The planet has the less than romantic name TOI 700 d, but its discovery has generated passion among those searching for another Earth, including Emily Gilbert. The graduate student is lead author of a paper about the new world. TESS, the Transiting Exoplanet Survey Satellite, played a key role in its discovery. MIT planetary scientist and astrophysicist Sara Seager returns to tell us about this powerful tool and more. We also visit with the leader of NASA heliophysics research as she awaits launch of the Solar Orbiter. Look out! The rubber asteroids are back on Whats Up!

A Planetary Society r-r-r-r-rubber asteroid AND a Planetary Radio t-shirt from the Planetary Society store.

The Spitzer Space Telescope was named after astrophysicist Lyman Spitzer, Jr. What was his middle name?

The winner will be revealed next week.

Of the planets and current dwarf planets in our solar system, which has the shortest (solar) day?

Haumea is covered in crystalline ice,Like that from your fridge that is cooling and nice.It rotates in less than four hours or so,The shortest of all solar days that we know.It orbits the sun from a long ways away,And takes about six thirty four thousand days!

Matt Kaplan: [00:00:00] Another Goldilocks World and the powerful Space Camp that helped us discover it, this week on Planetary Radio.

Welcome. I'm Matt Kaplan at the Planetary Society with more of a human adventure across our solar system and beyond. We've got so much for you this week, planetary scientist and astrophysicist, Sara Seager, is back to tell us about TESS, the space telescope that is revealing new exoplanets. One of those worlds is in the fabled habitable zone of its Dwarf star. We'll learn about it from Emily Gilbert, the graduate student who served as lead author of one of three papers about TOI 700 d. We'll also hear about the beginning of a mission to learn more about our own star, and out there beyond it all, waits Bruce Betts with this week's what's up, including the return of the rare and [00:01:00] dangerous rubber asteroids. Sounds like a lot, but there's so much more going on in space exploration. Here are a few headlines from the most recent edition of the down Lake collected by Planetary Society, editorial director, Jason Davis.

Welcome home. NASA astronaut, Christina Koch is back on Terra Firma after 328 days in low earth orbit. She now holds the record among women for the longest single space flight, and she says she looks forward to someone else breaking that record. NASA's Mars 2020 Rover has been packed up and shipped off to the Kennedy Space Center. The launch window opens in July and runs into August. And the Russian Space Agency, Roscosmos reports that all 13 science instruments have been installed on the Lander that will carry the European Space Agencies, Rosalind Franklin Rover to the Martian surface. Same launch window as the NASA mission, of course. You'll find these [00:02:00] stories and more at planetary.org/down link, and soon you'll find much more including great space images, cool facts and announcements from the Planetary Society and it will all be delivered to your inbox. Stay tuned.

The sun is about to gain a new satellite. The Solar Orbiter Mission was launched from Cape Canaveral on the evening of, how appropriate, Sunday, February 9th. The joint ESA, NASA mission will eventually go into a more or less polar orbit around our star revealing those poles with cameras for the first time. Former Planetary Radio associate producer, MaryLiz Bender now with Cosmic Perspective was there to watch the Atlas five lift off. Here's a report she shared with us just two days before this launch.

MaryLiz Bender: I just got back from Kennedy Space Center after the Prelaunch NASA Science Briefing for the Solar Orbiter mission. There, I found a room of very excited scientists. Among them [00:03:00] was one of my favorite people to talk to, Nicky Fox. She is the director of the division of Heliophysics at NASA. Nicky has worked closely with a Solar Orbiter team and she was also the project scientist of the Parker Solar Probe Mission. We last talked just after the Parker Solar Probe launch in August of 2018, and now I am so glad to have had the chance to talk to her again just a couple of days before the launch of its sister mission, Solar Orbiter.

Nicky Fox: I was extremely excited the last time we talked cause I just watched the Delta IV Heavy lift off the pad and I was in a very exc- I think you actually introduced me as a very excited Nicky Fox, and I was indeed. Uh, I was over the sun with excitement with the Parker Solar Probe launch and equally as excited now to see Solar Orbiter go on Sunday.

MaryLiz Bender: You remember? That's amazing. That sparks my memory. You said, "I'm over the moon, I'm over the sun." [laughs].

