The Star Mass Project

(c) 2022 by Barton Paul Levenson



Updates


2022

02/28/2022. Recently acquired eight (8) more stars from four (4) references, all of the latter from the 2022 literature. Redid analysis. Updated tables, graphs, and web pages today. New total: 497 stars, with a mean relative absolute deviation (MRAD) of 0.148 (i.e., almost 15%). I sincerely hope these are all main sequence, and I hope someone will inform me of any that are not. When DEBCAT tells me a type K4.5V star (V1174 Orionis A) has a mass of 1.009 Solar masses with a probable error of only 0.015, I strongly suspect that that star is not on the main sequence. That, or the analysis in the original paper was off, or else here's something new we didn't previously know about stellar astronomy.

03/03/2022. Acquired 17 new stars and updates on KX Cancri A and B, including new spectral types for each. Lots of new F stars. This is from the 2021 literature on detached eclipsing binaries. Soon I'll retrace 2022 and 2021 for visual binary studies. New total: 514 stars, MRAD has decreased slightly to 0.147.

Later: Acquired 47 more stars from a mere three sources on visual and astrometric/spectroscopic binaries in 2022 (I did not use m sin i figures; absolute masses only, and I left out any possible dubious cases). Now I have 561 stars in the database. MRAD = 0.145.

03/07/2022. Acquired 31 new stars and updates on α Centauri A and B, from visual, astrometric, and speckle interferometric studies in 2021 and 2022. Stars in the database: 592. MRAD = 0.143.

Later: Acquired 23 more stars (detached eclipsing binary components) from 2020 sources. N = 615, MRAD = 0.142.

03/09/2022. Acquired 32 more stars from 2020 sources. N = 646, MRAD = 0.145. This is the first time the mean probable error has increased by adding more stars. They must have larger probable errors than the previous collection.

03/10/2022. Acquired 18 more stars from 2020 sources and closed out the literature search for 2020. N = 662, MRAD = 0.144. I also removed the system V453 Cygni from the list, as I found a source which said both components are subgiants (luminosity class IV). I don't know how far this kind of mistake has contaminated my database, but I will keep an eye out.

03/12/2022. Acquired 29 new stars from 2019 sources. N = 689, MRAD = 0.143. I removed a system (can't remember the name) which turned out to be pre-main-sequence. Also got revised information for χ2 Hydrae.

03/13/2022. Acquired 25 new stars from 2019 sources and one 2001 source which Google Scholar misfiled under 2019. N = 714, MRAD = 0.143.

03/16/2022. Acquired 45 new stars from 2018 sources, including a lot of new type-M red dwarfs. I'm especially interested in type O and type M, the two ends of the main-sequence spectrum, since there seem to be very few validated masses for either (at least, with spectral type also given). I've found no masses for early type L at all, though types L0 through L2 are probably also stars, whereas L3 on are below the lower mass limit for stars (0.075 M), and must be considered brown dwarfs. N = 759, MRAD = 0.144. :(

Later: I removed ζ Phoenicis A from the database, as Wikipedia says A by itself is an Algol binary. Haven't recalculated yet, although one star out of 759 shouldn't make much of a difference.

03/19/2022. Acquired 47 new stars from 2018 and 2017 sources. Had to remove 3 for being off the main sequence (e.g. Beta Aurigae). After calculating and posting, I noticed I had one star twice--hope there aren't many such cases. Anyone who can identify a problem, please contact me. N = 801, MRAD = 0.148 (it just keeps getting worse).

03/22/2022. Got rid of some more non-main sequence stars, and acquired 20 new ones, including, for the first time, five stars of spectral class L (three L0 and two L1.5). Thanks to a wonderful 2017 paper by Dupuy and Liu for the small-star data. I also dropped the loess smooth I'd been hoping would help me build my table; see the Results page for details. N = 819.

03/25/2022. A few more stars dropped, some after this analysis was done--I always spot a few mistakes after doing the analysis and putting it into the web site. *sigh* I'm happy that I now have five type L stars on the list, three L0V and two L1.5V. N = 848 (actually 845 since I had to remove a few).

03/27/2022. Several more stars dropped, mostly as pre-main sequence. I found one really strange source (Ka15 in the reference list) which found pretty precise masses for four stars which it stated were on the main sequence according to their HR diagram placement. But according to the effective temperatures they listed, the spectral types appeared to show three F8V stars with about 0.8 Solar masses each and a G2V with even less. They were in a globular cluster, so I suppose this could be some weird metallicity problem, but I'm guessing they have a systematic error based on the fact that it's so far to even the closest globular clusters. Nonetheless, I couldn't take out four data points just on the basis that I had some suspicions about them, so in they went. N = 867.

03/29/2022. Added 40 more stars, including four more weirdly undersized ones from a globular cluster. Working backwards from 2022, I have now gone through all the literature in Google Scholar for "detached eclipsing" and "component masses" -"black hole" through 2012. N = 903 from 11 years of the professional literature.

04/08/2022. Added 43 more stars and updated figures for 70 Ophiuchi, advancing the literature search back through 2010. I had a lot of trouble with duplicates for a while--once ten at once--which I invariably noticed after I had done the math and revised the web pages (though thank God I didn't get as far as posting them). N = 946.

04/11/2022. Added 38 new stars and updated figures for 12 Persei and δ Equulei (I was depending on Popper 1980 for both; now I have figures from 28 years later). One new system is in the Andromeda Galaxy! Literature search complete from 2022 back through 2008 so far. N = 984.

04/14/2022. I did something I should have done from the start--I added secondary designations to pin down which star is meant in the Raw Data table. This enabled me to remove no fewer than 29 erroneous data points, some of which were stars of the wrong type, but most of which were duplicates. I also revised the tables to look a little more readable. N = 955.

04/17/2022. More stars, though I caught 2 duplicates only after I did the analysis. N = 993 (991).

04/19/2022. Just 16 new stars, from all the literature I could find for 2001-2003. One pre-main sequence system removed (HD 98800). N = 1,006.

04/22/2022. A few new stars. It's getting very hard to find figures as I go back through the literature; fewer and fewer orbital studies were done as far back as 1993--at least ones that were not later superceded. I'm putting the project on hold because I think I've effectively run out of data--there just aren't that many mass figures for main sequence stars in the literature. N = 1,029 as I temporarily bring the project to a close. To get a smooth progression I think I would need at least 4,000 stars, and the data just aren't there.




Page created:02/28/2022
Last modified:  04/22/2025
Author:BPL