J/AJ/158/29 Io's hot spots NIR adaptive optics: 2013-2018 (de Kleer+, 2019)
Io's volcanic activity from time domain adaptive optics observations: 2013-2018.
de Kleer K., de Pater I., Molter E.M., Banks E., Davies A.G., Alvarez C.,
Campbell R., Aycock J., Pelletier J., Stickel T., Kacprzak G.G.,
Nielsen N.M., Stern D., Tollefson J.
<Astron. J., 158, 29-29 (2019)>
=2019AJ....158...29D 2019AJ....158...29D (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Photometry, infrared
Keywords: infrared: planetary systems - methods: observational -
planets and satellites: surfaces
Abstract:
We present measurements of the near-infrared brightness of Io's hot spots
derived from 2 to 5 µm imaging with adaptive optics on the Keck and
Gemini N telescopes. The data were obtained on 271 nights between 2013
August and the end of 2018, and include nearly 1000 detections of over
75 unique hot spots. The 100 observations obtained between 2013 and 2015
have been previously published in de Kleer & de Pater (2016Icar..280..378D 2016Icar..280..378D)
the observations since the start of 2016 are presented here for the first
time, and the analysis is updated to include the full five-year data set.
These data provide insight into the global properties of Io's volcanism.
Several new hot spots and bright eruptions have been detected, and the
preference for bright eruptions to occur on Io's trailing hemisphere noted
in the 2013-2015 data is strengthened by the larger data set and remains
unexplained. The program overlapped in time with Sprint-A/EXCEED and Juno
observations of the Jovian system, and correlations with transient
phenomena seen in other components of the system have the potential to
inform our understanding of the impact of Io's volcanism on Jupiter
and its neutral/plasma environment.
Description:
We observed Io in the near-infrared with adaptive optics on 271 nights
between 2013 August and 2018 July. Observations were made with the NIRI
imager on Gemini N (Hodapp et al. 2003PASP..115.1388H 2003PASP..115.1388H) combined with
the ALTAIR adaptive optics system in Natural Guide Star (NGS) mode, and
with the NIRC2 imager on Keck II also using NGS adaptive optics
(Wizinowich et al. 2000PASP..112..315W 2000PASP..112..315W). The Gemini N data constitute
80% of the total visits, and include images in the L' (3.78 µm) and
K-cont (2.27 µm) filters. The Keck images were taken in a variety of
filters from H-cont (1.58 µm) to Ms (4.67 µm).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 61 75 Overview of hot spots
table2.dat 55 18 *Bright eruptions, 2013-2018
table3.dat 45 32 *High-temperature eruptions, 2013-2018
table4.dat 40 271 Observations
table5.dat 141 980 Hot spot intensities
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Note on table2.dat: All eruptions detected with Imax,Lp>20 GW/µm/sr during
this time period.
Note on table3.dat: All eruptions detected with T>800 K during this period.
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See also:
J/A+A/427/371 : Galilean satellites ephemerides (Lainey+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Site Hot spot
25- 29 F5.1 deg LAT [-70.8/65.1] Latitude, degrees North
31- 35 F5.1 deg LON [6.2/358.3] Longitude, degrees West
37- 39 I3 --- Ndet [1/113] Number of detections
41- 45 F5.1 GW/um/sr Fmean [0.9/555.7]? Mean observed flux density (1)
47- 61 A15 --- Filter Filter (1)
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Note (1): The mean observed flux density Ffilt is given in the Lp filter if
data were available in this filter, and in the Ms filter if no Lp detections
were made. If no detections were made in either broadband filter, detection
in narrowband only is indicated.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Site Hot spot
25 A1 --- n_Site [b] Note on Site (1)
27- 37 A11 "date" Date UT date of peak
39- 41 I3 deg LAT [-71/65] Latitude, degrees North
