Another new planetary system imaged

On 2009-12-06, Gordon Stangler wrote:
Looking at star maps, it is not that far off from Draco, Ursa Minor,
and Ursa Major. Kepler may be able to see divert some attention that
way.

Kepler will be imaging the same section of sky for its lifetime.

On Dec 5, 10:17*pm, Dan Birchall
wrote:
(Yousuf Khan) wrote:
*Gordon Stangler wrote:
I imagine that Kepler will take a look at the system when it gets a
chance. *After all, 51 light years is really just a hop, skip and jump
from here.

*Is Kepler even looking at that direction? Kepler points only towards
*Cygnus, Lyra, & Draco constellations. Where is GL 578 located,
*constellation wise?

GJ 758 (oft mis-typed as GL 758) is in Lyra, according to Wikipedia:http://en.wikipedia.org/wiki/GJ_758- but I'm not sure how many of the
actual science targets for the project are.

This is likely only the first of many announcements, since it was
found during instrument engineering prior to the official start this
October of the 5-year SEEDS (Strategic Exploration of Exoplanets
and Disks) project.

The target section of that project includes - see section 2 ofhttp://www.naoj.org/Science/SACM/Senryaku/SEEDSProposal070731submit.pdf
- looking for planets around 100 stars within 100 light years of earth,
as well as 236 more wthin 650 light years, and looking for protoplanetary
disks around another 185 planets within 650 light years.

I wasn't at the summit during either of the SEEDS engineering runs
where they looked at GJ 758, but I'm the scope operator for the first
seven nights of SEEDS (which totals 120 nights over 5 years) - three
over Halloween weekend, and four more during Christmas week. *Seen
some pretty trippy pictures on the observer consoles. *(Everything's
in psychedelic rainbow false-color. *I'm hoping to do a lot more
operating for the project over the years.

-D

--
djb@ | Dan Birchall, Night Operation Assistant, Subaru Telescope/NAOJ.
naoj | Views I express are my own, certainly not those of my employer.
.org | Oh wicked, bad, naughty, _evil_ Dan! *He is a _naughty_ person.

Hi Dan, thanks for the info. I will update my blog.

BTW, did you post this info to Fark.com? That's where I got my link
from

On Dec 5, 11:17*pm, Dan Birchall
wrote:
[...]
GJ 758 (oft mis-typed as GL 758) is in Lyra, according to Wikipedia:http://en.wikipedia.org/wiki/GJ_758- but I'm not
[snip]

(Nit police) Actually, it is not mis-typed--all Gliese catalog entries
915 and below are GLxxx. Above--GJxxx

On Fri, 4 Dec 2009 23:02:56 -0800 (PST), Gordon Stangler
wrote:

From http://aitj-co.com/gcsgz5/blog/?p=693 and
http://www.eurekalert.org/pub_releas...-tus120109.php.

A new star system with planets, GL 578 b was directly imaged using the
Hawaii based Subaru telescope, a Princeton news press blares. GL 578
b is a star 51 light years away, with a slightly larger then Jupiter
sized planet in a Jupiter sized orbit, leaving hope for Earth like
planets orbiting the Sun-like star.

I imagine that Kepler will take a look at the system when it gets a
chance. After all, 51 light years is really just a hop, skip and jump
from here.

Just one second. If Kepler is moving directly toward GJ578 at, say, 20
km per second, wouldn't it take 15,000 years just to move closer by
one light year, from 51 down to 50? 51 ly is a long distance. Kepler
is no better off than we are! (Pioneer 10 is moving at 12 km per
second).
Based on TV history, if there were aliens listening in on GL 578 b,
they could be watching Captain Kangaroo, or the first re-runs of I
Love Lucy. One should note that the appearance of aliens at GL 578 b
could be answered soon, for if they started broadcasting signals back
at us when they started getting our signals, we could get their
signals as early as 2029, 102 years after the first TV broadcasts.
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.
How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

John Polasek wrote:
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.

HIPPARCOS measured its proper motion to about 1 milliarcsecond per year
(about 0.5 percent), so we know to a small fraction of an arcsecond
"where it is now," which of course is where it will appear to be in 51
years.

How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

No, the annual parallax is 0.05070 +/- 0.00076 seconds of arc, again as
measured by HIPPARCOS. In other words, we know its distance to not
quite 1 percent accuracy. That's not shabby for an object 51 ly away.
GAIA will of course get it even better.

-- Bill Owen

On Tue, 08 Dec 2009 14:16:53 -0800, Bill Owen
wrote:

John Polasek wrote:
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.

HIPPARCOS measured its proper motion to about 1 milliarcsecond per year
(about 0.5 percent), so we know to a small fraction of an arcsecond
"where it is now," which of course is where it will appear to be in 51
years.

