1 00:00:09,110 --> 00:00:08,089 I did a little switcheroo on the title 2 00:00:10,580 --> 00:00:09,120 and you guys sorry i thought i was going 3 00:00:12,589 --> 00:00:10,590 to be in the Astra chemistry session so 4 00:00:15,350 --> 00:00:12,599 i modified it a little bit to make it a 5 00:00:17,840 --> 00:00:15,360 little bit more relevant to that but we 6 00:00:20,269 --> 00:00:17,850 just got a boatload of data from Hubble 7 00:00:22,939 --> 00:00:20,279 Space Telescope on low mass stars that 8 00:00:26,359 --> 00:00:22,949 host planets and I'm going to give you a 9 00:00:31,009 --> 00:00:26,369 little tour of the what we see in those 10 00:00:32,630 --> 00:00:31,019 data ok so first here's how we're going 11 00:00:34,760 --> 00:00:32,640 to do it and I tell you about what 12 00:00:38,090 --> 00:00:34,770 muscles is and you know why we undertook 13 00:00:39,410 --> 00:00:38,100 this survey and then a quick a little 14 00:00:40,700 --> 00:00:39,420 bit about spectra and then we'll get 15 00:00:43,040 --> 00:00:40,710 into the what I think is the most 16 00:00:46,340 --> 00:00:43,050 interesting which is players that we see 17 00:00:47,869 --> 00:00:46,350 in these data and then I will brief 18 00:00:50,380 --> 00:00:47,879 overview what some of the possible 19 00:00:53,330 --> 00:00:50,390 implications of those flares are for 20 00:00:55,790 --> 00:00:53,340 exoplanet atmospheres all right so 21 00:00:58,490 --> 00:00:55,800 starting with muscles all right just 22 00:00:59,869 --> 00:00:58,500 like most acronyms in science 23 00:01:01,369 --> 00:00:59,879 engineering it's pretty contrived and 24 00:01:03,260 --> 00:01:01,379 goes measurements of the ultraviolet 25 00:01:05,000 --> 00:01:03,270 spectral characteristics of low-mass XO 26 00:01:06,380 --> 00:01:05,010 planetary systems so first let me 27 00:01:08,690 --> 00:01:06,390 shorten that a little bit so I can fit 28 00:01:11,450 --> 00:01:08,700 it on the top of the slide and then 29 00:01:13,460 --> 00:01:11,460 let's unpack the two important parts of 30 00:01:14,990 --> 00:01:13,470 this first of all why the ultraviolet 31 00:01:16,760 --> 00:01:15,000 spectral characteristics as opposed to 32 00:01:19,010 --> 00:01:16,770 other parts of the electromagnetic 33 00:01:21,050 --> 00:01:19,020 spectrum and then why low-mass 34 00:01:24,649 --> 00:01:21,060 exoplanetary systems so I'm going to go 35 00:01:26,390 --> 00:01:24,659 in reverse order since its near lunch I 36 00:01:30,260 --> 00:01:26,400 will go ahead and give you this little 37 00:01:31,640 --> 00:01:30,270 introduction to spectral types of stars 38 00:01:36,950 --> 00:01:31,650 even though this is briefly discussed 39 00:01:39,980 --> 00:01:36,960 earlier of course astronomers referred 40 00:01:41,300 --> 00:01:39,990 or classify stars using this lettering 41 00:01:42,740 --> 00:01:41,310 system which doesn't really make that 42 00:01:44,800 --> 00:01:42,750 much sense because it's not ordered by 43 00:01:49,969 --> 00:01:44,810 the alphabet but it has historical 44 00:01:52,340 --> 00:01:49,979 reasons for that and basically these 45 00:01:54,830 --> 00:01:52,350 stars on the left are as you can see the 46 00:01:56,030 --> 00:01:54,840 image k stars are cooler there redder 47 00:01:59,179 --> 00:01:56,040 which means they're cooler they're 48 00:02:01,639 --> 00:01:59,189 smaller the less luminous and as you 49 00:02:03,950 --> 00:02:01,649 know you go to spectral types of a piano 50 00:02:05,480 --> 00:02:03,960 they get bigger and hotter the sons of g 51 00:02:07,190 --> 