Nicky Fox: That's true. I... and I was.

MaryLiz Bender: [laughs].

Nicky Fox: I describe myself as a launch junkie. Um, I... this is [00:04:00] the most exciting thing for me. Um, I think I got the bug, uh, very early. I worked on the, the Van Allen Probes and I, I was very blessed to work with the team very closely and, uh, see all that last minute preparation. Uh, obviously with Parker, I was down here for the last six weeks working with the team and so I know what they're going through, so even though I haven't had the opportunity to, to be in the clean room with Solar Orbiter, I know the excitement that this team is feeling. And so yes, uh, we cannot wait to see that, that rocket lift off the pad.

MaryLiz Bender: Yes. I say this all the time. So, I'm a launch junkie and I don't have any intimate connection really with this thing except to feel like humanity's doing this amazing thing together. Right? But I always say that watching a night launch is like watching a sun rise in the middle of the night.

Nicky Fox: I- it really is. And, and you know, you see the spectacle of it, then you, you hear, and then you feel the pressure, and there is, you know, that. Yes, it's wonderful. Um, daytime launch is a really nice... I don't wanna knock our daytime launches, but man, [00:05:00] the sight of that thing going at... uh, during the night is just amazing.

MaryLiz Bender: Can you tell me about your involvement with this particular mission? I know you answered a lot of questions today about Parker Solar Probe, really great data coming back from that right now, but what has been your role, um, in the Heliophysics Division for Solar Orbiter?

Nicky Fox: Well, so I started working with Solar Orbiter a number of years ago when I was still uh, the Parker Solar Probe project scientist, and I worked very, very closely with Daniel Mu- Mueller, um, and we, we really wanted to collaborate and we wanted to, to, to get these missions working together because they are so much better as a team. And so I've had a long involvement with the Solar Orbiter team, but since I moved down to NASA Headquarters, I'm sort of in charge of making sure that everything is perfect for launch on Sunday. And so I've worked extremely closely with our counterparts at ESA, uh, with, with our folks here at NASA's Launch Service Program with ULA, and just making sure everything is ready to go.

NASA has a couple of instruments that are, are flying on Solar Orbiter and... but it's, it's more than just those instruments. [00:06:00] It's really that, that team of 10 instruments working together, and so, uh, the team here, um, all of the different, the stakeholders, all of the partners just all pulling in the same direction for launch on Sunday.

MaryLiz Bender: I really loved the vibe of the excitement over the international collaboration on the science, especially, how do those decisions get made? Or how do you all talk to one another and say, "Hey, we've got something over here we think you'd like to work on?" Or, you know, how, how do people raise their hand to work with NASA and ESA?

Nicky Fox: It's pretty much like that. We work very, very closely with all of our partner agencies and we, you know, we, we meet together and we say, "Hey, there's this opportunity, would you like to take part in it?" Um, so there are lots of collaborations with Heliophysics, the sort of notable ones, the Ulysses and SOHO, uh, now of course, uh, Solar Orbiter adding to that legacy. And so, yeah, i- it really is just a, "Hey, there's an opportunity. Would you like to join us?" And we're always looking for ways to, to work together, uh, to really do things better. That's exactly how it happens for Heliophysics. [00:07:00] The thing I love about it is, honestly, wherever you go in the Solar System, we wanna go with you. We will take data from anywhere. We work really closely with our planetary colleagues, um, and now with our astrophysics colleagues as to, "Hey, what is the information we're learning about ASTA, how can we help you apply that to other stars?" And so, you know, I just love science.

MaryLiz Bender: Hmm.

Nicky Fox: Um, the sun has been... it's, you know, it guides us, it's there every day. We are sometimes argue about, which was the first branch of science. I always say it's Heliophysics because everybody looked up at the sun and stared at it and wondered what it was. And so we are now sending missions up close to really explain what's happening at our star.

MaryLiz Bender: It emits the source of life, right? I mean, so essentially you are studying almost every branch of science when you study the sun.

