31 august 2022, close pairs

Had a pretty good session last night with the 20-inch.  Seeing was predicted to be excellent, but it started out a little choppy so I started out with some Struves.  After a while a couple of those were very close, so I switched over to the physical star list.

STT 344 AB: 508; 145x: White A and light red B, 3Dm, well separated.  WDS calls this a physical double, but there is no overlap of the parallax ranges, -46%, it is not binary.

18h 07m 06.29s +49° 42' 37.6" P.A. 140.00 sep 2.3 mag 6.47,10.31 Sp A2V dist. 221.24 pc (721.68 l.y.)

STF2282 AB: 508; 145x: White stars, 1 Dm, well separated.  BC is a 0.2" pair, not looked for, need to reobserve.  WDS uncertain, and there is no parallax data for the primary.

18h 06m 30.47s +40° 21' 39.6" P.A. 83.00 sep 2.7 mag 7.93,9.43 Sp A1V dist. 512.82 pc (1672.82 l.y.)

STF2290 AB: 508; 145x: 2 Dm, B seen with averted vision then can hold direct, well separated around 4".  WDS uncertain, and there is no parallax data for the primary. 

18h 06m 37.28s +50° 00' 38.3" P.A. 351.00 sep 4.0 mag 9.23,11.20 Sp A5 dist. 684.93 pc (2234.24 l.y.)

STF2270 AB: 508; 145x: Faint for a Struve pair, slight delta magnitude, wide.  WDS uncertain, but there is 67% parallax range overlap, 1,666 AU weighted separation, 1.3+1.2 Msol, and the radial velocity delta 0.3 is less than the escape velocity 1.7, so it is very likely binary and needs an orbit calculated.

18h 01m 27.46s +45° 17' 50.5" P.A. 212.00 sep 6.3 mag 10.95,11.10

STF2267 AB: 508; 600x: Slight delta magnitude, detected at 300x but have a nice well split at 600x.  WDS grade 4 1660-year orbit, but unfortunately there is no Gaia parallax for the primary.  It is nearing periastron but not likely to make significant change in the next 20 years.

18h 01m 41.17s +40° 10' 41.9" P.A. 278.50 sep 0.5 mag 8.41,8.84 Sp A3 dist. 249.38 pc (813.48 l.y.)

STF2275 AB: 508; 600x: Hairline split, unequal.  Nice!  WDS grade 4 orbit, 525-year period, at secondary apistron but will not make significant change the next 20 years.  No Gaia parallax available.

18h 03m 17.38s +39° 20' 58.5" P.A. 307.40 sep 0.3 mag 10.11,10.16 Sp G0 dist. 123.92 pc (404.23 l.y.)

STF2293 AB: 508; 145: Clean white A and dull wide B, 3 Dm.  WDS says parallax indicates physical, but there is no overlap of the parallax ranges, -32%, it is not binary.

18h 09m 53.83s +48° 24' 05.7" P.A. 83.00 sep 13.0 mag 8.08,10.34 Sp G0 dist. 78.99 pc (257.67 l.y.)

STF2298 AB: 508; 145x: Very pretty white A and nearly 2 Dm, 2" separated B.  WDS uncertain, but there is no overlap of the parallax ranges, -51%, it is not binary.

18h 12m 38.87s +41° 23' 08.1" P.A. 172.00 sep 1.9 mag 8.76,9.94 Sp F5 dist. 120.92 pc (394.44 l.y.)

STF2295 AB: 508; 145x: Light yellow-orange A and 3 Dm B, wide.  WDS says it is not physical, and there is no overlap of the parallax ranges, -97%, it is certainly not binary.

18h 12m 34.10s +31° 34' 47.2" P.A. 173.00 sep 8.3 mag 8.59,10.92 Sp M0 dist. 714.29 pc (2330.01 l.y.)

STT 343 AB: 508; 200s: White A and 3 Dm B, well split.  WDS uncertain, but there is 35% overlap of the parallax ranges, only 388 AU weighted separation, 1.9+1.0 Msol, and the radial velocity delta 2.1 is less than the escape velocity 3.6, so it is likely binary and someone should run an orbit.

18h 04m 56.93s +48° 08' 09.8" P.A. 79.00 sep 3.3 mag 7.63,10.51 Sp A7V dist. 126.9 pc (413.95 l.y.)

HU674 AB: 508; 530x: 1 Dm, white, cleanly and well split.  WDS grade 4 orbit, 773-year period, it will make a rapid periastron by 2050, certainly one to watch in the coming years as it will become more difficult to split and move due south.  But incredibly Gaia DR3 shows there is no parallax range overlap, by -47%, so these may not be binary at all, and the "orbit" just an effect of their relative motions.

18h 09m 40.64s +50° 24' 07.4" P.A. 211.90 sep 0.7 mag 7.68,8.63 Sp A3V dist. 141.04 pc (460.07 l.y.)

BU 1127 AB: 508; 600x: Light yellow A and blue B, needed high magnification the bright primary far enough apart from the 2 Dm B.  WDS says physcial but that a premature orbit is calculated.  No Gaia data for the seconary. 

18h 02m 30.89s +44° 14' 02.6" P.A. 39.00 sep 0.7 mag 7.31,9.20 Sp F5V dist. 81.3 pc (265.2 l.y.)

HU 1185 AB: 508; 600x: Very delicate hairline split, light orange stars, 1 Dm, quite nice.  WDS grade 5 orbit 240-year period.  No Gaia parallax data for the primary.  It will make very little change in the next 20 years.

17h 59m 04.61s +32° 28' 26.3" P.A. 147.20 sep 0.4 mag 9.81,10.48 Sp G0 dist. 134.05 pc (437.27 l.y.)

HU 1291 AB: 508; 900x: Mostly see a notched snowman of unequal stars, but it does momentarily resolve to a hairline split with seeing.  WDS grade 4 orbit 216-year period, and no Gaia parallax data for the stars.  Assuming the orbit is correct, it will widen and turn more northerly in the next 20 years.

18h 16m 16.75s +36° 25' 18.1" P.A. 43.70 sep 0.3 mag 9.30,10.00 Sp F5

A 253 AB: 508; 600x: Gorgeous, perfect star images, light orange stars, slight magnitude difference, nicely split.  WDS grade 4 orbit, 98.57-year period, but amazingly there is no overlap of the parallax ranges, -22%, so in spite of the mere 46 AU weighted separation, 0.8+0.7 Msol, it might turn out this is not binary at all.  If the orbit is correct, it will tighten to indetectibility by 2035.  It could just be a line of sight pair.

18h 43m 43.55s +31° 40' 54.1" P.A. 140.20 sep 0.5 mag 9.71,10.29 Sp K0 dist. 47.62 pc (155.34 l.y.)