00:02:05,490 star and the low-mass stars and i'm 52 00:02:10,040 --> 00:02:07,200 talking about our ending k stars and 53 00:02:11,510 --> 00:02:10,050 i'll probably eventually mess up and say 54 00:02:12,790 --> 00:02:11,520 endorse even though i don't want to do 55 00:02:15,190 --> 00:02:12,800 that to you guys because it makes it 56 00:02:16,450 --> 00:02:15,200 like these stars are irregular or 57 00:02:18,970 --> 00:02:16,460 something that they are not a normal 58 00:02:20,710 --> 00:02:18,980 size but it just means that they aren't 59 00:02:23,980 --> 00:02:20,720 they haven't become Giants yet so if I 60 00:02:26,380 --> 00:02:23,990 say m dwarf I mean a regular in star all 61 00:02:27,820 --> 00:02:26,390 right so the reason we care about these 62 00:02:29,290 --> 00:02:27,830 M stars is because basically there's a 63 00:02:33,190 --> 00:02:29,300 lot of them and you all probably seen 64 00:02:36,360 --> 00:02:33,200 this sketch from XKCD and all of the 65 00:02:39,190 --> 00:02:36,370 gray dots on this represent 66 00:02:40,900 --> 00:02:39,200 statistically at least planetary systems 67 00:02:44,320 --> 00:02:40,910 within 60 light-years of Earth that 68 00:02:46,510 --> 00:02:44,330 should be and should have stars that are 69 00:02:49,480 --> 00:02:46,520 smaller than the Sun essentially and the 70 00:02:51,120 --> 00:02:49,490 red points are sun-like stars and the 71 00:02:54,070 --> 00:02:51,130 gray points make up about ninety percent 72 00:02:55,630 --> 00:02:54,080 so by sheer numbers alone we should care 73 00:02:58,300 --> 00:02:55,640 about low mass stars when we think about 74 00:02:59,770 --> 00:02:58,310 planets okay so now you know about the 75 00:03:02,980 --> 00:02:59,780 low-mass part of that title what about 76 00:03:06,730 --> 00:03:02,990 the UV well here is a stellar spectrum I 77 00:03:09,820 --> 00:03:06,740 have modified the scale a little bit so 78 00:03:12,400 --> 00:03:09,830 the black body part of the spectrum is 79 00:03:13,330 --> 00:03:12,410 actually fits on the diagram but we're 80 00:03:15,820 --> 00:03:13,340 actually not gonna talk about the black 81 00:03:18,640 --> 00:03:15,830 body at all instead we're curious about 82 00:03:20,710 --> 00:03:18,650 the UV because photons in the UV have 83 00:03:25,720 --> 00:03:20,720 about the right amount of energy to 84 00:03:29,410 --> 00:03:25,730 split atoms off of molecules oh so for 85 00:03:31,360 --> 00:03:29,420 example you can associate oxygen and we 86 00:03:34,449 --> 00:03:31,370 were also curious about slightly shorter 87 00:03:35,920 --> 00:03:34,459 wavelengths the x-ray and extreme 88 00:03:40,110 --> 00:03:35,930 ultraviolet because these have enough 89 00:03:42,790 --> 00:03:40,120 energy to eject an electron from an atom 90 00:03:43,870 --> 00:03:42,800 and this actually has a big role plays a 91 00:03:46,030 --> 00:03:43,880 big role in heating the upper atmosphere 92 00:03:50,110 --> 00:03:46,040 of planets so that's the ultraviolet 93 00:03:52,210 --> 00:03:50,120 part of this ok so before I go any 94 00:03:54,220 --> 00:03:52,220 further let me just plug our main 95 00:03:56,650 --> 00:03:54,230 spectral data products go fast we 96 00:03:59,050 --> 00:03:56,660 managed to squeeze 30 I mean we managed 97 00:04:02,530 --> 00:03:59,060 to write three very important 98 00:04:04,060 --> 00:04:02,540 informative favors about how we reduce 99 00:04:05,979 --> 00:04:04,070 these data and everything that went into 100 00:04:08,949 --> 00:04:05,989 getting spectra that go all the way from 101 00:04:10,210 --> 00:04:08,959 the x-ray to the infrared and actually 102 00:04:12,280 --> 00:04:10,220 there is a ton that goes into it so the 103 00:04:13,930 --> 00:04:12,290 three papers were necessary and for you 104 00:04:16,180 --> 00:04:13,940 photochemical modelers out there anybody 105 00:04:17,560 --> 00:04:16,190 else who's interested you can find these 106 00:04:19,449 --> 00:04:17,570 spectra by going to that link or 107 00:04:21,640 --> 00:04:19,459 searching muscles spectral catalog which 108 00:04:23,350 --> 00:04:21,650 has the additional benefit of giving you 109 00:04:24,420 --> 00:04:23,360 some interesting google image search 110 00:04:27,659 --> 00:04:24,430 results 111 00:04:30,870 --> 00:04:27,669 oh ok so now let's go on to some more 112 00:04:33,450 --> 00:04:30,880 results basically I just up one side of 113 00:04:34,980 --> 00:04:33,460 this and then we'll get two flares the 114 00:04:37,080 --> 00:04:34,990 main result is that these stars are 115 00:04:38,400 --> 00:04:37,090 actually all kind of similar at least in 116 00:04:41,159 --> 00:04:38,410 astronomy terms which means you know 117 00:04:43,110 --> 00:04:41,169 order of magnitude as far as how much 118 00:04:44,749 --> 00:04:43,120 what fraction of light they emit in 119 00:04:47,999 --> 00:04:44,759 their photo chemically active 120 00:04:49,950 --> 00:04:48,009 ultraviolet part of the spectrum same is 121 00:04:51,540 --> 00:04:49,960 true for the extreme UV but they all are 122 00:04:53,129 --> 00:04:51,550 somewhat elevated relative to the Sun 123 00:04:54,570 --> 00:04:53,139 the cool thing about this is it means 124 00:04:56,930 --> 00:04:54,580 that once the Hubble Space Telescope 125 00:05:01,379 --> 00:04:56,940 dies and we can't get ultraviolet on 126 00:05:03,089 --> 00:05:01,389 servations anymore you if you want to do 127 00:05:06,810 --> 00:05:03,099 photochemical modeling you can sort of 128 00:05:08,040 --> 00:05:06,820 just pick a good median star in here and 129 00:05:09,839 --> 00:05:08,050 you'll at least know it to within an 130 00:05:13,770 --> 00:05:09,849 order of magnitude you're kind of on 131 00:05:15,120 --> 00:05:13,780 money all right so the cool thing about 132 00:05:17,520 --> 00:05:15,130 these observations is we can look at 133 00:05:21,779 --> 00:05:17,530 them both spectrally but also Tim poorly 134 00:05:24,689 --> 00:05:21,789 we can split them up in time and so for 135 00:05:28,620 --> 00:05:24,699 this next part I talk I am just focusing 136 00:05:29,909 --> 00:05:28,630 on the UV purely and these are the only 137 00:05:32,070 --> 00:05:29,919 observations for which we have several 138 00:05:34,680 --> 00:05:32,080 hours of data and for which we can 139 00:05:36,750 --> 00:05:34,690 actually buy things up in time so when 140 00:05:40,020 --> 00:05:36,760 you start cutting that up in time what 141 00:05:42,420 --> 00:05:40,030 you see is that all right let's get this 142 00:05:45,379 --> 00:05:42,430 real fast not super necessary you see 143 00:05:48,360 --> 00:05:45,389 that the ultraviolet emission which is 144 00:05:54,689 --> 00:05:48,370 mostly manifested in a few very narrow 145 00:05:57,120 --> 00:05:54,699 emission lines it often flares it took 146 00:06:00,480 --> 00:05:57,130 quite an extreme extent so for example a 147 00:06:01,980 --> 00:06:00,490 mission from this one mission line went 148 00:06:03,810 --> 00:06:01,990 to a hundred times of its quiescent 149 00:06:06,060 --> 00:06:03,820 level during this flare and we saw this 150 00:06:08,670 --> 00:06:06,070 on five