HIGH PROPER MOTION STARS - VARIABLE NEBULA (below)
Some stars move comparatively
quickly across the sky and are said to have a high proper motion.
This concept was first noticed by Edmund Halley in 1718, comparing
positions of several stars with those recorded 2000 years beforehand.
The first modern high proper motion star identified was 61 Cygni,
discovered by G.Piazzi in 1792.
Typically, they are very close to our Solar System and some also have a
high intrinsic speed relative to stars around them.
Over several years I've followed these three: Barnard's Star, Kapteyn's Star and Proxima Centauri.
Barnard's Star in Ophiuchus
Discovered in 1916 by
E.E.Barnard. It has the highest known proper motion of any star visible
from Earth.
Type: M4v red dwarf. Magnitude: 9.5. Distance: 5.99 light years. Proper
Motion: 10.29 arc sec/yr in PA 356.
Coordinates (2010): RA 17h 57m 48.04s Dec +04d 43m 25.2s
Stellarium
chart extract showing position of Barnard's Star
Image taken on 6 June 2015 with
8cm f5 refractor, FOV 55' x 42'. Barnard's Star arrowed.
Over the 35 years I have recorded Barnard's Star, it has moved 360.15 arc sec (just over 6 arc mins).
Kapteyn's Star in Pictor
Discovered in 1897 by Prof. J.C.Kapteyn. It is the 2nd highest proper motion star in the sky after Barnard's Star.
Type: M0 red dwarf. Magnitude:
8.8 Distance: 12.7 light years. Proper Motion: 8.7 arc sec/yr in PA 131.
Coordinates (2009): RA 05h 11m 46.8s Dec -45d 02m 01.5s
Animation showing the movement from 2006 to 2009. I have been lucky to image Kapteyn's star on exactly the same date 3 years running. Due to cloudy weather, I missed the 2009 date but got it a couple of weeks later on 20091016.
Left image is 55 minutes wide. Taken through a 300mm lens and GSTAR-EX video camera.
Proxima Centauri
Discovered by R.T.Innes in 1915. Proxima Centauri is the closest known star to our solar system.
Type: dM5e red dwarf. Magnitude:
10.7 (flare star) Distance: 4.244 light years. Proper Motion: 3.85 arc
sec/yr in PA 282.
Coordinates 01 Jan 2020: RA 14 29 31.962 Dec - 62 40 30.77
Stellarium
chart extract showing Proxima in relation to Alpha and Beta
Centauri.
Over the 35 years I have recorded Proxima, it has moved 134.75 arc seconds (2 min 14 secs).
* The New Horizons
Parallax Program *
A rare opportunity for amateur
astronomers.
On the 22 April 2020 I image both Proxima Centauri and Wolf 359 in Leo
at the same time as the New Horizons (NH) spacecraft. By making
simultaneous observations, it negates the need to compensate for other
factors such as the proper motion of the stars. Previously all distance
measurements to nearby stars were made using the Earths distance from
the Sun (150 million kilometres) as the baseline , known as an
Astronomical Unit (AU). The very slight shift of the nearby star seen
against the more distant stars viewed from either side of the Earths
orbit (6 months apart), is known as Stellar Parallax. Even the closest
star, Proxima, has a shift less than the width of a typical stars image
spot (smaller than 1 arc second). Because the New Horizons spacecraft
was so far from Earth at the time of these images, 46.8 AU (over 7
billion kilometres), it gave a much wider baseline and parallax shift
which could be easily recorded and measured by amateur astronomers.
My friend John Sarkissian OAM (CSIRO Parkes Radio Observatory) measured these images and calculated the distance to Proxima and Wolf 359. He included corrections for the range to the spacecraft and the angles from the two stars, he arrived at values that agree extremely well with modern measurements.
LHS 2085
I happened upon this one accidentally while imaging the nebula RCW 38 in Vela.
When blending the colour print
taken in 1989 with the 2007 image,
I noticed a star at the centre of field had moved significantly during
the 18 years between images.
Thank you to Rob McNaught for finding the ID of this star and supplying
the following info:
Discovered by Willem Jacob
Luyten. In his 1979 Proper Motion Catalogue:
Type: M1.5 D. Magnitude: 12.8R, 14.3B. Tycho gives mag 11.8V. Distance:
?. Proper Motion: 0.70 arc sec/yr in PA 327.94.
Coordinates (2014): RA 09h 00m 02s Dec -47d 29m 57s
Note: a lot more stars appear in the later shot due to the much more sensitive camera, especially on the red end of the spectrum.
NGC 6729 in Corona Australis
ID image on 2011 Nov 06 with 20
cm f/4 Newtonian Reflector and GSTAR-EX video camera no filter 400 video
frames (luminance channel)
NGC 2261 in Monoceros
Imaged on 20061128 with 31.5 cm f/4.5 Newtonian Reflector and GSTAR-EX video camera 200 video frames no filter
Reflection nebula known as Hubble's variable nebula. Changes in brightness are caused by the variable star R Monocerotis.
Animation shows changes from Nov 2006 to Jan 2014
The
Crab Nebula in Taurus. (Messier 1, NGC 1952)
At the suggestion of Steve Massey, I imaged the Crab on Jan 16th 2018 and compared it to my image from 2006.
To my amazement it did show some changes in the nebula and filaments.
The images also shows a magnitude 8.3 star with high proper motion in the upper right - HIP 26240 aka G 100 - 20, moving about 0.25"/yr.
