High proper motion. Q's

Is there a "speed" (e.g. 1.0 arcsec per year) that defines "high"
proper motion (as opposed to low or medium)?

Limiting to magnitude 18 or brighter (i.e. within reach of most
amateur CCD gear) have all the high proper motion stars been
catalogued, or do any remain to be discovered or at least have their
motion more accurately measured?

If I find a star in one of my images that's moved a lot from its
position on an earlier DSS plate, then how do I find its "known"
proper motion to compare against my results?

A good example is the mag 14.5 star currently at 19 53 24.51, 11 36
07.4 (near NGC6837 in Aquila), as that's what prompted me to ask these
questions.

Is there any scientific value in pursuing and recording these beasts?
Can the amateur contribute as in variable star observing?

Thanks in advance for pointers and help…

Cheers
Beats

I'm not an expert in star movement but it seems to me that any
information gathered would/could be used to further refine any/all star
movements. Also, you may find something unrelated along the way that nobody
else has considered looking for.

The Astronomy Section of the Rochester Academy of Science has a glass
negative taken in 1948(?) displayed. I absolutely love looking at this
thing because of all the stars per inch. I don't have the patients you
apparently have but it would be fascinating to compare this photo to others
taken today of the same region.

--
Michael A. Barlow
"justbeats" wrote in message
m...
Is there a "speed" (e.g. 1.0 arcsec per year) that defines "high"
proper motion (as opposed to low or medium)?

Limiting to magnitude 18 or brighter (i.e. within reach of most
amateur CCD gear) have all the high proper motion stars been
catalogued, or do any remain to be discovered or at least have their
motion more accurately measured?

If I find a star in one of my images that's moved a lot from its
position on an earlier DSS plate, then how do I find its "known"
proper motion to compare against my results?

A good example is the mag 14.5 star currently at 19 53 24.51, 11 36
07.4 (near NGC6837 in Aquila), as that's what prompted me to ask these
questions.

Is there any scientific value in pursuing and recording these beasts?
Can the amateur contribute as in variable star observing?

Thanks in advance for pointers and help.

Cheers
Beats

(justbeats) wrote in message om...
asked a number of questions -

Is there a "speed" (e.g. 1.0 arcsec per year) that
defines "high" proper motion (as opposed to low or medium)?

1) What is an "average" proper-motion star?

Abell's _Exploration of the Universe_ (7th Ed.) notes that the average
proper motion of all stars in the Yale Bright Star Catalogue is 0.1"
per year.

2) What is a "large" proper motion star?

Willem Jacob Luyten (1899-1994) research career spanned over 7
decades. His proper motion catalogues defined this area. See bios at:

http://www.phys-astro.sonoma.edu/brucemedalists/luyten/
http://bob.nap.edu/html/biomems/wluyten.html

Many of Luyten's early papers used 0.5" per year as the dividing line
between "average" and "large proper motion" stars. Luyten (1955);
Luyten (1954). The current 2002 version of the _Luyten's Half-Second_
catalogue (LHS) currently contains 4470 stars. Bakos (2002). The
revised LHS can be queried from -

http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/279
http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/279

In 1979, Luyten expanded his earlier half-second proper motion
catalogue of 1849 stars down to 0.2" per year in the _New Luyten
Two-Tenths_ (NLTT) catalogue. This catalogue contains approximately
59,000 stars and can be queried at:

http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/98A
http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/98A

The best current version of the NLTT is Salim (2003). The revised NLTT
can be queried at:

http://cdsweb.u-strasbg.fr/viz-bin/V...J/ApJ/582/1011
http://cdsweb.u-strasbg.fr/cgi-bin/Cat?J/ApJ/582/1011

Salim notes that both his and the orignal NLTT should be consulted
when evaluating any one star.

The USNO-B high proper motion catalogues were the next major advances
in proper motion astrometry. Monet (2003); Gould (2003b). The
USNO-B1.0 proper motion catalogue contains proper motions for
1,045,913,669 stars down to magnitude 21.0 with annual proper motions
.18". They can be queried at:

USNO-B1.0 Proper-motion catalogue - Monet (2003)
http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/284
http://cdsweb.u-strasbg.fr/cgi-bin/Cat?I/284

USNO-B2.0 Proper-motion catalogue - Gould (2003b)
http://vizier.u-strasbg.fr/viz-bin/V...e=J/AJ/126/472
http://vizier.u-strasbg.fr/viz-bin/Cat?J/AJ/126/472

Luyten commented, in passing, in a 1988 paper, that the half-second
and two-tenths standards had historical roots:

"For some strange reason, ever since van Maanen published the first
catalogue of proper motions larger than 0.5 annually, this has become
the lower limit of 'large proper motions' Similarly, when the Royal
Greenwhich Observatory, more than fifty years ago, published the
proper motions of virtually all B.D. stars in the Greenwich zone -
from +64 to +90 - in the Astrographic Catalogue, and stressed
especially, the motions of larger than 0.2 annually, this became the
dividing line between motions which were individually interesting, and
those only statistically interesting."

