Search Publications

Experimental validation of XRF inversion code for Chandrayaan-1

Narendranath, S.; Sreekumar, P.; Sudhakar, M. +5 more

We have developed an algorithm (x2abundance) to derive the lunar surface chemistry from X-ray fluorescence (XRF) data for the Chandrayaan-1 X-ray Spectrometer (C1XS) experiment. The algorithm converts the observed XRF line fluxes to elemental abundances with uncertainties. We validated the algorithm in the laboratory using high Z elements (20<Z…

Spectral characteristics of the Titanian haze at 1-5 micron from Cassini/VIMS solar occultation data

Courtin, Régis; Kim, Sang J.

We retrieved optical-depth spectra of the Titanian haze in the range 1-5 µm from solar occultation data obtained by the Cassini/Visual Infrared Mapping Spectrometer (VIMS) at altitudes of 59-502 km. Only limited wavelength intervals within this spectral range have been analyzed before. The haze spectra we retrieved are mostly similar to thos…

A model of scattered thermal radiation for Venus from 3 to 5µm

Hueso, R.; Sánchez-Lavega, A.; García Muñoz, A. +2 more

Thermal radiation becomes a prominent feature in the continuum spectrum of Venus longwards of ∼3µm. The emission is traceable to the upper cloud and haze layers in the planet's mesosphere. Venus' thermal radiation spectrum is punctuated by CO₂ bands of various strengths probing into different atmospheric depths. It is thus possibl…

Observations of 6-200 µm emission of the Ophiuchus cloud LDN 1688

Juvela, M.; Lemke, D.; Lehtinen, K. +2 more

We examine two positions, ON1 and ON2, within the Ophiuchus cloud LDN 1688 using observations made with the ISO photo-polarimeter (ISOPHOT) instrument aboard the Infrared Space Observatory (ISO) satellite. The data include mid-infrared spectra (∼6-12 µm) and several photometric bands up to 200 µm. The data probe the emission from molec…

Mg II h + k Flux—Rotational Period Correlation for G-type Stars

Bertone, Emanuele; Olmedo, Manuel; Chávez, Miguel +1 more

We present an analysis of the correlation between the mid-UV Mg II h and k emission lines and measured rotational periods of G-type stars. Based on IUE and HST high resolution spectra of a sample of 36 stars, we derive an exponential function that best represents the correlation. We found that the variation of the Mg II h + k fluxes is about a fac…

Differential asteroseismic study of seismic twins observed by CoRoT. Comparison of HD 175272 with HD 181420

Auvergne, M.; Baudin, F.; García, R. A. +13 more

Context. The CoRoT short asteroseismic runs give us the opportunity to observe a large variety of late-type stars through their solar-like oscillations. We report the observation and modeling of the F5V star HD 175272.
Aims: Our aim is to define a method for extracting as much information as possible from a noisy oscillation spectrum.
Me…

Generation mechanism of the whistler-mode waves in the plasma sheet prior to magnetic reconnection

Dandouras, I.; Santolík, O.; Rème, H. +6 more

The whistler-mode waves and electron temperature anisotropy play a key role prior to and during magnetic reconnection. On August 21, 2002, the Cluster spacecrafts encountered a quasi-collisionless magnetic reconnection event when they crossed the plasma sheet. Prior to the southward turning of magnetospheric magnetic field and high speed ion flow,…

Large-scale mapping of the massive star-forming region RCW38 in the [CII] and PAH emission

Nakagawa, T.; Ojha, D. K.; Fukui, Y. +10 more

Aims: We investigate the large-scale structure of the interstellar medium (ISM) around the massive star cluster RCW 38 in the [CII] 158 µm line and polycyclic aromatic hydrocarbon (PAH) emission.
Methods: We carried out [CII] line mapping of an area of ~30' × 15' for RCW 38 by a Fabry-Perot spectrometer on a 100 cm balloon-borne te…

Correction to "Pc2 EMIC waves generated high off the equator in the dayside outer magnetosphere"

Dandouras, I.; Kistler, L. M.; Zhang, J. -C. +3 more

On-Orbit Sensitivity Evolution of the EUV Imaging Spectrometer on Hinode

Mariska, J. T.

Since its launch on 22 September 2006, the EUV Imaging Spectrometer onboard the Hinode satellite has exhibited a gradual decay in sensitivity. Using spectroheliograms taken in the Fe VIII 185.21 Å and Si VII 275.35 Å emission lines in quiet regions near Sun center we characterize that decay. For the period from December 2006 to March 2012, the dec…