190Views49Replies

Author Options:

Photograph of extra-solar planetary system! Answered

An article in Science News today shows an infrared image of HR 8799 with three roughly Jupiter-sized planets around it! The speckling in the center (around the "+") is the star.

The same article shows two Hubble images of Fomalhaut taken 18 months apart. The two images show directly the orbital motion of a previously detected planet, Fomalhaut b.

Update (10:12 pm PST 13 Nov 2008): I've attached the two pictures from the SN article. The first is the IR composite of the three-planet system HR 8799; the second is Fomalhaut, showting the offset of Fomalhaut b between 2004 and 2006. I encourage you to read the actual article to get the details of how the data was obtained, and to judge for yourselves its veracity.

Update (12:05 pm PST 14 Nov 2008): The two articles are out in today's ''Science'' along with a news article and editorial (requires subscription).

HR 8799: Morois, et al.
Fomalhaut: Kalas, et al.

Discussions

0
None
Lftndbt

9 years ago

Is the universe shrinking, or is it just me?

0
None
kelseymhLftndbt

Reply 9 years ago

It's just you: the rest of us are expanding --- or our pants sizes are....

0
None
Lftndbtkelseymh

Reply 9 years ago

Are you getting a bit excited?

0
None
kelseymhLftndbt

Reply 9 years ago

No, just older and fatter...happens in your forties....

0
None
LftndbtLftndbt

Reply 9 years ago

Wait.... that's not funny. I'll be forty one day. Doh!

0
None
kelseymh

9 years ago

There's a new preprint claiming observation of a Jovian-mass planet orbiting at 8 AU around beta Pictoris. The image was acquired using image-subtraction techniques, and it isn't yet clear whether the object is a true planet, a coincidental alignment, or an instrumental artifact.

0
None
GorillazMiko

9 years ago

Recently I have been IN LOVE with astronomy. I think I'm going to make a group.

0
None
kelseymhGorillazMiko

Reply 9 years ago

Thanks for following up, and discovering the existing groups! If people aren't participating in them, make some noise: announce there existence with a forum topic under Science; see who are already members and PM them to see why they aren't contributing; and so on. That's what I did with Plasmana's Physics Group.

Your last reference to Science Daily is broken. Your text says "!http://www.sciencedaily.com", but you set the hyperlink URL to "!http://smouch.net/lol". If you did this on purpose, too bad :-) I always check the URL via mouse-over before clicking.

The site is great for general science article! I tend to focus on physics, for obvious reasons :-)

0
None
Lithium Rainkelseymh

Reply 9 years ago

I promise to personally track down and throttle the next man to post a rickroll link. Seriously. Don't think I won't.

0
None
kelseymhLithium Rain

Reply 9 years ago

Hey, that's kind of sexist of you, now isn't it? What if the next f-ing rickroll link is posted by a female? Are you not going to throttle her? Geez...every day, I feel more and more persecuted as the Old White Guy :-(

0
None
Lithium Rainkelseymh

Reply 9 years ago

Don't go all postal on me. It's just a figure of speech. Yeesh. Of course I'd throttle a female RRer.

0
None
kelseymhLithium Rain

Reply 9 years ago

Mmmm....Postal....Nah, I think the bullets would get there three days late and all folded in half ;-/

0
None
Lithium Rainkelseymh

Reply 9 years ago

Tell me about it. they mangled my sculpey hand terribly...

0
None
NachoMahmakelseymh

Reply 9 years ago

. It's different when wimmen do it. Any married man should know that.

0
None
GorillazMikokelseymh

Reply 9 years ago

Hmm. When I hove the links, they never show the sites. I bet you clicked it. :)

0
None
kelseymhGorillazMiko

Reply 9 years ago

Depends on your browser. Safari doesn't show that information. FireFox, which I use, shows the URL down in the very bottom of the window, below the horizontal scrollbar. I'm not familiar with IE.

0
None
n8mankelseymh

Reply 9 years ago

Another smouch bites the dust.

0
None
Sandisk1duo

9 years ago

Well, too bad it is millions of light years away.. :(

0
None
kelseymhSandisk1duo

Reply 9 years ago

Umm, no. Fomalhaut is only 25 light years away, and HR 8799 is still within the Milky Way, probably no more than a couple hundred ly. Farther than that, and the angular size is too small to image this way.