43- 45 I3 deg LON [128/308] Longitude, degrees West
47 A1 --- l_Imax [>] Limit flag on Imax
48- 50 I3 GW/um/sr Imax [20/500] Brightest L'-band (3.78 µm)
intensity Imax,Lp
52- 53 I2 GW/um/sr e_Imax [2/80]? Uncertainty in Imax
55 A1 --- Ref [cde] Reference (G1)
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Note (1): Nearly all bright eruptions were transient events at sites where
activity was not otherwise detected. Exceptions are Pillan Patera, Loki
Patera, and Marduk Fluctus, which were persistently active but exhibited
spikes in activity; and Kurdalagon Patera, which was not detected prior to
its first eruption but remained detectable afterwards.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Site Hot spot
19- 29 A11 "date" Date UT observation date
31- 34 F4.2 --- mu [0.17/0.98] Emission angle µ
36- 39 I4 K T [800/1440] Temperature (1)
41- 43 I3 K e_T [40/690] Uncertainty in T
45 A1 --- Ref [cde] Reference (G1)
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Note (1): Temperatures are derived from intensities corrected for geometric
foreshortening, and may be overestimated in observations with high emission
angle (µ) if fire fountaining is producing a substantial fraction of the
short-wavelength emission.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "date" Date UT observation date (1)
12- 24 A13 --- Tel Telescope/Instrument
26- 30 F5.1 deg LON [17.7/343.2] Sub-observer longitude, degrees West
(2)
32- 35 F4.1 deg LAT [-3.4/2] Sub-observer latitude, degrees North (2)
37- 40 F4.2 au Dist [4.25/6.19] Earth-Io distance (2)
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Note (1): Data from 2013-08-15 to 2013-08-23 were previously published in
de Pater et al. (2014Icar..242..365D 2014Icar..242..365D); and data from 2013-2015 were previously
published in de Kleer and de Pater (2016Icar..280..378D 2016Icar..280..378D).
Note (2): Sub-observer latitude and longitude, and Earth-Io distance, from JPL
Horizons.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Site Hot spot
25- 35 A11 "date" Date UT observation date
37- 41 F5.1 deg LAT [-73.2/66.4] Latitude, degrees North
43- 45 F3.1 deg e_LAT [0/3.5] Uncertainty in LAT
47- 51 F5.1 deg LON [6.2/359.6] Longitude, degrees West
53- 56 F4.1 deg e_LON [0/13] Uncertainty in LON
58- 62 F5.1 GW/um/sr I-Kc [4/500]? Continuum intensity in Kc filter
(2.27 µm) (1)
64- 68 F5.1 GW/um/sr e_I-Kc [1.3/260]? Uncertainty in I-Kc
70- 74 F5.2 GW/um/sr I-H2O [0.62/27]? Continuum intensity in H20
filter (3.06 µm) (1)
76- 79 F4.2 GW/um/sr e_I-H2O [0.09/5]? Uncertainty in I-H2O
81- 85 F5.2 GW/um/sr I-PAH [0.92/45]? Continuum intensity in PAH
filter (3.29 µm) (1)
87- 90 F4.2 GW/um/sr e_I-PAH [0.14/8]? Uncertainty in I-PAH
92- 97 F6.2 GW/um/sr I-Lp [0.34/330]? Continuum intensity in L'
filter (3.78 µm) (1)
99-104 F6.2 GW/um/sr e_I-Lp [0.15/110]? Uncertainty in I-Lp
106-110 F5.1 GW/um/sr I-BraCont [1.1/100]? Continuum intensity in Brα
filter (3.99 µm) (1)
112-115 F4.1 GW/um/sr e_I-BraCont [0.2/23]? Uncertainty in I-BraCont
117-122 F6.2 GW/um/sr I-Bra [0.83/140]? Continuum intensity in
Brα filter (4.05 µm) (1)
124-128 F5.2 GW/um/sr e_I-Bra [0.12/45]? Uncertainty in I-Bra
130-135 F6.2 GW/um/sr I-Ms [0.85/210]? Continuum intensity in Ms
filter (4.67 µm) (1)
137-141 F5.2 GW/um/sr e_I-Ms [0.15/30]? Uncertainty in I-Ms
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Note (1): All flux densities are corrected for geometric foreshortening. The
continuum intensities are for the full filter centered at the wavelength
in parenthesis.
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Global notes:
Note (G1): Reference as follows:
c = de Pater et al. (2014Icar..242..365D 2014Icar..242..365D);
d = de Kleer et al. (2014Icar..242..352D 2014Icar..242..352D);
e = de Kleer & de Pater (2016Icar..280..378D 2016Icar..280..378D).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 04-Sep-2019