HD 72945 and HD 72946
Binary star system in the constellation of Cancer
HD 72945 & HD 72946
Observation dataEpoch J2000.0 Equinox J2000.0
Constellation
Cancer
HD 72945
Right ascension
08h 35m 50.978s [1]
Declination
06° 37′ 12.77″[1]
Apparent magnitude (V)
5.91[2]
HD 72946
Right ascension
08h 35m 51.267s [3]
Declination
06° 37′ 21.95″[3]
Apparent magnitude (V)
7.25[2]
Characteristics
HD 72945
Evolutionary stage
Main sequence[4]
Spectral type
F8 V[5]
B−V color index
0.530± 0.007[2]
HD 72946
Spectral type
G5V[6]
B−V color index
0.710± 0.015[2]
Astrometry HD 72945 Radial velocity (Rv )26.61± 0.15[7] km/s Proper motion (μ) RA: −130.308 mas /yr [1] Dec.: −133.119 mas /yr [1] Parallax (π)38.4212 ± 0.1515 mas [1] Distance 84.9 ± 0.3 ly (26.0 ± 0.1 pc ) Absolute magnitude (MV )3.91[2] HD 72946 Radial velocity (Rv )28.75± 0.14[8] km/s Proper motion (μ) RA: −136.593 mas /yr [3] Dec.: −137.148 mas /yr [3] Parallax (π)38.9809 ± 0.0412 mas [3] Distance 83.67 ± 0.09 ly (25.65 ± 0.03 pc ) Absolute magnitude (MV )5.16[2]
Orbit [7] Primary HD 72945 A Period (P) 14.2995± 0.0001 dSemi-major axis (a)≥4.07 ± 0.05 Gm (5.850 ± 0.072 R ☉ ) Eccentricity (e)0.332± 0.008 Periastron epoch (T) 2,446,781.30± 0.12 JD Argument of periastron (ω) (secondary)227.1± 3.0° Semi-amplitude (K1 ) (primary)21.95± 0.15 km/s
Details HD 72945 Mass 1.245± 0.030[9] M ☉ Radius 1.358[10] R ☉ Luminosity 2.372[10] L ☉ Surface gravity (log g )4.32[11] cgs Temperature 6,222[11] K Metallicity [Fe/H]0.05[11] dex Rotational velocity (v sin i )7.1[11] km/s Age 1.584± 0.952[9] Gyr HD 72946 Mass 1.02± 0.04[12] M ☉ Radius 0.97± 0.02[12] R ☉ Luminosity 0.84[2] L ☉ Surface gravity (log g )4.69[13] cgs Temperature 5,670[12] K Metallicity [Fe/H]0.16[12] dex Rotational velocity (v sin i )4.14[9] km/s Age 1.9+0.6 −0.5 [6] Gyr
Other designations HD 72945 : Boss 2285[16] , GC 11781, HIP 42172, HR 3395, SAO 116929, PPM 154707, NLTT 19856[14] HD 72946 : Boss 2286[16] , GC 16412, HIP 42173, HR 3396, SAO 116931, PPM 154708, NLTT 19851[15]
Database references SIMBAD HD 72945 HD 72946
HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer .[17] HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91.[2] At an angular separation of 10.10″ (as of 2020)[18] is the fainter companion star HD 72946 at magnitude 7.25.[2] It is being orbited by a brown dwarf .[9] The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.[1] [3]
The discovery of this double star was announced by F. G. W. Struve in 1782, and later given the discovery code STF 1245.[18] Their common proper motion was confirmed by A. van Maanen in 1916, and this suggested they are physically associated.[16] The projected separation of the two systems is 258.9 AU .[19] Based on astrometric measurements from the Gaia spacecraft , the semimajor axis of this system is 200+52 −41 AU .[6] Assuming they are gravitationally bound , they would have an orbital period of around 2,500 years.[20]
There is an additional candidate stellar companion at an angular separation of ~130″ , which would make this a four star system. (This object has the 2MASS designation J08354678+0635294.)[9] Three additional faint companions detected by Struve are most likely background stars.[7]
HD 72945
The binary nature of HD 72945 was announced in 1919 by A. H. Joy and G. Abetti at the Mount Wilson Observatory . Observed variations in the radial velocity of the primary component inferred an orbiting stellar companion.[16] This is a single-lined spectroscopic binary system with a period of 14.3 days and an orbital eccentricity of 0.33.[7] The minimum value for the semimajor axis is only 5.9 times the radius of the Sun , although the actual value is uncertain because the orbital inclination is unknown.[7]
The visible component of this system has a stellar classification of F8 V,[5] matching an ordinary F-type main-sequence star . It has 1.25[9] times the mass of the Sun and 1.4[10] times the Sun's radius . The star is radiating 2.4[10] times the luminosity of the Sun from its photosphere at an effective temperature of 6,222 K.[11] It has an estimated age of approximately 1.6 billion years.[9] The derived minimum mass for the secondary component is 0.34 M ☉ .[9]
HD 72946
This is a G-type main-sequence star with a class of G5V.[6] It has about the same size and mass as the Sun.[12] However, the star is slightly more active than the Sun, and thus probably younger.[6] It is metal-rich , showing a higher abundance of elements other than hydrogen and helium compared to the Sun.[21]
In 2016, a candidate brown dwarf companion in orbit around HD 72946 was announced. It was discovered based on radial velocity monitoring over a twenty-year period.[22] The companion was confirmed in 2020.[9] It has a classification of L5.0± 1.5 , a derived temperature of 1,700± 90 K , and a mass near the hydrogen-burning limit .[6] The orbit lies just outside the ice line of the host star, with a semimajor axis of about 6.5 AU .[9] It is orbiting with a period of 16 years[6] and an eccentricity of 0.498.[23]
References
^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties" . Astronomy & Astrophysics . 649 : A1. arXiv :2012.01533 . Bibcode :2021A&A...649A...1G . doi :10.1051/0004-6361/202039657 . S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source at VizieR .
