Women in Exoplanets: Meet Natalie Batalha

Natalie Batalha began work on the Kepler mission as a postdoc and now serves as the Deputy Science Team Director.  She has a fascinating story, and I’m delighted that she has agreed to be featured here on our site this week.  Natalie and I sat down during a break at the American Astronomical Society meeting in January; excerpts from our interview follow.

Natalie, how did you get started in this field?

I was at the Florence conference when the very first announcement of an extrasolar planet was announced [in 1995].  That very first announcement was extremely exciting.  But it didn’t really sink in.  It took time for it to sink in.  Meanwhile, I finished my thesis.  I was working on activity in young, late type stars, — stars like our sun, but more in their infancy, maybe teenage suns.  In reading about the various techniques to detect planets, I stumbled upon a report by Bill Borucki and the Kepler–well, it wasn’t Kepler at that time, it was FRESIP– science team.  The report was in the office of Gibor Basri, who was a long-time collaborator.  I worked for Gibor as an undergraduate student, so we’d been collaborators for quite some time.  He was on my doctoral thesis committee and we remained colleagues and collaborators even after I graduated.  I was in his office one day and there was this FRESIP report on his desk, and it caught my eye. 

I started reading more about it, about this transit photometry technique.  The first thing I thought to myself was how are they going to detect an earth transiting a sun when you’ve got spots that are even larger than the earth going across the face?  That’s crazy, right?  So, I started thinking about it and reading about it.  The number of planet detections was growing, and it was inspiring to watch….  After I finished my thesis, and I took a post-doc in Brazil where my husband was working.  Toward the end of my fellowship, I sent an email to Bill Borucki.  I said I’d been thinking about the effects of stellar activity on planet detection and that it was an area I’d like to explore further.   He wrote me back and invited me to submit a proposal to come out as an NRC postdoc.  That’s what I did.  I visited NASA Ames in October and started work in March of the following year — February or March of 2000.

When I arrived, they were writing the 2000 proposal.  And so, one of the first things I did was help to revise the section on stellar variability.  We know how stars behave as they age, especially the late type stars.  We know that as they age, they spin down and their magnetic fields get weaker.  Therefore, their activity-driven variability decreases.  So, just based on empirical laws and an estimate of the stellar population we’d be looking — the age and temperature distribution be of the stars  — we made a prediction that about 30% of the stars we’d observe would be too young and, therefore, magnetically active that planet detection would be difficult or even impossible.   We included these predictions in the proposal and argued that there were still enough quiet stars to accomplish the mission objectives.  My colleague Jon Jenkins did a study based on the solar variability in the SOHO data that we had.  From a signal detection standpoint, he showed that we can detect a planet as small as the Earth around the Sun given its variability.  So, we put all those pieces together– earths around sun-like stars are detectable and sufficient numbers of stars are expected to be as quiet as the Sun — and I think that it was a strong contribution to the proposal. People like [SMD AA] Ed Weiler, who has a background in stellar astrophysics, had expressed the same skepticism that I had expressed as a graduate student with regards to the detectability of earth-sized planets using transit photometry. 

When did you hear about selection?

I heard about selection after I had put in an application for a faculty position at San Jose State…. We heard about selection in December of 2001, and then I was called for the SJSU interview in January.  It was a tough decision. 

Did the fact that the mission was delayed factor at all into your decision to go ahead and go?

No, my love for teaching and the stability of the job at San Jose State attracted me….  My first year on the faculty, I was given a significantly reduced teaching load.  And so I was able to spend at least two days a week at Ames, and then the other three at San Jose State.  I did that for the first few years because I needed to build a teaching reputation to go through the retention and tenure process.  So, I invested time in my teaching but I was still able to work part time at Ames.  As the mission progressed, things really got busy.  I decreased my teaching load as much as I could.

Now, what was your role on the Kepler mission?

Oh, goodness, it’s been so many different things.  In the early years, after doing this work on the proposal, I became heavily involved with the robotic observatory at Lick Observatory that we were building, Vulcan. It was our ground based prototype for Kepler.   I conceived my fourth child while I was an NRC post doc before I was hired at San Jose State.  Bill was really, really accommodating.  I was able to work on the observatory and run the observations a lot from home, and that really helped a lot.  So, in those early years, I took responsibility for the Vulcan telescope and the observations that we were collecting and the analysis of that data.  But then, as the mission ramped up, around 2004, I started to shift a little bit.  I did a study to optimize the field of view that we would point the telescope at. We discovered that the science yield would be higher if we pointed a little bit off the galactic plane just to get out of the glare of the giants that contaminate the field. 