out of seven of the M stars that 151 00:06:11,210 --> 00:06:08,680 were in the survey so it's common even 152 00:06:14,370 --> 00:06:11,220 though these M stars are basically 153 00:06:16,290 --> 00:06:14,380 normal or typical I guess you would say 154 00:06:19,529 --> 00:06:16,300 they don't stand out from stellar 155 00:06:21,300 --> 00:06:19,539 populations in any particular way oh so 156 00:06:23,129 --> 00:06:21,310 flares are a big deal in these stars 157 00:06:24,210 --> 00:06:23,139 they're happening frequently enough that 158 00:06:29,100 --> 00:06:24,220 even with three and a half hours of 159 00:06:31,020 --> 00:06:29,110 observations you can you can see one so 160 00:06:33,690 --> 00:06:31,030 then I can look at these Flyers 161 00:06:35,550 --> 00:06:33,700 statistically make a cumulative 162 00:06:38,250 --> 00:06:35,560 distribution plots like this where you 163 00:06:39,900 --> 00:06:38,260 have how frequently the players occur 164 00:06:42,380 --> 00:06:39,910 if they have an energy less than or 165 00:06:44,820 --> 00:06:42,390 equal to the value on the x axis and 166 00:06:46,230 --> 00:06:44,830 this is similar to like creator 167 00:06:48,200 --> 00:06:46,240 accounting diagrams or I think something 168 00:06:52,110 --> 00:06:48,210 in biology would be a like a lifetime 169 00:06:54,960 --> 00:06:52,120 plot so the stars in our muscle sample 170 00:06:57,390 --> 00:06:54,970 fall right here sort of in between the 171 00:07:00,630 --> 00:06:57,400 Sun down here on the bottom and some 172 00:07:02,160 --> 00:07:00,640 stars that have had have been the 173 00:07:04,080 --> 00:07:02,170 subject of a lot of observations because 174 00:07:09,180 --> 00:07:04,090 they flare a lot so we knew that they 175 00:07:12,300 --> 00:07:09,190 were pretty interesting so again boy I 176 00:07:14,490 --> 00:07:12,310 was significant and last night I decided 177 00:07:17,010 --> 00:07:14,500 I would integrate this and see just how 178 00:07:19,740 --> 00:07:17,020 much energy a planet might receive from 179 00:07:22,110 --> 00:07:19,750 these UV flares and the answer was a 180 00:07:24,900 --> 00:07:22,120 little surprising it was enough to 181 00:07:27,270 --> 00:07:24,910 obliterate quite a few Earth's which you 182 00:07:28,710 --> 00:07:27,280 know I guess NASA should have consulted 183 00:07:30,210 --> 00:07:28,720 me before they said Kepler up there and 184 00:07:31,440 --> 00:07:30,220 waste all that money I could have told 185 00:07:35,340 --> 00:07:31,450 him that then we're going to find 186 00:07:37,140 --> 00:07:35,350 anything but uh but I think the real 187 00:07:39,210 --> 00:07:37,150 problem here is that I don't know what's 188 00:07:43,020 --> 00:07:39,220 a good upper limit for the integration 189 00:07:44,430 --> 00:07:43,030 and what I used was you know what's the 190 00:07:46,800 --> 00:07:44,440 highest energy where you get one flare 191 00:07:49,260 --> 00:07:46,810 in the life of the universe and I 192 00:07:51,000 --> 00:07:49,270 imagine that the real upper limit is 193 00:07:54,420 --> 00:07:51,010 much lower but that's something I'm 194 00:07:56,370 --> 00:07:54,430 going to be exploring in the future okay 195 00:07:58,320 --> 00:07:56,380 so what do these players mean four 196 00:08:00,600 --> 00:07:58,330 atmospheres well here I'm just going 197 00:08:04,050 --> 00:08:00,610 into the literature to give you all some 198 00:08:06,210 --> 00:08:04,060 perspective there was a group that 199 00:08:07,860 --> 00:08:06,220 published a paper in astro bio in 2010 200 