Melchiors HD205021B is incorrect - do not use

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Robin Leadbeater
Posts: 1945
Joined: Mon Sep 26, 2011 4:41 pm
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Melchiors HD205021B is incorrect - do not use

Post by Robin Leadbeater »

The spectrum of HD205021B (BD+69 1173B/bet Cep B) in the Melchiors library is not correct. It is either of the wrong star or is heavily contaminated by bet Cep, 13 arcsec away. (It also shows data reduction ripple artifacts)
https://set-p-stweb.bm.icts.kuleuven.be ... 91173B.png
Attached is a comparison with my measurement (ALPY600) my spectrum matches the A1V classification in SIMBAD etc but the spectrum in Melchiors is clearly of a significantly hotter (early B ?) star.
hd205021b_THO_Melchiors_annot.png
hd205021b_THO_Melchiors_annot.png (36.15 KiB) Viewed 475 times
I have been in contact with Dr Pierre Royer who plans to remove it from the Melchiors database and possibly remeasure it at some future date. If you have a downloaded version of the database, I recommend deleting the spectrum of HD205021B
Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Robin Leadbeater
Posts: 1945
Joined: Mon Sep 26, 2011 4:41 pm
Contact:

Re: Melchiors HD205021B is incorrect - do not use

Post by Robin Leadbeater »

HD180482 (22 Aql) is another suspect spectrum in the Melchiors database

melchiorshd180482_THO_Pickles.png
melchiorshd180482_THO_Pickles.png (60.58 KiB) Viewed 183 times

Black is the spectrum in Melchiors,
Blue is the expected spectrum based on the spectral classification and IS extinction
Red is my measurement using a mean of 3 different reference stars (2x Miles stars and a low extinction star with Pickles, all of which gave the same result)

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
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