Nicky Fox: Absolutely. Yes. We put years and years into these missions. Daniel said he's working on this missions for 13 years. Parker Solar Probe, I'd worked on it for eight when it launched. You know, I mean there's... you've, you put a lot of work into it and it's not like we have another mission just sitting there that if something goes wrong [00:08:00] here we can launch it, this is our one shot at doing this. And so, yes, we're all nervous, but it's really just pure excitement. We can't wait to see Solar Orbiter join Parker Solar Probe, their sister, sister missions. We've always thought of them like that and we can't wait for them to get up there and start working together. But, as always, it's a great time to be a hyliophysicist.

Matt Kaplan: Cosmic Perspective's Mary Liz bender talking with NASA's Nicky Fox just two days before the beginning of the Solar Orbiter Mission.

The legacy of the Kepler Mission lives on. as of mid January, more than 4,000 exoplanets have been confirmed, and most of these were discovered by that space telescope. There are thousands more waiting for confirmation and now the list of worlds is growing, thanks to Kepler's daughter TESS. We'll focus in a few minutes on just one of these, a roughly earth sized planet known as TOI 700 d that orbits in its stars habitable zone. But first for [00:09:00] an overview of TESS and the current state of exoplanet research. I called on professor Sara Seager. She is an astrophysicist and planetary scientist at MIT where her team teases evidence of exoplanets from the data returned by TESS. Sara, welcome back to Planetary Radio. Uh, it's been a while since we've talked. In fact, well, we may mention those previous appearances because they'll be pretty relevant to today's discussion, but it's great to have you back on the show.

Sara Seager: Thanks, Matt. Great to be back.

Matt Kaplan: Let's talk about the transiting exoplanet survey satellite before we get onto other things. As I mentioned to you a moment ago, we have not talked about in depth on this show with... it's come up because it's done some great work, but we haven't brought it up in depth since the launch, which now was nearly two years ago. Has TESS been meeting everybody's expectations?

Sara Seager: Absolutely. Tess has, I would say even been exceeding expectations.

Matt Kaplan: That's great.

Sara Seager: Yeah. [laughs].

Matt Kaplan: I [00:10:00] see a... saw in looking at the website that it was going to cover the sky, what, 200,000 stars in two years, but, but we're not talking about it ending its mission in, in April, which would be the second year anniversary, are we?

Sara Seager: No, not at all. In fact, TESS has been extended. It has passed a review at NASA to get an extended mission, so it will be going for another two or three years, and honestly TESS could go on indefinitely. It's orbit is incredibly stable and it doesn't need much fuel. It really doesn't need much at all to keep going.

Matt Kaplan: Is that especially good news? Because, I mean it... the longer you stare at these stars and the planets that pass in front of them, the better off you are.

Sara Seager: That's right. It's better to stare at an object longer because the more transits we see, the more planets we can find. Right now, TESS is mostly finding planets that have periods, their year, the time it takes to go around their star is less than about a month, so it would be way better if we could stare at the same stars, you know, over and over again and find much longer [00:11:00] period planets. Also, if we can stare more often, we can bing the data down and we can look for smaller and smaller planets. Finally TESS's prime mission covers about 70% of the sky. During the extended mission, TESS has a chance to fill in the rest of the sky.

Matt Kaplan: That's great. Did we learn the basics of this through Kepler and the great work that that, uh, immediate ancestor of TESS did?

Sara Seager: We did. Kepler was so incredibly pioneering. It will be a legacy for all time. A lot of what we do on TESS builds directly on, on Kepler. The data reduction techniques we use, the data pipelines even, and all of our strategies and methods.

Matt Kaplan: So out of this 200,000 stars in this initial period of operation by TESS, how many roughly earth sized worlds in their habitable zones, uh, do... can we expect to find out of, out of this data?

Sara Seager: It's true TESS is looking at [00:12:00] 200,000 stars at two minute cadence in the prime mission, but did you know that TESS is also looking at millions more stars? Millions.

Matt Kaplan: No.

Sara Seager: It is.

Matt Kaplan: Wow.

Sara Seager: Because the team found a very clever way to be able to down link what we call full frame images. You know, it's so hard to send data back to earth, it's very huge bottleneck and so we can't send all the stars in the field of view, but we're able to in the data onboard, to stack the data and send 30 minute cadence down to the ground. And so in addition to studying those 200,000 special- specially chosen stars, we can also look at so many more stars.

