2011 HM₁₀₂: A new companion for Neptune

This month my latest paper made it to print in the Astronomical Journal. It's a short piece that describes a serendipitous discovery that my collaborators and I made while searching for a distant Kuiper Belt Object for the New Horizons spacecraft to visit after its 2015 Pluto flyby. Last October, at the annual American Astronomical Society Division of Planetary Sciences meeting, I gave a talk about this neat little object we discovered. Now that the paper is out, I thought it might be interesting and fun to assemble a blog post around the slides I prepared for that talk. So without further ado, I give you:

So, what kind of serendipitous discovery did we make? We found a Neptune Trojan, now called 2011 HM102! And it's not just any Neptune Trojan: it makes a list of superlatives. It's the largest trailing Trojan known in the entire Solar System, it's the most inclined Neptune Trojan known, and (as of right now) it is the closest known object of any kind to the New Horizons spacecraft! Read on to learn about how we found 2011 HM102 and what we have learned about this remarkable little world.

Flying from Kepler-62 e to Kepler-62 f

Today NASA announced the discovery of two potentially-habitable planets orbiting a single star. The star is designated Kepler-62, and these two planets are referred to by their place in the five-planet system - e is planet four and f is planet five (a is reserved for the host star).

These planets are both quite small - 1.4 and 1.6 times the radius of the Earth, respectively. In addition, they're both located at relatively comfortable distances from their host star. Depending on what their atmospheres are like, they could potentially host conditions on their surfaces that are amenable to life.

But two planets in (or near) a single star's habitable zone? That made me wonder - if a civilization arose on one of the two planets, how difficult would it be for them to visit the other planet?

#NaPoWriMo

Day 30: Until next time.


Thirty days written:
Worlds in words with friends in prose
under spring skies.

                                          

Day 29: Challenge


not lost.
simply unseen.
out in the deep star-fields
slow-plying, so come, look again:
find me.

                                          

Day 28: Zeroth Order

scratch a few 

marks on a page

trace the big picture

in broad strokes

with small lines

nevermind the human

ephemera

that fills each dt

no matter how minute

they fall out trivially

in the end

anyway.

How big do stars look from habitable planets around them?

Standing on a habitable alien world, how big would that planet's host star look overhead? After a quick Googling, I didn't come up with any nice summaries. So I snagged Allen's Astrophysical Quantities and did a couple quick calculations.

This figure is the result, showing the apparent sizes of stars as seen from hypothetical habitable planets. around them, all scaled to the size our Sun appears in the Earth's sky. The estimates are fairly crude; I just approximated the distance at which the (bolometric) flux from each star would be equal to that which Earth sees from the Sun. This ignores complicating factors like effective albedo changes due to different peak wavelengths produced by each star, or tidal locking for close-in planets around the lowest-mass stars.

I added the approximate masses of a few notable stars on the left-hand side. Only a couple of these are known to have planets. 

New 500px photography account

I have not created any strictly photography-related posts yet. I plan remedy this soon, and to get the ball rolling I have created a 500px account to host my photography.

At this point, I have only uploaded a sample of my photography from the last few years, but feel free to peruse: http://500px.com/alexhp

A couple examples below the fold.

Observatory Interior: Interactive Panorama!

Have you ever wondered what the inside of a world-class observatory looks like?

On a run at the Magellan Baade 6.5-meter observatory in Chile last year, I took a full 4π steradian spherical panorama of the dome interior using Photosynth on my iPhone. The result is the interactive, scrollable panorama below:




Below the telescope you can see two of my colleagues coming down from one of the instrument platforms; they are both well over 6' tall and make good scale references. This is a huge machine.

I will post later about some of the data we collected on that run. Spoiler: Neptune has a new friend!

Alex H. Parker

Planetary Popularity

I have wanted to do something with the Google n-gram data for a while, and I've finally caved.

For those who haven't seen it yet, the Google n-gram browser allows you to see and compare the historic popularity of various phrases in books throughout history.

The default browser is fun and fast to play with, but I decided to take a crack at some of the raw data.

How about comparing the popularity of various planets (including the now-dwarf planet Pluto) in literature across the last few hundred years?

I give you "Planetary Popularity in Recent History:"

Click to enlarge!

Details and a little interpretation below the fold.