Io's hot spots in the near-infrared detected by LEISA during the New Horizons flyby

2014 ◽  
Vol 119 (10) ◽  
pp. 2222-2238 ◽  
Author(s):  
Constantine C. C. Tsang ◽  
Julie A. Rathbun ◽  
John R. Spencer ◽  
Brigette E. Hesman ◽  
Oleg Abramov
Keyword(s):  
1997 ◽  
Vol 24 (20) ◽  
pp. 2439-2442 ◽  
Author(s):  
Rosaly Lopes-Gautier ◽  
A. G. Davies ◽  
R. Carlson ◽  
W. Smythe ◽  
L. Kamp ◽  
...  

2002 ◽  
Vol 12 ◽  
pp. 614-617
Author(s):  
Ashley Gerard Davies ◽  
Sylvain Douté

AbstractThe Near Infrared Mapping Spectometer (NIMS) on the Galileo spacecraft has been observing the volcanic Jovian satellite Io at regular intervals since June 1996. These infrared observations have allowed detailed mapping of the distribution and grain size of sulfur dioxide on Io’s surface, identification of volcanic centers, mapping of the distribution of hot spots, and investigations into the style and evolution of individual volcanic eruptions.


1997 ◽  
Vol 159 ◽  
pp. 349-350
Author(s):  
J. K. Kotilainen

AbstractWe discuss NIR imaging of the starburst galaxy NGC 1808. The circumnuclear continuum emission shows no morphological change with wavelength and most of it is produced by an evolved bulge population, not by red supergiants or dust. The line emission arises from distinct hot spots. From comparison of Brγ and Hα fluxes, we derive extinction Av = 3–5 toward the hot spots. From modeling of the line and continuum luminosities, we derive a star-formation rate of 0.1–0.6 M⊙ yr–1 and SN rate ~ 0.4–11 × 10–3 yr–1 per hot spot. The age of the burst is 8–17 Myr for the hot spots and ~ 40 Myr for the nucleus. Finally, evidence for and against hidden Seyfert activity in NGC 1808 is discussed.


2021 ◽  
Vol 163 (1) ◽  
pp. 2
Author(s):  
Ashley Gerard Davies

Abstract Between 1996 and 2001, the Galileo Near-Infrared Mapping Spectrometer (NIMS) obtained 190 observations of the volcanic Jovian moon Io. Rathbun et al. (2018) [Astron. J., 156, 207] published a list of 287 measurements of 3.5 μm spectral radiance from some of Io’s active volcanoes, derived from a subset of the NIMS data. However, the spectral radiances reported by Rathbun et al. are lower, in some cases by multiple orders of magnitude, than other analyses of the same observations and spectral radiances derived from contemporaneous ground-based data. In many cases, the Rathbun et al. hot-spot radiances are underreported by a factor of π, likely due to a mistake in unit conversion. For a small number of powerful hot spots, additional discrepancies appear to be the result of poor fits to data limited in wavelength range by NIMS detector saturation and a methodology that discards short-wavelength NIMS data that otherwise would have provided more robust temperature model fits.


2018 ◽  
Vol 613 ◽  
pp. A50 ◽  
Author(s):  
I. Carleo ◽  
S. Benatti ◽  
A. F. Lanza ◽  
R. Gratton ◽  
R. Claudi ◽  
...  

Context. Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique. Aims. We attempt to definitively discriminate the nature of the RV variations for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion. Methods. We compare VIS data with high precision RVs in the near-infrared (NIR) range by using the GIANO–B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO–B and HARPS–N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does not change at different wavelengths, while stellar activity induces wavelength-dependent RV variations, which are significantly reduced in the NIR range with respect to the VIS. Results. The NIR radial velocity measurements from GIANO–B and IGRINS show an average amplitude of about one quarter with respect to previously published VIS data, as expected when the RV jitter is due to stellar activity. Coeval multi-band photometry surprisingly shows larger amplitudes in the NIR range, explainable with a mixture of cool and hot spots in the same active region. Conclusions. In this work, the claimed massive planet around BD+20 1790 is ruled out by our data. We exploited the crucial role of multi-wavelength spectroscopy when observing young active stars: thanks to facilities like GIARPS that provide simultaneous observations, this method can reach its maximum potential.