Matt Kaplan: That's fantastic. All right, well the more you look at, the more of these, I hesitate to use the phrase, but I will, earth like planets we're going to find, right?

Sara Seager: You do hesitate for good reason because-

Matt Kaplan: [laughs].

Sara Seager: ... we really want to reserve Earth-like for the true earth twin, the earth size, earth mass planet orbiting a sunlight star in a one year period. TESS, it turns out is purposely designed to be very, [00:13:00] very sensitive to small planets orbiting very small stars. They're very different from our sun, M dwarf stars among the most common types of stars that we have.

Matt Kaplan: So MIT, one of many institutions, but the, the lead institution in many ways for dealing with, uh, TESS data, I mean, what's it like there? Is it. is it a busy place, is... a you and your colleagues search for these worlds?

Sara Seager: It's very busy, very busy and it's actually mostly young people getting, getting the hard work done. Here at MIT, we're responsible for finding the planet candidates that go out to the community so people can work on them. Here we actually brand objects, TESS objects of interest. So whenever you say TOI this, TOI that, it actually came from my team's work here. The computers do all the hard work, there's the official data pipeline out at NASA Ames that works on the 20,000 objects per month at two minute cadence, and here at MIT, we run our so-called quick look pipeline on hundreds of thousands of stars that come at 30 minute cadence [00:14:00] and the computers churn away and they present us with a long list of what they call threshold crossing events. And it's our job here using more computer programs to find out which ones are worthy of being designated a TESS object of interest. And at the very end of that process, it's gonna sound funny to you, but we actually have humans, we call it [inaudible 00:14:19].

Matt Kaplan: [laughs].

Sara Seager: Yeah. We have [inaudible 00:14:20], groups and we meet every few say from one to three o'clock and it's like a rotating group of trained experts, and we literally look through the data, and there's data products that come with it and we try to decide whether it's worth putting it out to the community and giving it an official TOI stamp so people can look at it further.

Matt Kaplan: That is so cool. I have to think that over the years that we have been finding exoplanets, you and other folks like your team there at MIT have gotten better and better at this?

Sara Seager: Definitely, you can say that finding planets by transits is actually a very mature method. It is standard operating procedure.

Matt Kaplan: Your [00:15:00] Seager equation, uh, a twist on the famous Drake equation, you, you really consider with this only these habitable zone and sized planets, right? I... and, and I, I noted that one of your factors in the equation... by the way, we'll put up a link to this somewhere online, maybe through your own website, one of the factors calls for stars that are quiet and, and that's gonna come up again when we talk to, um, Emily Gilbert in a minute but, but tell us why that was an important factor to include.

Sara Seager: At the moment, we are struggling to find planets around variable star... very highly variable stars. It turns out that stars, even our own sun because of its spots, vary with time. Uh, many of these [inaudible 00:15:45], stars, they're just so variable. It's like, "Wow, what happened?" And the star is not just constant with time. Every time TESS takes an image of it, it's brightness is slightly different and this is usually due to spot, spottedness of the star and its stars are rotating so [00:16:00] different spots are forming and are coming in and out of view. It's sort of a just a selection effect. It's a problem with nature that the noisy stars are hard for us to find planets around and they'll also be hard for us to study planets around later.

Matt Kaplan: So this isn't a reference to, uh, low activity by the star in terms of like solar flares, which you know I think is one of the things we, we will talk with Emily Gilbert about because that dwarf star around which TOI 700 d is revolving uh, is a, is a fairly quiet star, but, but that is another issue, right?

Sara Seager: Right. These spotted stars, we think, correlate with stars with flares-

Matt Kaplan: Mm-hmm [affirmative].

Sara Seager: ... so they're just generally active all around and these flares are something else. I mean, apparently Proxima Centauri, our very nearest star to our earth, to our solar system, which has a planet around it, apparently that flare, that if you were looking at it at the right time from a truly dark sky, you would have seen it brighten.

Matt Kaplan: Oh my, that's bad news. [laughs].

Sara Seager: I know. Right. [00:17:00] I don't know, we're really not sure. Maybe, maybe there's intelligent beings on planets orbiting stars that flare, and they're looking at our sun and their version of the Drake equation says, noisy star. Maybe they're thinking, "Now there's no way those folks can get energy. How do they recharge their power grid?" [laughs].