How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

No, the annual parallax is 0.05070 +/- 0.00076 seconds of arc, again as
measured by HIPPARCOS. In other words, we know its distance to not
quite 1 percent accuracy. That's not shabby for an object 51 ly away.
GAIA will of course get it even better.

-- Bill Owen
The angle I get this time for the full six-month parallax using 51ly
is
93e6*2 mi/51LY*2.06e5sec/rad = .128 seconds
Or, If you are talking one legged parallax, equals 0.064. that's for
51 ly. Using your figure .0507 places it about 25% farther then 51 ly
or
51*.064/.0507 = 64.4 ly
I'm no expert at this but it's looking like there is a 25% error in
the distance and you're talking about a 1% error. The HIPPARCOS angle
is probably correct but the conversion to 51 ly appears wrong.

I think I made an important point, which you clipped and did not
address. So I'll say it again. Kepler would take 15,000 years just to
make a 2% improvement in range from 51 to 50 light years so it's not
just a hop and a skip as someone said. Maybe Hubble should look.
John Polasek
..

John Polasek wrote:
On Fri, 4 Dec 2009 23:02:56 -0800 (PST), Gordon Stangler
wrote:

From http://aitj-co.com/gcsgz5/blog/?p=693 and
http://www.eurekalert.org/pub_releas...-tus120109.php.

A new star system with planets, GL 578 b was directly imaged using
the Hawaii based Subaru telescope, a Princeton news press blares.
GL 578 b is a star 51 light years away, with a slightly larger then
Jupiter sized planet in a Jupiter sized orbit, leaving hope for
Earth like planets orbiting the Sun-like star.

I imagine that Kepler will take a look at the system when it gets a
chance. After all, 51 light years is really just a hop, skip and
jump from here.

Just one second. If Kepler is moving directly toward GJ578 at, say, 20
km per second, wouldn't it take 15,000 years just to move closer by
one light year, from 51 down to 50? 51 ly is a long distance. Kepler
is no better off than we are! (Pioneer 10 is moving at 12 km per
second).
Based on TV history, if there were aliens listening in on GL 578 b,
they could be watching Captain Kangaroo, or the first re-runs of I
Love Lucy. One should note that the appearance of aliens at GL 578 b
could be answered soon, for if they started broadcasting signals back
at us when they started getting our signals, we could get their
signals as early as 2029, 102 years after the first TV broadcasts.
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.
How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

I can see why you are puzzled.

Also known as 45 Boo, a 5th mag F5V star.

The Hipparcos parallax for this star is 0.0507 arcsec or 51 mas, near
enough. I suspect the press release or article author confused the parallax
(in mas) with the distance (in LY).

For a parallax p = 0.0507 arcsec, d = 1/p in parsec, or 19.72 pc. This
converts to 64.3 LY. (3.26 LY/pc, unless my memory is going). The error
given is about 1.5%.

So the programmes being viewed by the aliens ought to be 1955-56 vintage.
Milton Berle, Jackie Gleason, Ed Sullivan, Captain Kangaroo, I Love Lucy,
etc. And lots of old films. Sound about right? If they are picking up
early BBC TV, lots of interval stuff with potter's wheels, and next year
they will get the first Patrick Moore "Sky at Night" broadcast.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

On Wed, 9 Dec 2009 08:50:49 -0000, "Mike Dworetsky"
wrote:

John Polasek wrote:
On Fri, 4 Dec 2009 23:02:56 -0800 (PST), Gordon Stangler
wrote:

From http://aitj-co.com/gcsgz5/blog/?p=693 and
http://www.eurekalert.org/pub_releas...-tus120109.php.

A new star system with planets, GL 578 b was directly imaged using
the Hawaii based Subaru telescope, a Princeton news press blares.
GL 578 b is a star 51 light years away, with a slightly larger then
Jupiter sized planet in a Jupiter sized orbit, leaving hope for
Earth like planets orbiting the Sun-like star.

I imagine that Kepler will take a look at the system when it gets a
chance. After all, 51 light years is really just a hop, skip and
jump from here.

Just one second. If Kepler is moving directly toward GJ578 at, say, 20
km per second, wouldn't it take 15,000 years just to move closer by
one light year, from 51 down to 50? 51 ly is a long distance. Kepler
is no better off than we are! (Pioneer 10 is moving at 12 km per
second).
Based on TV history, if there were aliens listening in on GL 578 b,
they could be watching Captain Kangaroo, or the first re-runs of I
Love Lucy. One should note that the appearance of aliens at GL 578 b
could be answered soon, for if they started broadcasting signals back
at us when they started getting our signals, we could get their
signals as early as 2029, 102 years after the first TV broadcasts.
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.
How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

I can see why you are puzzled.

Also known as 45 Boo, a 5th mag F5V star.

