Königstuhl 1

Königstuhl 1

The red stars are the components of the Königstuhl 1 binary
Observation data
Epoch J2000      Equinox J2000
Constellation Phoenix
LEHPM 494
Right ascension 00h 21m 10.74s
Declination −42° 45′ 40.2″
DENIS-P J0021.0-4244
Right ascension 00h 21m 05.92s
Declination −42° 44′ 43.5″
Characteristics
Evolutionary stage red dwarf
Spectral type M6+M9.5[1]
Astrometry
LEHPM 494
Proper motion (μ) RA: 255.184 ±0.031 mas/yr[2]
Dec.: -12.475 ±0.039 mas/yr[2]
Parallax (π)37.3319 ± 0.0378 mas[2]
Distance87.37 ± 0.09 ly
(26.79 ± 0.03 pc)
DENIS-P J0021.0-4244
Proper motion (μ) RA: 257.820 ±0.374 mas/yr[3]
Dec.: -0.028 ±0.391 mas/yr[3]
Parallax (π)37.9335 ± 0.4038 mas[3]
Distance86.0 ± 0.9 ly
(26.4 ± 0.3 pc)
Details[1]
LEHPM 494
Mass0.103 ±0.006 M☉
Temperature2850 ±100 K
DENIS-P J0021.0-4244
Mass0.079 ±0.004 M☉
Temperature2250 ±100 K
Rotational velocity (v sin i)17.5 ±2.5 km/s
Position (relative to LEHPM 494)[4]
ComponentDENIS-P J0021.0-4244
Angular distance77.78″
Position angle317.0°
Projected separation2083.4 AU
Other designations
WDS J00212-4246
LEHPM 494: 2MASS J00211072-4245401, WISEA J002110.98-424540.3, TIC 7150628
DENIS-P J0021.0-4244: 2MASS J00210589-4244433, 2MUCD 20018, USNO-B1.0 0472-00004560, WISEA J002106.15-424443.4
Database references
SIMBADdata

Königstuhl 1 (KO-1, Kö 1, Koenigstuhl 1) is a binary consisting out of the red dwarf LEHPM 494 and the M- or L-type star or brown dwarf DENIS-P J0021.0-4244. While similar low-mass wide binary were known in young star-forming regions, Königstuhl1 was the first wide binary detected in the field and was not associated with a star-forming region.[1]

Name and discovery

The individual components were known since 1998 (DENIS survey)[5] and 2003 (LEHPM survey),[6] but the binary status was not noticed until José A. Caballero studied them in 2007 and discovered that they move in the same direction. This similar motion was first revealed in the USNO-B1/NOMAD1 proper motion surveys. Caballero also collected 22 years of data to show that the proper motion is consistent. He named the pair Königstuhl 1 because he worked at the Max Planck Institute for Astronomy, which is located on top of the Königstuhl.[1] Other low-mass binaries were discovered by Caballero in the Koenigstuhl survey and called Koenigstuhl 1, Koenigstuhl 2 (Kö 2, Kö 3).[7] The last addition was Koenigstuhl 7 in 2014.[8]

The binary

In the discovery paper Caballero reports a spectral type of M6V for the primary Kö 1A and a mass of around 10% of the sun.[1]

The spectral type of the secondary Kö 1B was first estimated to be >M9V and later the optical spectral type was determined to be M9.5V.[9] Caballero determined a mass of 79 to 87 MJ for the secondary. The binary components are separated by around 1800 astronomical units. This wide orbit also meant that the gravitational binding energy is very low for the binary. At this time one theory existed that explained the presence of low-mass stars and brown dwarfs with the fragmentation and ejection of stellar embryos from molecular clouds. The presence of wide binaries in the field are hard to explain by such a scenario.[1]

The infrared spectral type of Kö 1B was determined to be L0.6: in 2014.[10] The gravity on this object is consistent with other old field dwarfs.[11] Later it was determined that Kö 1 could be part of the 200 Myr old Carina Near Association.[12] If this is true, Kö 1B would be less massive and it would have a mass of 51.88±3.6 MJ.[13] A more precise separation of 2083.4 AU was reported in 2021 and Kö 1B might have two components.[4]

See also

Other low-mass wide binaries:

References

  1. ^ a b c d e f Caballero, J. A. (2007-02-01). "The widest ultracool binary". Astronomy and Astrophysics. 462 (3): L61–L64. arXiv:astro-ph/0612234. Bibcode:2007A&A...462L..61C. doi:10.1051/0004-6361:20066814. ISSN 0004-6361.
  2. ^ a b Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. ^ a b Cifuentes, Carlos; Caballero, José A.; Agustí, Sergio (2021-06-01). "One Is the Loneliest Number: Multiplicity in Cool Dwarfs". Research Notes of the American Astronomical Society. 5 (5): 129. arXiv:2106.05049. Bibcode:2021RNAAS...5..129C. doi:10.3847/2515-5172/ac05ce. ISSN 2515-5172.
  5. ^ Tinney, C. G.; Delfosse, X.; Forveille, T.; Allard, F. (1998-10-01). "Optical spectroscopy of DENIS mini-survey brown dwarf candidates". Astronomy and Astrophysics. 338: 1066–1072. arXiv:astro-ph/9805311. Bibcode:1998A&A...338.1066T. ISSN 0004-6361.
  6. ^ Pokorny, R. S.; Jones, H. R. A.; Hambly, N. C. (2003-01-01). "The Liverpool-Edinburgh high proper motion survey". Astronomy and Astrophysics. 397 (2): 575–584. arXiv:astro-ph/0209557. Bibcode:2003A&A...397..575P. doi:10.1051/0004-6361:20021385. ISSN 0004-6361.
  7. ^ Caballero, José Antonio (2007-09-01). "Southern Very Low Mass Stars and Brown Dwarfs in Wide Binary and Multiple Systems". The Astrophysical Journal. 667: 520–526. arXiv:0706.1346. Bibcode:2007ApJ...667..520C. doi:10.1086/520873. ISSN 0004-637X.
  8. ^ Aberasturi, M.; Caballero, J. A.; Montesinos, B.; Gálvez-Ortiz, M. C.; Solano, E.; Martín, E. L. (2014-08-01). "Search for Bright Nearby M Dwarfs with Virtual Observatory Tools". The Astronomical Journal. 148 (2): 36. arXiv:1408.1611. Bibcode:2014AJ....148...36A. doi:10.1088/0004-6256/148/2/36. ISSN 0004-6256.
  9. ^ Basri, Gibor (2000-01-01). "Observations of Brown Dwarfs". Annual Review of Astronomy and Astrophysics. 38: 485–519. Bibcode:2000ARA&A..38..485B. doi:10.1146/annurev.astro.38.1.485. ISSN 0066-4146.
  10. ^ Bardalez Gagliuffi, Daniella C.; Burgasser, Adam J.; Gelino, Christopher R.; Looper, Dagny L.; Nicholls, Christine P.; Schmidt, Sarah J.; Cruz, Kelle; West, Andrew A.; Gizis, John E.; Metchev, Stanimir (2014-10-01). "SpeX Spectroscopy of Unresolved Very Low Mass Binaries. II. Identification of 14 Candidate Binaries with Late-M/Early-L and T Dwarf Components". The Astrophysical Journal. 794 (2): 143. arXiv:1408.3089. Bibcode:2014ApJ...794..143B. doi:10.1088/0004-637X/794/2/143. ISSN 0004-637X.
  11. ^ Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle L.; Lafreniére, David; Doyon, René; Malo, Lison; Burgasser, Adam J.; Naud, Marie-Eve; Artigau, Étienne; Bouchard, Sandie; Gizis, John E.; Albert, Loïc (2015-08-01). "BANYAN. VII. A New Population of Young Substellar Candidate Members of Nearby Moving Groups from the BASS Survey". The Astrophysical Journal Supplement Series. 219 (2): 33. arXiv:1506.07712. Bibcode:2015ApJS..219...33G. doi:10.1088/0067-0049/219/2/33. ISSN 0067-0049.
  12. ^ Gagné, Jonathan; Faherty, Jacqueline K. (2018-08-01). "BANYAN. XIII. A First Look at Nearby Young Associations with Gaia Data Release 2". The Astrophysical Journal. 862 (2): 138. arXiv:1805.11715. Bibcode:2018ApJ...862..138G. doi:10.3847/1538-4357/aaca2e. ISSN 0004-637X.
  13. ^ Sanghi, Aniket; Liu, Michael C.; Best, William M. J.; Dupuy, Trent J.; Siverd, Robert J.; Zhang, Zhoujian; Hurt, Spencer A.; Magnier, Eugene A.; Aller, Kimberly M.; Deacon, Niall R. (2023-11-08). "Table of Ultracool Fundamental Properties". Zenodo. doi:10.5281/zenodo.10086810.