Matt Kaplan: [laughs].

Sara Seager: We really don't know.

Matt Kaplan: Yeah, we don't know what we don't know, in fact. With that in mind, you came on in 2017 because you were part of the announcement of the discovery of those worlds around the star known as TRAPPIS 1, three years later, are we much closer to, to finding a planet that has signs of possible life?

Sara Seager: Yes and no. That's the scientist answer always.

Matt Kaplan: Yeah.

Sara Seager: We're no closer in terms of having data in our hands. I don't have a spectrum that I can analyze and give you a yes or no on that. We're still closer because more methods have developed, more [00:18:00] candidate bio sinker gases have been thought of, and the James Webb is closer to launch, so we're definitely closer in that sense, but no, we can't... we don't have anything solid to report on at the moment.

Matt Kaplan: I'm glad you mentioned the James Webb. The JWST, James Webb Space Telescope, of course. The first time you came on the show, we met each other at Northrop Grumman right next to where that great infrared telescope was coming together, but that was more than five years ago. It sounds like you're still very much looking forward to this, uh, powerful new tools starting to do its work.

Sara Seager: Not just me, but our entire exoplanet community's waiting, literally waiting and excitedly expectantly wanting James Webb to be launched and be taking data. You would not believe how many people are in this field right now, even as compared to 2017.

Matt Kaplan: I know, sadly we've got this, this little, uh, interruption of at least some, uh, infrared data because I mean we were just talking about it [00:19:00] last week on this show, we've lost the Spitzer Space Telescope, that other infrared, uh, instrument that has been doing such great work out there in space. What does that mean for, for you and, and for the exoplanet community?

Sara Seager: Spitzer was a workhorse for exoplanets. I would wish we could look at the glass as half full in this case because Spitzer was supposed to stop operating, I wanna say five to 10 years ago. It's incredible how the scientists and engineers were able to keep Spitzer working and it's been so great, recently, mostly for validating exoplanets, by looking for them from space or by trying to characterize them by their secondary clips or by what we call their thermal phase curves. Uh, it's definitely sad to see Spitzer wrap up.

Matt Kaplan: Hmm. All right. Well, like we said, if everything goes well and NASA's still hoping that this happens next year or 2021, we'll have the JWST out there. Do you have some confidence that with this powerful new tool that you will start to get [00:20:00] those spectra from these planets that, that might tell you, "Hey, look, there's some oxygen or, or some other sign that could be an indication of life?"

Sara Seager: Well, yes and no, I know, yes and no. [laughs].

Matt Kaplan: [laughs]. Once again?

Sara Seager: I'll, I'll say that everyone, including myself, is working as hard as possible to make sure that, you know, in the limited lifetime of the James Webb Space Telescope, that we're able to get all the data we need. It's a bit tricky because we don't have any earth like planets that the James Webb can observe. It doesn't have the capability, nor do we have any that we will be able to work with and understand in detail. We're kind of going blind in a way because all these planets around M dwarf stars, they're very different from earth and we really, um, we're working hard to expect the unexpected and to plan for what might be out there. So we're trying to make sure that as a community we cover all the right planets, at the right wavelengths, and that we just have that great data to work with. So we're hopeful that we'll find it, but, you know, life has to be there.

Matt Kaplan: Yeah.

Sara Seager: We have to [00:21:00] keep the right planets. Life has to be generating gases that accumulate in the atmosphere.

Matt Kaplan: You know, the debate goes on as to what data telescopes may be able to return, spectra, that would actually say to us, "Yeah, this could be life," as opposed to some non biological process. Do you see progress in that area as well?

Sara Seager: Yes, there's been a lot of progress, somewhat to the negative in a way, because oxygen is our favorite bio signature gas, uh, here on earth. Our atmosphere is filled with oxygen to the 20% by volume. But without life, without plants and photosynthetic bacteria, we'd have no oxygen. And in the last few years since we've talked, people have been working hard to come up with false positive scenarios. What if you found oxygen and it wasn't related to life. So people are working on scenarios with corroborating gases in the atmosphere. And it's funny because someone comes up with a new scenario where oxygen could be a [00:22:00] false positive, and then a couple of years later, someone shoots that scenario down.

