Haider and Pandya Geoscience Letters (2015) 2:8 DOI 10.1186/s40562-015-0023-2 RESEARCH LETTER Open Access Probing of meteor showers at Mars during the encounter of comet C/2013 A1: predictions for the arrival of MAVEN/Mangalyaan Syed A Haider1* and Bhavin M Pandya2 Abstract We have estimated (1) production rates, (2) ion and electron densities of meteor ablation and (3) ionization for different masses and velocities of meteoroids when comet C/2013 A1 crossed the orbit of Mars on 19 October, 2014 at 18:27 UT. Meteor ablations of small masses < 10−4 g have created a broad layer between altitude ~ 90 km and 110 km. The meteoroids of large masses ≥ 10−4 g are burnt at around 60–90 km well below the main ionization peak at altitude ~160 km produced in the nighttime by solar wind particle impact. The production rates + + + + + + + + + + + + + and densities of 15 metallic ions (Mg ,Fe ,Si ,MgO , FeO , SiO , MgCO2, MgO2, FeCO2, FeO2, SiCO2, SiO2, MgN2, + + FeN2, and SiN2) have been computed self-consistently between altitudes 50 km and 150 km. The twelve major peaks in the Ion Mass Spectra (IMS) are predicted by our model calculations. Our predicted ion and electron density profiles of metals provide benchmark values that can be observed by plasma probes onboard Mars Express (MEX), Mars Atmosphere and Volatile Evolution (MAVEN) and Mangalyaan. Introduction measure electron density profiles during this event. MEX The comet C/2013 A1 was discovered on 3 January, 2013 is orbiting around Mars since April, 2004 (cf. [2]). It car- at Siding Spring Observatory using Uppsala Southern ries Mars Express radio science experiment (MaRS) which Schmidt Telescope (http://ssd.jpl.nasa.gov/sbdb.cgi). It can observe electron density profiles in the atmosphere passed from the environment of Mars at minimum dis- when the comet C/2013 A1 crossed the orbit of Mars. tance ~ 134000 km (equal to 0.00059 AU) on 19 October, The Opportunity and Curiosity rovers landed on Mars on 2014 at nighttime [1]. The closest approach of this comet 25 January, 2004 and 6 August, 2013 respectively [3,4]. with Mars is shown in Figure 1. Mangalyaan and MAVEN Their panoramic imaging cameras can also detect light of have been explored into Mars environment on 5 and 18 meteor bombardments in the environment of Mars during November, 2013 respectively. Both missions reached in its encounter with this comet. the orbit of Mars during last week of September, 2014. In this paper we have estimated production rates, ion The Neutral Gas Ion Mass Spectrometer (NGIMS) on- and electron densities for meteor ionization of different board MAVEN has sampled the compositions of Mars at- masses and velocities of meteoroids at solar zenith angle mosphere and observed eight metals (i.e. Mg, Fe, Na, K, (SZA) 110°. Our calculation suggests that two broad me- Mn, Ni, Cr and Zn) after the close encounter with C/ teoric layers can be formed in the middle ionosphere 2013A1 (mars.nasa.gov./comets/siding spring). The Mar- during the encounter of the comet C/2013 A1 with the tian Exospheric Neutral Composition Analyzer (MENCA) atmosphere of Mars. It is found that the meteor ablation − onboard Mangalyaan should also measure the mass dens- of small masses < 10 4 g would occur between altitude ities of cometary dust in the Martian environment 90 km and 110 km where the free molecular path is sev- (www.isro.org/mars/updates.aspx). Both missions do not eral orders larger than the meteoroid size. This is known carry radio occultation experiment. Therefore, they cannot as micrometeoroids [5]. The meteoroids of large − masses ≥ 10 4 g will penetrate deeper into the atmos- * Correspondence: [email protected] phere and burn at altitude range 60 – 90 km. The pre- 1Space and Atmospheric Sciences, Physical Research Laboratory, Navrangpura, Ahmedabad, India dicted rate of ion formation and ion/electron density of Full list of author information is available at the end of the article © 2015 Haider and Pandya. