47 Ursa-Major

I was awaiting astrometry for 47 Biggis Dipperae, alias HD 95128 or (in Siamese) Chalawan. The latest Msini constraints are promising: Rosenthal et al., “The California Legacy Survey I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades”, sent to arxiv July 2021. In part.

As for d (1.5+ M_j at 13.8 AU) you’d think it could be directly-imaged were it a brown dwarf even a T dwarf. As for overall stability d is here confirmed eccentric between 0.23 and 0.54, probably how c is (now) out to e=0.18.

Rosenthal’s Appendix B refers to a full Table 2, which is apjsabe23ct2_mrt.txt.

Idx HD        TempK   Terr  Fe/H  FeHEr ln(g) lngErr Rad   RadEr Mass  Merr   Vmag   B-V     DR2‘llax  
506 95128     5829.2  94.8  0.026 0.061 4.328 0.032  1.137 0.027 1.005 0.047  4.3575 0.56    0.07245

I say we can do better. From the Gaia Archive I was able to look up HD 95128 in Basic. That resolved to the following 2000-2016 ADQL query:

SELECT TOP 2000 gaia_source.source_id --never mind the rest
FROM gaiadr3.gaia_source
WHERE
CONTAINS(
              POINT('ICRS',gaiadr3.gaia_source.ra,gaiadr3.gaia_source.dec),
              CIRCLE(
                             'ICRS',
COORD1(EPOCH_PROP_POS(164.86655313,40.43025571,72.0070,-316.8500,55.1800,11.1420,2000,2016.0)),
COORD2(EPOCH_PROP_POS(164.86655313,40.43025571,72.0070,-316.8500,55.1800,11.1420,2000,2016.0)),
                             0.001388888888888889)
)=1

This returns the result and very quickly, too: id 777254360337133312, which I can now use for a SELECT *. I suggest viewing the results in the browser. A download will produce a vot.gz which cannot be “tar -xvzf”’d in Windows 11: “Unrecognized archive format”. I won’t download 7-zip or WinZip on this machine, I am running out of laptops as you know.

DR3 parallax is 72.00696109116399 mas. So 13.9 parsecs away not 13.8. Temperature is dimmer too: 5763.587 K, with only 2 K errorbar either side. Ln(g) is 4.2777 which isn’t much less than the 4.328 in the R’thal DR2-based table: I suppose because to be as bright as it is, the radius is more than was thought. I believe I have netted the right object.

In search of d, a circle at 0.02 offers id 777254562202782848 as the closest object in our field-of-vision. That’s 1455 parsecs away so an obvious background spot. d did not get found in DR3.

As to astrometry I am told that the smart people can cross-check this to Hipparchos: How to write ADQL queries for Gaia data - Gaia Users - Cosmos (esa.int) If you’re smart, not dumb like people say, and you want respect.

This 47 UMa system is Solar mass albeit bigger (so older). Its jovians are large and distant. Never mind the Hill Sphere; Kirkwood should impose mass-constraints upon b (2.438+ M_j at 2.059 AU) and c (0.5+ @3.4) at least. Their periods and masses resemble Jupiter:Saturn 5:2 but, like, more so.

As to luminosity DR2 R was 1.137; DR3 T at 5761-5 K is (barely!) subsolar, such that T⁴= 0.995. But I think R is higher than DR2’s result. L=1.137*1.137 which I’ll round up: 1.3. Wikipedia had pre-DR2 priors so different (higher) L.