elevated cloud structures. In each case, the atmospheric features identified in the images survived at least a few weeks, but were essentially much more variable and apparently shorter-lived, than the large convective system recently reported on Uranus [de Pater et al. 2015]. The latest and brightest spot on Neptune was first detected on July 13th 2015 with the 2.2m telescope at Calar Alto observatory with the PlanetCam UPV/EHU instrument. The range of wavelengths covered by PlanetCam (from 350 nm to the H band including narrow-band and wide-band filters in and out of methane bands) allows the study of the vertical cloud structure of this bright spot. In particular, the spot is particularly well contrasted at the H band where it accounted to a 40% of the total planet brightness. Observations obtained with small telescopes a few days later provide a good comparison that can be used to scale similar structures in 2013 and 2014 that were observed with 30-50 cm telescopes and the Robo-AO instrument at Palomar observatory. Further high-resolution observations of the 2015 event were obtained in July 25th with the NIRC2 camera in the Keck 2 10-m telescope. These images show the bright spot as a compact bright feature in H band with a longitudinal size of 8,300 km and a latitudinal extension of 5,300 km, well separated from a nearby bright band. The ensemble of observations locate the structure at -41º latitude drifting at about 24.27º/day or -92.3 m/s consistently with the zonal winds. This work demonstrates excellent opportunities for pro-am collaboration in the study of Neptune and the value of nearly continuous monitoring of the planet by a broad network of amateur collaborators.
- Published
- 2015