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. Haider and Pandya Geoscience Letters (2015) 2:8 Page 2 of 13 Figure 1 Comet C/2013 A1 is crossing Mars orbit from a solar distance 1.403 AU on October 19, 2014. Simulated view of comets and position of Sun, Earth, Mars, Mercury and Venus are shown in these figures (http://ssd.jpl.nasa.gov/sbdb.cgi). − meteors of all masses increases with velocities of meteor- densities ~ (0.5–1.4) × 104 cm 3 at altitudes between oids. During the meteor showers the ion and electron 80 km and 105 km, presumably due to ionization of me- density are increased by several orders of magnitude in teoric atoms. Using these profiles they examined TEC in the middle ionosphere of Mars. the lower ionosphere of Mars and found that maximum values of TEC occurred on 21 January and 23 May 2005, Earlier measurements of meteoric layers on mars when comets 2007 PL42 and 4015 Wilson-Harrington The presence of meteoric layers at about 80 km was first intersected the orbit of Mars from close distances of reported in the night time from the observations made by 1.49 AU and 1.17 AU, respectively. The TEC values were Mars 4 and Mars 5 [6]. Later a meteor observing campaign increased by a factor of 5–7 on these days. Pandya and was carried out by Panoramic camera (Pancam) onboard Haider [12] associated this significant increase with the Mars Exploration Rover (MER) Spirit which detected two meteor showers that were produced when Mars crossed Martian showers on 18 November and 27 October 2005 the dust stream left along the orbits of these comets. when comet Halley and 2001/R1 LONEOS intersected the These meteor showers were detected on Mars at dif- orbit of Mars from a close distance 0.067 AU and ferent locations and at different times. The meteor 0.001 AU, respectively. Domokos et al. [7] analyzed night- shower of 21 January 2005 was observed at SZA = time Pancam observations and estimated an upper limit of 74.3°, latitude 77.7°N and longitude 197.2°E during − − − meteoroid flux 1.2× 10 19 cm 2 s 1 of mass larger than 4 g. summer season (Ls = 147.4°).Themeteorshowerof Molina-Cuberos et al. [8] used micro sized meteoroid fluxes 23 May 2005 was detected in the autumn season at Ls = − − − − − − 10 19 to10 17 cm 2 s 1 for masses ~10 4 to 10 10 g and cal- 216.2°, SZA = 84.9°, latitude = 65.1°N and longitude 20.2°E. − culated maximum electron density ~2 × 104 cm 3 and 3 × Since 2004 MaRS experiment has observed 557 electron − 102 cm 3 during the daytime and nighttime ionosphere of density profiles in the daytime and nighttime ionosphere of Mars at altitudes 85 km and 83 km respectively. Mars [13,14]. Patzold et al. [13] observed meteoroid layers Mars Global Surveyor (MGS) has observed 5600 electron in 8% electron density profiles (i.e. 10 of 120 electron density density profiles from radio science experiment during the profiles) of MEX measurementsduringthedaytimeiono- period 24 December 1998 to 9 June 2005 [9-11]. Withers sphere. Recently Haider et al. [15] have identified meteoric et al. [10] found meteoric layers in 71 out of these 5600 layers in two electron density profiles of MEX observations electron density profiles. They have reported mean peak carried out in the nighttime ionosphere also, one on 22 − electron density (1.33 ± 0.5) × 104 cm 3 in the meteoric August and the other on 25 September, 2005. layer at a mean altitude of 91.7 ± 4.8 km. Their analysis sug- gests that the characteristics of these meteoric layers vary Methods with season, SZA and latitude. Later Pandya and Haider Modeling and input parameters [12] analyzed 1500 MGS electron density profiles to study Recently MEX has observed three ionization peaks in the physical characteristics of meteoric plasma layers over the nighttime ionosphere of Mars at altitudes ~80- Mars during the period January-June 2005. They 100 km, 120 km and 160 km, which were reproduced by found that 65 electron density profiles out of these model calculation due to impact of meteoroid, solar 1500 profiles were strongly perturbed with peak wind proton (≤10 KeV) and electron (≤1KeV) Haider and Pandya Geoscience Letters (2015) 2:8 Page 3 of 13 respectively (cf. [15]). We have used this model to calcu- scaled meteoroid fluxes of Figure 2 to Martian orbit -0.5 late the production rates and electron densities at SZA according to φm = φe xRm [21], where φe and φm 110° due to impact of micrometeoroids and meteoroids of are the particle fluxes of dust in the orbit of Earth different masses and velocities. These calculations are car- and Mars respectively, Rm is the distance of Mars ried out between altitudes of 50 km and 150 km for me- from the sun in AU. The solar wind electron-proton- teor ablation that occurred on 19 October, 2014 during hydrogen impact ionizations are not included in this the encounter of comet/2013 A1 with Mars atmosphere. model calculation because they are important above We have considered ablation of different meteoroids 120 km (cf. [15]). − − of masses 10 9 ≤ m<101 gforfluxes106 ≤ f<10 Our chemical model depends on the temperature and − − − 16 cm 2 s 1 at interval of 10 g, where m and f are density of the atmosphere.