Matt Kaplan: [laughs].

Sara Seager: So we're making progress here. I think we'll be, I think we'll be ready.

Matt Kaplan: But it's good science, right? I mean, you want people to be shooting those down?

Sara Seager: We want people to be shooting those down, we want to know what we need, what information we need. It's tough, though. I liken it to a forensic crime scene. You're gonna have clue, you're gonna have evidence, but you've got to put the story together.

Matt Kaplan: Wow. Yeah, it is a detective story, isn't it? Before we go, as I said, we're gonna be talking to Emily Gilbert at the University of Chicago uh, in just a moment or two. And, of course, she is just a grad student and yet she was the lead author of one of these three papers that, that you are also a co-author of, uh, do you see this as, as something very positive that we're seeing, uh, grad students and sometimes even undergraduates, uh, popping up as people who are doing, making great contributions to, uh, our knowledge in planetary science?

Sara Seager: Yes, TESS is a wonderful dataset [00:23:00] and there's so many planets, so many stars. It's just fantastic to see so many young people like Emily Gilbert really jumping on the data, and it's great to see them be able to find and work on such amazing new planets.

Matt Kaplan: Sara, I, I sure look forward to that, uh, launch and Firstlight from, uh, the James Webb Space Telescope and I don't think I will wanna wait longer than that to, uh, have another conversation with you. Maybe it'll happen before that, but uh, can I get you back on the show when, uh, when that big thing unfolds, fingers crossed, out there in space?

Sara Seager: Absolutely.

Matt Kaplan: Thank you, Sara. Great to talk to you.

Sara Seager: Thanks, Matt.

Matt Kaplan: That's Sara Seager, professor of planetary science and physics at MIT and a MacArthur fellow among her other honors. She is, uh, waiting for more data which is arriving, but uh, we'll see far more of it when the James Webb Space Telescope begins to do its work.

We're far from finished with this week show. Just pausing for a minute to remind you that there's much more [00:24:00] out there across the expanse for us to discover, which is a not too subtle way to tell you that we are once again brought to you by Amazon Prime Videos, the Expanse, Season Four. I just had a listener asked me if she should start by reading the books or just diving to the TV series. I love the books and highly recommend them, but the show is so very good and so true to the books where it matters that I'm just fine with anyone who wants to start with Amazon Prime Video and I remain indebted to Jeff Bezos for rescuing the show when it was dropped by sci-fi.

To review, season four finds the crew of the Rocinante exploring worlds beyond the wormhole like Ring Gate. Actually one world in particular that offers riches to any settlers from earth, Mars, or the belt who can reach it and survive. That survival is made far less likely by the magnificent ruins of a long dead alien civilization. Great [00:25:00] characters, spectacular action and vistas and human nature at its best and worst. That's the Expanse with episodes streaming now on Amazon Prime Video.

We've learned about TESS and related efforts from Sara Seager, let's go now to the University of Chicago to learn about just one newly discovered world. Three papers about it were published just a month ago and the first of these featured our next guest as its lead author. Emily Gilbert is a graduate student working toward her PhD. Emily, thanks very much for joining us on Planetary Radio and congratulations on the publication of this paper about this uh, new world, which, who knows, may not be so different from our own. Uh, again, thanks for joining us.

Emily Gilbert: Thanks so much, I'm so excited to be chatting with you.

Matt Kaplan: Tell us a little bit about TOI 700 d. I, I hope that someday it'll get a, a, a more romantic name than that, but I guess that'll, that'll do for now. [00:26:00] We just last week in our tribute to the Spitzer Space Telescope, we were talking about the TRAPPIST 1 worlds, now this one, your paper and the two others about it only just uh, were published at the beginning of January, toward the beginning of January. There still aren't that many of these worlds that are in the so called habitable or our Goldilocks zones, are there?

Emily Gilbert: No, I think we have somewhere around a dozen planets that are roughly earth sized and in the habitable zone.

Matt Kaplan: I guess this would be the latest edition?

Read the rest here:

Another Goldilocks World and the Space Telescope That Discovered It - The Planetary Society