Luyten (1988) referring to Part 3 of van Maanen's ground-breaking 15
papers on proper motion in Messier galaxies and the Milky Way based on
his work at Mt. Wilson. van Maanen (1938).

See also Table No. 1 in Luyten (1988), showing a distribution of stars
between 0.18" and 0.5" proper motion and between magnitude 8.25 and
11.5.

3) What do professional astronomers call a "high" proper motion star?

Modern proper motion journal articles make little distinction between
"large" and "high" proper motions, or 0.5" as an arbritary dividing
line for "high" annual proper motion. For example, Lepine et al
(2003) refers to all stars in Luyten's NLTT and LHS as "high proper
motion" stars. By his article title, Gould (2003b) refers to all
stars with annual proper motions greater than 0.18" to be "high proper
motion".

4) What is a useful cut-off for amateur observers?

For amateur purposes, I find "large" proper motion most easily
understood as 0.2"-0.5" and "high" proper motion to be 0.5". This is
probably different than the meaning of "high" proper motion in
professional journals.

For amateur backyard astronomy enjoyment, I generally apply 3" as a
useful cut-off limit. Querying the revised LHS catalogue, the
following number of rows are returned at various proper motion
cut-offs:

0.5" 4470
1.0" 597
2.0" 97
3.0" 45
4.0" 22
5.0" 16
6.0" 12

A 3" cut-off simply gives a useable number of stars for an amateur to
work with for viewing enjoyment purposes.

The Millenium Star Atlas lists 22 high proper motion stars using a
cut-off of 3.45" annual proper motion. See -

http://astro.estec.esa.nl/Hipparcos/msa-tab8.html

(For beginner lurkers wanting to see what high proper motion looks
like, see the online simulator at -

http://astro.estec.esa.nl/Hipparcos/...howMotion.html

Use one of the stars in the Millenium Star Atlas, above, in the
simulator.)

Limiting to magnitude 18 or brighter . . . have all the
high proper motion stars been catalogued, or do any remain
to be discovered or at least have their motion more
accurately measured?

Gould (2003a) tested the completeness of the Luyten LHS, NLTT and USNO
B catalogues.

Gould concluded for "high" proper motion stars with annual proper
motions 0.18", for bright stars 11.0v, the NLTT may be 100%
complete for galactic latitudes greater than north or south 15°, but
that its completeness falls to 75% near the galactic plane, "even for
these bright stars. Gould 2003b at 26. In other words, incompleteness
rises to 35% within the 15° of latitude around the galactic plane.

But "for 14.5 V 18.5, . . . incompleteness is 10%. These fractions
rise toward both brighter and fainter magnitudes. . . . It
[incompleteness] also rises to ~ 35% at the Galactic plane, although
this is only determined for relatively bright stars ~ 14." Gould
2003a.

The hunt for all high proper motion stars continues to be refined.
Lepine (2003) using the Sloan Digital Sky Survey, concluded that
Luyten's LHS and NLTT catalgoues were "90% complete in the northern
sky for stars with 0.5 mu 2.0′down to magnitude r=19."
Lepine (2003) also noted that "the LHS and NLTT catalogs are
significantly incomplete in the Southern sky and at low galactic
latitudes, leaving large expanses of the Solar neighborhood that
still are very poorly surveyed for intrinsically faint stars." 57 new
high proper motion stars were found using the SDSS.

If I find a star in one of my images that's moved a lot from its
position on an earlier DSS plate, then how do I find its "known"
proper motion to compare against my results?

Refer to the catalogues listed above - the revised LHS, the revised
NLTT, the original NLTT, the USNO B1.0 catalogue, etc.

I do not know the protocol in event that your suspect star does not
appear in the above catalogues. Maybe more experienced amateurs here
can add a comment based on experience.

Is there any scientific value in pursuing and recording these beasts?

If your suspect star is a main sequence star (not a white drawf or
subdrawf) within 15° of the galactic plane and has magnitude less than
14v, it looks like you have a 1 in 3 chance of forwarding some new
useful information to professional astronomers. Regardless of where
it is located, if your star has a galactic of latitude of greater than
+-15°, you have a 1 in 10 chance of referring a potential "new" high
proper motion star to professional astronomers. These percentages
refer to annual proper motions greater than 0.18".