^ a b c d e f g h i Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters , 38 (5): 331, arXiv :1108.4971 , Bibcode :2012AstL...38..331A , doi :10.1134/S1063773712050015 , S2CID 119257644 .
^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties" . Astronomy & Astrophysics . 649 : A1. arXiv :2012.01533 . Bibcode :2021A&A...649A...1G . doi :10.1051/0004-6361/202039657 . S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source at VizieR .
^
^ a b Abt, Helmut A. (December 23, 2008), "Mk Classifications of Spectroscopic Binaries", The Astrophysical Journal Supplement Series , 180 (1): 117–118, Bibcode :2009ApJS..180..117A , doi :10.1088/0067-0049/180/1/117 , eISSN 1538-4365 , ISSN 0067-0049 .
^ a b c d e f g h Brandt, G. Mirek; et al. (December 2021), "Improved Dynamical Masses for Six Brown Dwarf Companions Using Hipparcos and Gaia EDR3", The Astronomical Journal , 162 (6): 28, arXiv :2109.07525 , Bibcode :2021AJ....162..301B , doi :10.3847/1538-3881/ac273e , S2CID 237532125 , 301.
^ a b c d e Duquennoy, A.; Mayor, M. (1991), "Multiplicity among solar-type stars in the solar neighbourhood. II – Distribution of the orbital elements in an unbiased sample", Astronomy & Astrophysics , 248 (2): 485–524, Bibcode :1991A&A...248..485D .
^ Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties" . Astronomy & Astrophysics . 616 . A1. arXiv :1804.09365 . Bibcode :2018A&A...616A...1G . doi :10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR .
^ a b c d e f g h i j Maire, A. -L.; et al. (January 2020), "A dusty benchmark brown dwarf near the ice line of HD 72946", Astronomy & Astrophysics , 633 : 10, arXiv :1912.02565 , Bibcode :2020A&A...633L...2M , doi :10.1051/0004-6361/201937134 , S2CID 208637214 , L2.
^ a b c d Schofield, Mathew; et al. (2019), "The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite", The Astrophysical Journal Supplement Series , 241 (1): 12, arXiv :1901.10148 , Bibcode :2019ApJS..241...12S , doi :10.3847/1538-4365/ab04f5 , S2CID 119481586 .
^ a b c d e Luck, R. Earle (January 2017), "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants", The Astronomical Journal , 153 (1): 19, arXiv :1611.02897 , Bibcode :2017AJ....153...21L , doi :10.3847/1538-3881/153/1/21 , S2CID 119511744 , 21.
^ a b c d e Hirsch, Lea A.; et al. (2021), "Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc", The Astronomical Journal , 161 (3): 134, arXiv :2012.09190 , Bibcode :2021AJ....161..134H , doi :10.3847/1538-3881/abd639 , S2CID 229297873 .
^ Gray, R. O.; et al. (2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I", The Astronomical Journal , 126 (4): 2048, arXiv :astro-ph/0308182 , Bibcode :2003AJ....126.2048G , doi :10.1086/378365 , S2CID 119417105 .
^ a b "HD 72945" , SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2022-05-31 .
^ a b "HD 72946" , SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2022-05-31 .
^ a b c d Joy, A. H.; Abetti, G. (December 1919), "The orbit of the spectroscopic binary Boss 2285", Astrophysical Journal , 50 : 391–393, Bibcode :1919ApJ....50..391J , doi :10.1086/142515 .
^ Sinnott, Roger W.; Perryman, Michael A. C. (1997), Millennium Star Atlas , vol. 2, Sky Publishing Corporation and the European Space Agency, p. 761, ISBN 0-933346-83-2 .
^ a b Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog" , The Astronomical Journal , 122 (6): 3466–71, Bibcode :2001AJ....122.3466M , doi :10.1086/323920 .
^ Tokovinin, A.; Kiyaeva, O. (February 2016), "Eccentricity distribution of wide binaries", Monthly Notices of the Royal Astronomical Society , 456 (2): 2070−2079, arXiv :1512.00278 , Bibcode :2016MNRAS.456.2070T , doi :10.1093/mnras/stv2825 , S2CID 1615080 .
^ Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal , 147 (4): 87, arXiv :1401.6827 , Bibcode :2014AJ....147...87T , doi :10.1088/0004-6256/147/4/87 , S2CID 56066740 .
^ Feltzing, S.; Gustafsson, B. (April 1998), "Abundances in metal-rich stars. Detailed abundance analysis of 47 G and K dwarf stars with [Me/H] > 0.10 dex", Astronomy and Astrophysics Supplement , 129 : 237–266, arXiv :astro-ph/9710315 , Bibcode :1998A&AS..129..237F , doi :10.1051/aas:1998400 , S2CID 14419843 .
^ Bouchy, F.; et al. (January 2016), "The SOPHIE search for northern extrasolar planets. VIII. Follow-up of ELODIE candidates: long-period brown-dwarf companions", Astronomy & Astrophysics , 585 : 8, arXiv :1511.08397 , Bibcode :2016A&A...585A..46B , doi :10.1051/0004-6361/201526347 , S2CID 55950304 , A46.
^ a b Balmer, W.O.; et al. (2023). "VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B" . The Astrophysical Journal . 956 (2): 24. arXiv :2309.04403 . Bibcode :2023ApJ...956...99B . doi :10.3847/1538-4357/acf761 . 99.