Planets in ALF Cen officially real

General physics and astronomy discussions not directly related to Celestia
Avatar
Chuft-Captain
Posts: 1779
Joined: 18.12.2005
With us: 15 years 2 months

Re: Planets in ALF Cen officially real

Post #21by Chuft-Captain » 13.11.2012, 06:14

Hi Buggs,

Welcome back. It's been a long time! I'm sure I'm not the only one here who's missed your beautiful addons.

Have a look at my Castor addon:
HERE: http://shatters.net/forum/viewtopic.php?f=6&t=12104&p=111564#p111564
or HERE: http://www.celestiamotherlode.net/catalog/show_addon_details.php?addon_id=1281
for an example.
I can't guarantee I'm done everything correctly (Grant's prob the best judge of that) but it might be useful as an example.
Doesn't include any planets (if that's where your confusion is).
I have placed some planets in this system in the past, but they are not included in the download... (and I suspect that this is not what you're trying to achieve anyway,as you've already said that you successfully placed a planet around a barycenter.)

FWIW,
Here's an example of Earth placed in orbit around the "Castor A" barycenter:

Code: Select all

"Earth@Castor A" "Castor A" 
{
....
}

and in orbit around the "Castor B" barycenter:

Code: Select all

"Earth@Castor B" "Castor B" 
{
....
}

which looks like this in Celestia (CLICK for fullsize):
Earth@Castor A and B (labels).jpg

CC
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

Avatar
Chuft-Captain
Posts: 1779
Joined: 18.12.2005
With us: 15 years 2 months

Re: Planets in ALF Cen officially real

Post #22by Chuft-Captain » 13.11.2012, 09:21

Buggs,

I just replicated Earth @ 40 Eri A using the same method as for Castor, so it looks like you don't need to worry about HD or HIP numbers at all.

Looks like this, with Eri B + C in the background:
Earth@40 Eri A.jpg


Here's the SSC:
cc_40 Eri A Earth.zip


URL for the viewpoint above...
cel://Follow/Keid%20A/2012-11-13T09:02:41.28804?x=AADwebQRvX0wAQ&y=AAAkTmhpsKNJ&z=AAC4k1pnmv2g&ow=-0.775286&ox=0.0751883&oy=0.519295&oz=0.351583&select=Keid%20A:Earth%4040%20Eri%20A&fov=36.5328&ts=1&ltd=0&p=0&rf=2180019&lm=4227&tsrc=0&ver=3
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

buggs_moran
Posts: 835
Joined: 27.09.2004
With us: 16 years 4 months
Location: Massachusetts, USA

Re: Planets in ALF Cen officially real

Post #23by buggs_moran » 13.11.2012, 13:48

I did end up getting it to work. I must have had a syntax error in my ssc. I has been a LONG time.
Homebrew:
WinXP Pro SP2
Asus A7N8X-E Deluxe
AMD Athlon XP 3000/333 2.16 GHz
1 GB Crucial RAM
80 GB WD SATA drive
ATI AIW 9600XT 128M

Reiko
Posts: 1119
Joined: 05.10.2006
Age: 37
With us: 14 years 4 months
Location: Out there...

Re: Planets in ALF Cen officially real

Post #24by Reiko » 13.11.2012, 22:01

It's a shame that we do not yet have the technology to send a probe to aCen. with a trip time of 20 years or less.

chornedsnorkack
Posts: 13
Joined: 19.03.2013
With us: 7 years 11 months

Re: Planets in ALF Cen officially real

Post #25by chornedsnorkack » 11.04.2013, 16:23

How would you estimate the maximum elongation and visual magnitude of Bb from a planet, say Bc, in habitable zone of B?

Maximum elongation is the easier part. Do I get the Bb semimajor axis right at 0,042 AU?

Then, the habitable zone is 0,7 AU... maximum elongation would be around 3 and a half degrees.

But what could the visual magnitude of Bb be at maximum elongation (half phase)?

Avatar
t00fri
Developer
Posts: 8772
Joined: 29.03.2002
Age: 18
With us: 18 years 10 months
Location: Hamburg, Germany

Re: Planets in ALF Cen officially real

Post #26by t00fri » 11.04.2013, 18:00

chornedsnorkack wrote:How would you estimate the maximum elongation and visual magnitude of Bb from a planet, say Bc, in habitable zone of B?

Maximum elongation is the easier part. Do I get the Bb semimajor axis right at 0,042 AU?

Then, the habitable zone is 0,7 AU... maximum elongation would be around 3 and a half degrees.

But what could the visual magnitude of Bb be at maximum elongation (half phase)?

How about calculating it yourself? You obviously know how to do the estimate.
This is not a school class...
Moreover, the known Bb orbit parameters (semi-major axis,...) are already included in Celestia's latest extrasolar.ssc data file. Data from here http://exoplanet.eu/catalog/alf_cen_b_b/
You can simply simulate the orbit in Celestia and measure out the results that interest you or vary unknown parameters and study their effects...

Fridger
Image

chornedsnorkack
Posts: 13
Joined: 19.03.2013
With us: 7 years 11 months

Re: Planets in ALF Cen officially real

Post #27by chornedsnorkack » 11.04.2013, 20:19

It is quite irritating how exoplanet.eu and many other sources give the period with 4 significant figures - but then semimajor axis with 1.
Given that the mass of B has 3 significant figures but the last is uncertain, I got 2 figures for the axis and it was 0,042 AU.

The distance between Bb and Bc at maximum elongation turns out to be very close to the distance between Earth and Venus.

Now, the illumination of Bb should be about 135 times the illumination of Venus.

The uncertain parts are the actual diametre and albedo of Bb.

CharlottAwong
Posts: 8
Joined: 29.10.2016
With us: 4 years 3 months

Post #28by CharlottAwong » 29.10.2016, 13:21

Indeed, this was a great news.


Return to “Physics and Astronomy”

Who is online