The Hipparcos parallax for this star is 0.0507 arcsec or 51 mas, near
enough. I suspect the press release or article author confused the parallax
(in mas) with the distance (in LY).

For a parallax p = 0.0507 arcsec, d = 1/p in parsec, or 19.72 pc. This
converts to 64.3 LY. (3.26 LY/pc, unless my memory is going). The error
given is about 1.5%.

So the programmes being viewed by the aliens ought to be 1955-56 vintage.
Milton Berle, Jackie Gleason, Ed Sullivan, Captain Kangaroo, I Love Lucy,
etc. And lots of old films. Sound about right? If they are picking up
early BBC TV, lots of interval stuff with potter's wheels, and next year
they will get the first Patrick Moore "Sky at Night" broadcast.
So that's handy for rough work: 1.25LY/milliarcsec, just as 3 LY to 1
parsec IIRC. Alpha Centauri 4LY, about 1.3 psec and 3.2mas.
Why don't we know more about Alpha Centauri? Images are smudges.
John Polasek

On Wed, 09 Dec 2009 10:07:27 -0500, John Polasek
wrote:

On Wed, 9 Dec 2009 08:50:49 -0000, "Mike Dworetsky"
wrote:

John Polasek wrote:
On Fri, 4 Dec 2009 23:02:56 -0800 (PST), Gordon Stangler
wrote:

From http://aitj-co.com/gcsgz5/blog/?p=693 and
http://www.eurekalert.org/pub_releas...-tus120109.php.

A new star system with planets, GL 578 b was directly imaged using
the Hawaii based Subaru telescope, a Princeton news press blares.
GL 578 b is a star 51 light years away, with a slightly larger then
Jupiter sized planet in a Jupiter sized orbit, leaving hope for
Earth like planets orbiting the Sun-like star.

I imagine that Kepler will take a look at the system when it gets a
chance. After all, 51 light years is really just a hop, skip and
jump from here.

Just one second. If Kepler is moving directly toward GJ578 at, say, 20
km per second, wouldn't it take 15,000 years just to move closer by
one light year, from 51 down to 50? 51 ly is a long distance. Kepler
is no better off than we are! (Pioneer 10 is moving at 12 km per
second).
Based on TV history, if there were aliens listening in on GL 578 b,
they could be watching Captain Kangaroo, or the first re-runs of I
Love Lucy. One should note that the appearance of aliens at GL 578 b
could be answered soon, for if they started broadcasting signals back
at us when they started getting our signals, we could get their
signals as early as 2029, 102 years after the first TV broadcasts.
We are not seeing GJ578--only its image as it was 51 years ago. No
telling where it is now.
How did they measure 51 ly-there's no red shift. The six-month solar
parallax is 6.2 seconds of arc. Is that what they did?
John Polasek

I can see why you are puzzled.

Also known as 45 Boo, a 5th mag F5V star.

The Hipparcos parallax for this star is 0.0507 arcsec or 51 mas, near
enough. I suspect the press release or article author confused the parallax
(in mas) with the distance (in LY).

For a parallax p = 0.0507 arcsec, d = 1/p in parsec, or 19.72 pc. This
converts to 64.3 LY. (3.26 LY/pc, unless my memory is going). The error
given is about 1.5%.

So the programmes being viewed by the aliens ought to be 1955-56 vintage.
Milton Berle, Jackie Gleason, Ed Sullivan, Captain Kangaroo, I Love Lucy,
etc. And lots of old films. Sound about right? If they are picking up
early BBC TV, lots of interval stuff with potter's wheels, and next year
they will get the first Patrick Moore "Sky at Night" broadcast.
So that's handy for rough work: 1.25LY/milliarcsec, just as 3 LY to 1
parsec IIRC. Alpha Centauri 4LY, about 1.3 psec and 3.2mas.
Why don't we know more about Alpha Centauri? Images are smudges.
John Polasek
Oops! I barely hit the send key before I realized I had it backwards.
I revise it to LY*mas = 3200. So for AlphaC it's mas = 3200/4 = 800
mas.
John Polasek

In article ,
John Polasek wrote:

snip

I revise it to LY*mas = 3200. So for AlphaC it's mas = 3200/4 = 800
mas.

You've got the idea, although 3260 is a better figure for the constant.
According to Simbad, the Hipparcos parallax for Proxima Centauri is 772
+/- 2 mas; 3260/772 = 4.22 LY. For Rigil Kent it's 742 +/- 1 mas = 4.39
LY.

Note that you can only use this method with precision when the angle is
small, making the simple inverse function a good approximation to the
cosecant.

1 pc = csc(0°0'1") AU ~= 206265 AU.

3600*180/pi ~= 206265.

When calculated to high precision, the above two figures differ by about
one part in 250 billion.

--
Odysseus