Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005)
International audience Context: The planets Uranus and Neptune with small apparent diameters are primary calibration standards. Aims: We investigate their variability at ~90 GHz using archived data taken with the IRAM 30 m telescope during the 20 year period 1985 to 2005. Methods: We calibrate the p...
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ftccsdartic:oai:HAL:hal-03732934v1 2023-11-05T03:45:04+01:00 Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) Kramer, Carsten Moreno, Raphaël Greve, A. Physikalisches Institut, Universität zu Köln Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) 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 Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) Pôle Planétologie du LESIA Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) Instituto de Radio Astronomía Milimétrica (IRAM) Institut de RadioAstronomie Millimétrique (IRAM) Centre National de la Recherche Scientifique (CNRS) 2008 https://hal.science/hal-03732934 https://doi.org/10.1051/0004-6361:20077705 en eng HAL CCSD EDP Sciences info:eu-repo/semantics/altIdentifier/arxiv/0801.4452 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20077705 hal-03732934 https://hal.science/hal-03732934 ARXIV: 0801.4452 BIBCODE: 2008A&A.482.359K doi:10.1051/0004-6361:20077705 ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.science/hal-03732934 Astronomy and Astrophysics - A&A, 2008, 482, pp.359-363. ⟨10.1051/0004-6361:20077705⟩ [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] info:eu-repo/semantics/article Journal articles 2008 ftccsdartic https://doi.org/10.1051/0004-6361:20077705 2023-10-07T23:00:29Z International audience Context: The planets Uranus and Neptune with small apparent diameters are primary calibration standards. Aims: We investigate their variability at ~90 GHz using archived data taken with the IRAM 30 m telescope during the 20 year period 1985 to 2005. Methods: We calibrate the planetary observations against non-variable secondary standards (NGC 7027, NGC 7538, W3OH, K3-50A) observed almost simultaneously. Results: Between 1985 and 2005, the viewing angle of Uranus changed from south-pole to equatorial. We find that the disk brightness temperature declines by almost 10% (~2sigma) over this time span indicating that the south-pole region is significantly brighter than average. Our finding is consistent with recent long-term radio observations at 8.6 GHz. Both data sets show a rapid decrease of the Uranus brightness temperature during 1993, indicating a temporal, planetary scale change. We do not find indications for a variation of Neptune's brightness temperature at the 8% level. Conclusions: If Uranus is to be used as a calibration source, and if accuracies better than 10% are required, the Uranus sub-earth point latitude needs to be taken into account. Article in Journal/Newspaper South pole Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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ftccsdartic |
language |
English |
topic |
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] |
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[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Kramer, Carsten Moreno, Raphaël Greve, A. Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
topic_facet |
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] |
description |
International audience Context: The planets Uranus and Neptune with small apparent diameters are primary calibration standards. Aims: We investigate their variability at ~90 GHz using archived data taken with the IRAM 30 m telescope during the 20 year period 1985 to 2005. Methods: We calibrate the planetary observations against non-variable secondary standards (NGC 7027, NGC 7538, W3OH, K3-50A) observed almost simultaneously. Results: Between 1985 and 2005, the viewing angle of Uranus changed from south-pole to equatorial. We find that the disk brightness temperature declines by almost 10% (~2sigma) over this time span indicating that the south-pole region is significantly brighter than average. Our finding is consistent with recent long-term radio observations at 8.6 GHz. Both data sets show a rapid decrease of the Uranus brightness temperature during 1993, indicating a temporal, planetary scale change. We do not find indications for a variation of Neptune's brightness temperature at the 8% level. Conclusions: If Uranus is to be used as a calibration source, and if accuracies better than 10% are required, the Uranus sub-earth point latitude needs to be taken into account. |
author2 |
Physikalisches Institut, Universität zu Köln Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) 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 Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) Pôle Planétologie du LESIA Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) Instituto de Radio Astronomía Milimétrica (IRAM) Institut de RadioAstronomie Millimétrique (IRAM) Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Kramer, Carsten Moreno, Raphaël Greve, A. |
author_facet |
Kramer, Carsten Moreno, Raphaël Greve, A. |
author_sort |
Kramer, Carsten |
title |
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
title_short |
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
title_full |
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
title_fullStr |
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
title_full_unstemmed |
Long-term observations of Uranus and Neptune at 90 GHz with the IRAM 30 m telescope. (1985-2005) |
title_sort |
long-term observations of uranus and neptune at 90 ghz with the iram 30 m telescope. (1985-2005) |
publisher |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.science/hal-03732934 https://doi.org/10.1051/0004-6361:20077705 |
genre |
South pole |
genre_facet |
South pole |
op_source |
ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.science/hal-03732934 Astronomy and Astrophysics - A&A, 2008, 482, pp.359-363. ⟨10.1051/0004-6361:20077705⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/0801.4452 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20077705 hal-03732934 https://hal.science/hal-03732934 ARXIV: 0801.4452 BIBCODE: 2008A&A.482.359K doi:10.1051/0004-6361:20077705 |
op_doi |
https://doi.org/10.1051/0004-6361:20077705 |
_version_ |
1781706422316171264 |