0
None
Sandisk1duokelseymh

Reply 9 years ago

well, if a space craft was traveling 1/4 the speed of light, it would take 100 years to reach the planet

0
None
kelseymhSandisk1duo

Reply 9 years ago

In whose frame of reference? Homework problem...work out how long the trip would be for the people in that space craft, assuming only special relativity (don't worry about gravity, or about stopping or starting). Post the answer here.

0
None
Sandisk1duokelseymh

Reply 9 years ago

ok, i'm not that GREAT at math, but 4 (times) 25 = 100
you are going at 1/4th the speed of light...
(not inside the space craft)

so, ya

so, presuming time stops at the speed of light, they would feel that 25years has passed, if my math is right, of course

0
None
kelseymhSandisk1duo

Reply 9 years ago

No, that's the point of relativity -- the people in the ship feel that time passes at a different rate than for outside observers, in particular tShip = tEarth×sqrt(1-ß2), where ß = v/c.

In this case, you have ß = 1/4, so tship = 100 × sqrt(15/16) = 24.2 years. Not a great difference, but you can see that it's not 25.

Suppose you had the ship travelling at 1/2 the speed of light (not unreasonable for a solar sail). Then tEarth = 50 years, but tShip = 50 × sqrt(3/4) = 43.3 years. That's almost seven years "shorter," as seen by the people taking the trip.

0
None
kelseymhkelseymh

Reply 9 years ago

Minor correction to my second paragraph (argh). Change 24.2 to 96.8 (I multiplied by 25, not by 100). The sqrt(15/6) is correct. The whole thing should read:

... = 96.8 years. Not a great difference, but you can see that it's not 100 years.

0
None
Sandisk1duokelseymh

Reply 9 years ago

well, being a sophomore, taking chemistry, and algebra 2, i don't know the Speed of light constant and other stuff, so i can't really calculate what i don't know

0
None
NachoMahmaSandisk1duo

Reply 9 years ago

. According to Google, "the speed of light = 299 792 458 m / s"
. Wikipedia agrees and also gives it as "≈ 6.71×108 miles per hour" (671,000,000 mph) and ≈ 186 000 miles per second (that's the one that sticks in my head).
. None of those figures really mean much to me - anything over about 200 mph is just really-freaking-fast in my head. ;)

0
None
kelseymhNachoMahma

Reply 9 years ago

"the speed of light = 299 792 458 m / s" On a side note, that number is ''defined'' as the speed of light. The meter is now defined as 1/299792458 of the distance light travels in one second in vacuum, so if someone comes up with a more accurate measurement of c what will really happen is that the meter's length will change :-) (presumably by less than 3 billionths).

0
None
Sandisk1duoNachoMahma

Reply 9 years ago

3.0 x 10? meters per second is what my teacher told me, bu ti can't remember the exponent

0
None
Sandisk1duoSandisk1duo

Reply 9 years ago

i assumed that if you went 1/4 the speed of light, time would go by 4 times faster Solar sail, can you explain this concept?

0
None
Sandisk1duokelseymh

Reply 9 years ago

Too many formulas with too many symbols that i do not comprehend

0
None
NachoMahmakelseymh

Reply 9 years ago

. Using 1/(1 – (v/c)2)1/2, I come up with a time-dilation factor of a little over 3%. So it would take a little over 96 years, subjective time, to travel 100 ly @ 0.25c.
. You have to get to over 0.4c to get 10% and 0.6c gives 25%. You have to get over 0.85c to experience time at half-speed. Ie, one has to be hauling butt to get much dilation.

0
None
kelseymhNachoMahma

Reply 9 years ago

Your answer was right the first time, you just wrote the description wrong :-). It would take 96.8 subjective (ship-board) years to travel 25 ly @ 0.25c. Alex was computing 100 years, Earthbound, for the same 25 ly trip.

0
None
NachoMahmakelseymh

Reply 9 years ago

. I feel pretty good about picking the proper equation. Not too shabby for S AR oilfield trash. ;)

0
None
kelseymh

9 years ago

I've added links to the original journal articles, published today (online) in ''Science''.

0
None
Tool Using Animal

9 years ago

Stop! Lest ye arouse Cthugha from his ancient sleep!

0
None
bumpus

9 years ago

..INTERGALACTIC PLANETARY..
..PLANETARY INTERGALACTIC..

:D