00:08:09,480 --> 00:08:07,870 where they exposed an earth atmosphere 201 00:08:12,150 --> 00:08:09,490 to the largest player that's ever been 202 00:08:14,750 --> 00:08:12,160 observed on an in star and if they 203 00:08:18,510 --> 00:08:14,760 incorporate just the UV light they get 204 00:08:21,870 --> 00:08:18,520 somewhat modest depletions of ozone 205 00:08:23,580 --> 00:08:21,880 factory for you for ozone and a few 206 00:08:26,190 --> 00:08:23,590 orders of magnitude for or one order of 207 00:08:27,480 --> 00:08:26,200 magnitude for water but there's not much 208 00:08:29,850 --> 00:08:27,490 water up at the levels where they saw 209 00:08:34,350 --> 00:08:29,860 that so here you're looking at basically 210 00:08:36,860 --> 00:08:34,360 amount versus altitude but then they 211 00:08:41,850 --> 00:08:36,870 decided they would incorporate particles 212 00:08:43,260 --> 00:08:41,860 which as you might know for the Sun 213 00:08:45,270 --> 00:08:43,270 often players are associated with 214 00:08:47,640 --> 00:08:45,280 ejections of particles which do things 215 00:08:49,080 --> 00:08:47,650 like mess with our power grids and when 216 00:08:51,430 --> 00:08:49,090 they did that they got pretty 217 00:08:55,460 --> 00:08:51,440 substantial depletions of ozone 218 00:08:57,850 --> 00:08:55,470 it like you know almost goes away in the 219 00:09:00,019 --> 00:08:57,860 upper atmosphere the result is a 220 00:09:02,680 --> 00:09:00,029 reduction of the ozone column do I think 221 00:09:04,670 --> 00:09:02,690 about Timbers in its original value and 222 00:09:05,840 --> 00:09:04,680 so that's pretty significant it might 223 00:09:07,460 --> 00:09:05,850 sound like that might be damaging for 224 00:09:09,050 --> 00:09:07,470 life but Tim person that Bo zone is 225 00:09:10,910 --> 00:09:09,060 still okay and then there was this 226 00:09:12,740 --> 00:09:10,920 really interesting paper recently by the 227 00:09:15,019 --> 00:09:12,750 air patient group where they suggested 228 00:09:17,650 --> 00:09:15,029 that if you expose the earlier at the 229 00:09:19,880 --> 00:09:17,660 atmosphere to players like these then 230 00:09:22,940 --> 00:09:19,890 you might actually produce some 231 00:09:24,920 --> 00:09:22,950 biologically relevant molecules and in 232 00:09:26,060 --> 00:09:24,930 fact these are also greenhouse gases so 233 00:09:30,500 --> 00:09:26,070 they could help solve the faint young 234 00:09:33,800 --> 00:09:30,510 Sun paradox so basically flares are 235 00:09:36,079 --> 00:09:33,810 important but there's one caveat one 236 00:09:37,970 --> 00:09:36,089 important thing that this brings to mind 237 00:09:39,940 --> 00:09:37,980 I hope you all can read this in the back 238 00:09:42,110 --> 00:09:39,950 but a question that we need to answer is 239 00:09:43,550 --> 00:09:42,120 just how many particles are actually 240 00:09:45,110 --> 00:09:43,560 coming out of these indoor flares if 241 00:09:47,329 --> 00:09:45,120 import players are so frequent and 242 00:09:49,519 --> 00:09:47,339 strong and they we have pretty good 243 00:09:50,900 --> 00:09:49,529 reason to believe that it might be 244 00:09:53,200 --> 00:09:50,910 different than the Sun we might not just 245 00:09:55,430 --> 00:09:53,210 be able to scale the Sun in this case 246 00:09:57,560 --> 00:09:55,440 but until we have measurements we don't 247 00:10:00,680 --> 00:09:57,570 really know and so far we don't have any 248 00:10:09,050 --> 00:10:00,690 measurements so with that I'll leave the 249 00:10:10,660 --> 00:10:09,060 conclusions