And then, after we chose the field of view, our job was to figure out of the 4.5 million stars that are in the field of view, which 170,000 are we actually going to observe.  That was a huge effort.  We didn’t appreciate that it was going to be so tough.  So, that really occupied me from probably 2006 until launch (2009).

Does it matter where you are [to do the work as a science team member]?  Is co-location really important?

Not at all!  Tim Brown, and Dave Monet, for example, who are Co-Is, headed up the entire pre-launch stellar classification program.  The nuts and bolts of the photometry and the instrument and the software pipeline to analyze the data–that’s all done at Ames, and the team there is very small.  We have a small number of people that slog through the pipeline products and identify the best planet candidates to forward on to our follow up team.  That’s been occupying a lot of our time more recently.

So, how do you possibly get all of that done with such a small team?

You work around the clock, and that’s been very challenging for me.  My kids are older now, but they still need strong support—[Batalha has four children; the youngest is 8].

Does she think what you do is amazing?

She got to go to the launch.  The other kids did too, but she was especially impressed by it, yes.  She’s been pretty fascinated with rockets ever since that.  So, she does seem to have some appreciation for what I do.  She thinks it’s exciting.  But, of course, at that age, that’s no compensation for having mom at home, right?

Have there been tradeoffs?

Oh, of course, of course.  You know, when we were young and optimistic and naïve, our mothers told us that we could do everything, and that was kind of a white lie.  It was a bit  of a shock when I realized that.  I had my children relatively young.   I went into labor with my first child the night that I took my last final exam at Berkley. [laughter] Yeah, that night.  So, my first three were born during graduate school.  That was a complicated time in terms of money and resources and health insurance and things like that.  But, in retrospect, it was a really flexible time for me.  So, it was kind of a good time to have kids.  I could have my summer off if I wanted.  I mean, there was pressure, of course.  I didn’t achieve as much and work as many hours. I didn’t publish as many papers and all of that.  But I didn’t care….  When the kids got to be about two and a half or three, we put them into a preschool part time for a few hours every day.  But, no, we’ve always staggered our schedule so that somebody could be home with the kids.  We felt that that was very important….  My husband, especially, sacrificed a lot.  There were times he’d wake up at three in the morning and work until noon and then come home and take care of the kids while I worked in the afternoon/evening.   I mean, it was not easy.  Looking back on it, I think I was crazy. [laughter]

But, you made it work and you made it work in your own way.  I think that’s inspiring.

You live it one day at a time and do what you’re comfortable with. 

Natalie Batalha is now the Deputy Science Team Director of the Kepler mission.

Batalha’s 11 peer-reviewed publications in 2010 include:

Batalha, Natalie M. et al. Selection, Prioritization, and Characteristics of Kepler Target Stars. Ap. J. Lett. 713(2):L109-L114 (2010).

Batalha, Natalie M. et al. Pre-spectroscopic False-positive Elimination of Kepler Planet Candidates. Ap. J. Lett. 713(2):L103-L108 (2010).

Koch, David G. et al. Kepler Mission Design, Realized Photometric Performance, and Early Science. Ap. J. Lett. 713(2):L79-L86 (2010).

Borucki, William J. et al. Kepler-4b: A Hot Neptune-like Planet of a G0 Star Near Main-sequence Turnoff. Ap. J. Lett. 713(2):L126-L130 (2010).

Koch, David G. et al. Discovery of the Transiting Planet Kepler-5b. Ap. J. Lett. 713(2):L131-L135 (2010).

Dunham, Edward W. et al. Kepler-6b: A Transiting Hot Jupiter Orbiting a Metal-rich Star. Ap. J. Lett. 713(2):L136-L139 (2010).

Latham, David W. et al. Kepler-7b: A Transiting Planet with Unusually Low Density. Ap. J. Lett. 713(2):L140-L149 (2010).

Rowe, Jason F. et al. Kepler Observations of Transiting Hot Compact Objects. Ap. J. Lett. 713(2):L150-L154 (2010).

Borucki, William J. et al. Kepler Planet-Detection Mission: Introduction and First Results. Science 327(5968):977 (2010).