[en] Two stellar occultations by the largest satellite of the dwarf planet Haumea, Hi'iaka, were predicted to happen on April, 6th and 16th, 2021. Additional high accuracy astrometric analysis was carried out in order to refine the prediction for April 6th, using several telescopes in the 1.2-m to 2-m range, with the final shadow path crossing North Africa. We successfully detected the first event from TRAPPIST-North telescope at Oukaïmeden Observatory (Morocco). Although it was recorded from only one site, this first detection allowed us to improve the prediction for the second that crossed North America from East to West. We had a good success recording six positive detections and several negative detections that constrain the shape and size of the body. The light curves obtained from the different observatories provide the time at which the star disappears and reappears, which are translated into chords (the projected lines on the sky-plane as observed from each location). Additionally, we carried out a campaign to study Hi'iaka's rotational light-curve, studying the residuals of Haumea's rotational light-curve to a four-order Fourier fit. We obtained the rotational phases at the times of the occultations, which is critical for the analysis of the occultations, given that Hi'iaka is clearly non-spherical. Our preliminary results show that Hi'iaka indeed has a triaxial shape with a larger effective diameter than what has been published so far. The preliminary results and their implications will be discussed in this talk.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Fernández-Valenzuela, Estela; University of Central Florida, Florida Space Institute, Orlando, United States of America
Ortiz, Jose Luis; Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, Granada, Spain
Holler, Bryan; Space Telescope Science Institute, Baltimore, MD, USA
Vara-Lubiano, Monica; Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, Granada, Spain
Morales, Nicolas; Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas, Granada, Spain
Sicardy, Bruno; LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, France
Vachier, Frederic; Institut de mécanique céleste et de calcul des éphémérides, University of Paris, Paris, France
Desmars, Josselin; Institut de mécanique céleste et de calcul des éphémérides, University of Paris, Paris, France ; Institut Polytechnique des Sciences Avancées IPSA, 63 boulevard de Brandebourg, F-94200 Ivry-sur-Seine, France.
Braga-Ribas, Felipe; LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, France ; Observatório Nacional/MCTIC, Rio de Janeiro - RJ, Brazil
Rustamkulov, Zafar; Department of Earth and Planetary Science, Johns Hopkins University, Baltimore, MD, USA
de la Vega, Alex; Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
Warner, Elizabeth; The University of Maryland, College Park, MD, USA
Conti, Dennis; American Association of Variable Star Observers (AAVSO)
Lecacheux, Jean; LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, France
Francini, Richard; Astronomical League and American Association of Variable Star Observers (AAVSO)
Langill, Phil; Rothney Astrophysical Observatory, University of Calgary, Alberta, Canada
Morales, Ruben; University of Calgary, Calgary, Alberta, Canada
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Fraser, Wesley C.; Herzberg Astronomy and Astrophysics Research Centre, National Research Council of Canada
Souami, Damya; LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, France)