2020 ◽  
Vol 10 (8) ◽  
pp. 2752
Author(s):  
Yoko Hoshi

In 1977, Jöbsis first described the in vivo application of near-infrared spectroscopy (NIRS) [...]


1998 ◽  
Vol 103 (E10) ◽  
pp. 23023-23041 ◽  
Author(s):  
M. Roos-Serote ◽  
P. Drossart ◽  
T. Encrenaz ◽  
E. Lellouch ◽  
R. W. Carlson ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3082 ◽  
Author(s):  
Zhanshan Sun ◽  
Yuejun Zheng ◽  
Yunqi Fu

Here, we report a graphene-based electric field enhancement structure achieved by several adjacent metal nanoribbons which form the hot spots of the electric field and thus promote the absorption of the single layered graphene below the hot spots. Based on the tunability of the graphene’s Fermi level, the absorption rate can be modulated from near 100% to 35% under low electrostatic gating, leading to a 20 dB modulation depth of reflectance. Compared with the existing near infrared spatial light modulators such as optical cavities integrated with graphene and other structures utilizing patterned or highly doped graphene, our design has the advantages of strong optical field enhancement, low power dissipation and high modulation depth. The proposed electro-optic modulator has a promising potential for developing optical communication and exploiting big data interaction systems.


1994 ◽  
Vol 159 ◽  
pp. 461-461
Author(s):  
L.E. Tacconi-Garman ◽  
A. Krabbe ◽  
A. Sternberg ◽  
R. Genzel

We report 0.6″ res. J, H, and K and 1.5″ res. imaging of 2.17 μm HI Brγ and 2.12 μm H2 1-0 S(1) line emission towards the nucleus of the starburst galaxy NGC 1808. In the K-band data we (partially) resolve the nucleus and see several small knots in the circumnuclear region. Further, our JHK continuum images show that a large fraction of the near infrared light in NGC 1808 is produced in young star forming clusters. The Brγ emission originates from a compact nuclear source and from several distinct emission knots in the circumnuclear region. These knots are spatially well correlated with a family of compact radio sources, but uncorrelated with the optical “hot spots”. We propose that the Brγ knots trace the actual sites of starburst activity, while the optical hot spots are just directions of low foreground extinction.We use our data together with radio and far-infrared continuum emission measurements to constrain the parameters of the individual starburst sites in NGC 1808. The data suggest that the starbursts are unsynchronized and prolonged (5 × 106–5 × 107 yrs). The star formation rates in the active sites range from ∼0.1 to ∼0.6 M⊙ yr−1, and the present rapid rate of star-formation in NGC 1808 can be maintained for at most another ∼7 × 107 yrs.Portions of this work are presently in press (Krabbe, Sternberg, and Genzel 1993), and a second paper is in preparation (Tacconi-Garman et al. 1993).


2013 ◽  
Vol 8 (S299) ◽  
pp. 149-150
Author(s):  
Yukako Aimi ◽  
Misato Fukagawa ◽  
Tomonori Yasuda ◽  
Takuya Yamashita ◽  
Kouji Kawabata ◽  
...  

AbstractTemporal structural changes of protoplanetary disks surrounding T Tauri stars (TTSs) can cause magnitude variations of TTSs. On the other hand, variability is also expected due to cool spots and/or hot spots on the surface of the star, thus it is important to distinguish the causes of the observed variability. Our sample consists of 23 TTSs (22 classical T Tauri stars, 1 weak-lined T Tauri star) and 4 Herbig Ae/Be stars. The observations were performed over a period of about 3 months in the V, J, and KS band, simultaneously. We detected variability for all stars in the three bands (>0.05 mag in V, >0.09 mag in J, >0.09 mag in KS). Color-magnitude relations obtained between V, J, and KS bands suggest that stellar spots are not the only cause of variability for most of our targets. In addition, the data implies that six stellar systems contain larger grains than in the interstellar medium if the variability is only caused by extinction due to circumstellar matter.


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