and take any questions I'm 250 00:10:14,420 --> 00:10:10,670 gonna ask the first question this time 251 00:10:15,950 --> 00:10:14,430 so you said that you got a five out of 252 00:10:17,210 --> 00:10:15,960 seven of these had these flares while 253 00:10:18,980 --> 00:10:17,220 you're observing it over three and a 254 00:10:20,690 --> 00:10:18,990 half hours yeah can you back out an 255 00:10:23,900 --> 00:10:20,700 expected actual frequency of the flares 256 00:10:25,400 --> 00:10:23,910 how often on average Oh Clara I mean is 257 00:10:28,310 --> 00:10:25,410 it is it once every three and a half 258 00:10:30,890 --> 00:10:28,320 hours is it uh yeah it's about that's 259 00:10:32,540 --> 00:10:30,900 well yeah if you divided by the seven 260 00:10:35,150 --> 00:10:32,550 stars you get about one every three and 261 00:10:37,100 --> 00:10:35,160 a half hours so and these are players 262 00:10:39,530 --> 00:10:37,110 that so the one I showed you of course I 263 00:10:42,050 --> 00:10:39,540 showed you the best one that was 100 264 00:10:44,390 --> 00:10:42,060 times you know at an elevation of 100 265 00:10:47,269 --> 00:10:44,400 times the quiescent level but the other 266 00:10:56,449 --> 00:10:47,279 ones are about 10 times minimum so 267 00:11:03,359 --> 00:11:00,569 so I'm great talk are these flares that 268 00:11:04,710 --> 00:11:03,369 are coming out directional and if so 269 00:11:07,589 --> 00:11:04,720 what's the probability that they would 270 00:11:08,789 --> 00:11:07,599 actually be hitting the planet yeah this 271 00:11:14,369 --> 00:11:08,799 is something I haven't explored fully 272 00:11:15,839 --> 00:11:14,379 either and I am sure that the of course 273 00:11:18,119 --> 00:11:15,849 you have to be at least on the right 274 00:11:19,379 --> 00:11:18,129 hemisphere of the star the players are 275 00:11:22,979 --> 00:11:19,389 so short that the star is not going to 276 00:11:24,659 --> 00:11:22,989 rotate into the view of the planet dirt 277 00:11:26,729 --> 00:11:24,669 over the course of a player for at least 278 00:11:31,019 --> 00:11:26,739 the players that we saw so direction 279 00:11:34,559 --> 00:11:31,029 matters and but I don't have any good 280 00:11:43,670 --> 00:11:34,569 answer for like how how directed it 281 00:11:51,720 --> 00:11:49,680 so you you said that to measure the 282 00:11:55,440 --> 00:11:51,730 particle flux you can't just scale down 283 00:11:57,420 --> 00:11:55,450 the Sun so is there any plan to study m 284 00:11:59,639 --> 00:11:57,430 dwarfs in the near future to like try 285 00:12:02,009 --> 00:11:59,649 and back out what their particle flux is 286 00:12:03,449 --> 00:12:02,019 compared to like what we do with our son 287 00:12:06,480 --> 00:12:03,459 and then comparing it to other sun-like 288 00:12:09,449 --> 00:12:06,490 stars yeah the most intriguing plan that 289 00:12:10,560 --> 00:12:09,459 I've heard is I know and hopefully I 290 00:12:12,090 --> 00:12:10,570 won't murder this because I don't know 291 00:12:13,740 --> 00:12:12,100 much about this particular type of 292 00:12:15,210 --> 00:12:13,750 observing but I know there's a group 293 00:12:16,740 --> 00:12:15,220 that it's empty to get radio 294 00:12:18,360 --> 00:12:16,750 observations where you could see a 295 00:12:20,579 --> 00:12:18,370 mission from the particles as they 296 00:12:23,610 --> 00:12:20,589 spiral out on the magnetic field lines 297 00:12:25,710 --> 00:12:23,620 from the star and that would be an 298 00:12:27,900 --> 00:12:25,720 awesome basically direct measurement of