Can amateurs make a contribution "pursing these beasts." An abstract
from the December 2003 AAS meeting describes the value of high proper
motion stars to professional astronomy this way: "[T]he fastest moving
stars in the sky provides a fundamental database providing insight
about the Sun's neighbors, subdwarfs, and extremely fast moving stars
that might be exiting the Galaxy." Jao (2003).

Enjoy - Canopus

References:

Gould, Andrew. July 2003a. Completeness of USNO-B for High Proper
Motion Stars. AJ 126(1):472-483.
http://cdsads.u-strasbg.fr/cgi-bin/n...J....126..472G
http://fr.arxiv.org/PS_cache/astro-p...01/0301001.pdf

Salim, S., Gould, A. Jan. 2003b. Improved Astrometry and Photometry
for the Luyten Catalog. II. Faint Stars and the Revised Catalog. ApJ.
582(2):1011.
http://cdsads.u-strasbg.fr/cgi-bin/n...pJ...582.1011S
http://fr.arxiv.org/PS_cache/astro-p...06/0206318.pdf

Lepine, S., Shara, M., Rich, R. Aug. 2003. New High Proper Motion
Stars from the Digitized Sky Survey. II. Northern Stars with 0.5" yr-1
mu 2.0" yr-1 at High Galactic Latitudes. AJ 126(2):921.
http://cdsads.u-strasbg.fr/cgi-bin/n...J....126..921L
http://fr.arxiv.org/PS_cache/astro-p...06/0306534.pdf

Bakos, G., Sahu, K., Nemeth, P. 2002. Revised Coordinates and Proper
Motions of the Stars in the Luyten Half-Second Catalogue. Astrophys.
J. Suppl. Ser. 141, 187
http://cdsads.u-strasbg.fr/cgi-bin/n...pJS..141..187B
http://fr.arxiv.org/PS_cache/astro-p...02/0202164.pdf

Luyten, W.J. 1988. Proper Motions from Carte DU Ciel Plates. IAUS
Symp. No. 133:301
http://cdsads.u-strasbg.fr/cgi-bin/n...AUS..133..301L

Luyten, W.J. 1980. Proper motion survey with the forty-eight inch
Schmidt telescope. LV. First supplement to the NLTT Catalogue. Univ.
Minnesota, Minneapolis.
http://cdsads.u-strasbg.fr/cgi-bin/n...P.....55....1L

Luyten, W.J. 1955. A catalogue of 1849 stars with proper motions
exceeding 0.5" annually. Minneapolis, Lund Press, 1955.
http://cdsads.u-strasbg.fr/cgi-bin/n...ode=1955QB6.L8

Luyten, W.J. 1954. A list of stars with proper motions exceeding 0'5
annually. AJ 59:432.
http://cdsads.u-strasbg.fr/cgi-bin/n...J.....59..432L

van Maanen, Adriaan. July 1938. Investigations in Proper Motions.
Astrophysical Journal. 88:27
http://cdsads.u-strasbg.fr/cgi-bin/n...pJ....88...27V

Jao, W.C. Dec. 2003. Something about the Highest Proper Motion Stars.
American Astronomical Society Meeting 203, #60.03.
http://cdsads.u-strasbg.fr/cgi-bin/n...AS...203.6003J

(Canopus) wrote in message . com...
(justbeats) wrote in message om...
snip
If I find a star in one of my images that's moved a lot from its
position on an earlier DSS plate, then how do I find its "known"
proper motion to compare against my results?

I forgot to mention that you might also want to run your suspect star
through the two main double star catalogues to rule out that you have
a "fast" orbiting member of a binary or multiple star system:

CCDM Catalog of Components of Double & Multiple stars (Dommanget 2002)
http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/274
http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/274

The Washington Visual Double Star Catalog, 1996.0 (Worley 1996)
http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=I/237
http://cdsweb.u-strasbg.fr/viz-bin/Cat?I/237

Enjoy - Canopus

P.S. -

For beginner lurkers, a misc link to another web
high proper motion simulator:

David Nash's 3D Universe -
"Travels through time" java proper motion simulator
http://www.astronexus.com/3duniv/anim.php

(Canopus) wrote in message . com...

[a whole bunch of really useful information]


Canopus

Wow! What a comprehensive and detailed response. You've answered every
one of my general questions and given me scads of interesting info to
follow up...

I'd have never found all this unaided. Thanks for your really helpful
post and the effort you put into creating it. Much appreciated.

Cheers
Beats