Blanco 1

Blanco 1
Observation data (J2000 epoch)
Right ascension	00^h 04^m 24^s[1]
Declination	–29° 56.4′[1]
Distance	850+160 −130 ly (260+50 −40 pc)[1]
Physical characteristics
Estimated age	100–150[1] Myr
Associations
Constellation	Sculptor

Blanco 1 (ζ Sculptoris cluster) is a nearby open cluster of stars located around 850 light years away from the Sun in the southern constellation of Sculptor near the star ζ Sculptoris. It was discovered by Puerto Rican astronomer Víctor Manuel Blanco in 1959,^[1] who noticed an unusually high proportion of A-type stars in an area spanning 1.5°.^[2] This cluster is relatively young, with an age of about 100–150 million years. It is positioned at a high galactic latitude of b = –79.3° and is located some 780 ly (240 pc) below the galactic plane.

Blanco 1 contains approximately 300 stars, around 170 of these being brighter than magnitude +12,^[3] the brightest of which is HD 225187, a 7th-magnitude B8V star. It has a cross-sectional magnitudal density of about 30 per square parsec: less than half that of the Pleiades cluster. Of the confirmed members, eight have been found to radiate an excess of infrared energy, indicating that they host orbiting debris disks.^[4] Roughly half the stars in the cluster are members of binary star systems; six of the member stars are confirmed spectroscopic binaries.^[5] A system known as NGTS J0002-29 is a triple system that contains one of only a few well-characterised eclipsing binaries with two red dwarfs: they orbit each other with a period of 1.098 days.^[6] There are also some 30–40 brown dwarf members.^[1]

References

1. Moraux, E.; et al. (August 2007), "The lower mass function of the young open cluster Blanco 1: from 30 M_Jup to 3 M_⊙", Astronomy and Astrophysics, 471 (2): 499–513, arXiv:0706.2102, Bibcode:2007A&A...471..499M, doi:10.1051/0004-6361:20066308, S2CID 14759280.
2. Blanco, Victor M. (August 1949), "A New Galactic Star Cluster in Sculptor", Publications of the Astronomical Society of the Pacific, 61 (361): 183, Bibcode:1949PASP...61..183B, doi:10.1086/126171, S2CID 121905502.
3. Bagnall, Philip M. (2012), The Star Atlas Companion: What You Need to Know about the Constellations, Springer, p. 409, ISBN 978-1461408307.
4. Stauffer, John R.; et al. (August 1949), "Debris Disks of Members of the Blanco 1 Open Cluster", The Astrophysical Journal, 719 (2): 1859–1871, arXiv:1007.0239, Bibcode:2010ApJ...719.1859S, doi:10.1088/0004-637X/719/2/1859, S2CID 30296284.
5. González, J. F.; Levato, H. (November 2009), "Spectroscopic study of the open cluster Blanco 1", Astronomy and Astrophysics, 507 (1): 541–547, Bibcode:2009A&A...507..541G, doi:10.1051/0004-6361/200912772.
6. Smith, Gareth D.; Gillen, Edward; Queloz, Didier; Hillenbrand, Lynne A.; Acton, Jack S.; Alves, Douglas R.; Anderson, David R.; Bayliss, Daniel; Briegal, Joshua T.; Burleigh, Matthew R.; Casewell, Sarah L.; Delrez, Laetitia; Dransfield, Georgina; Ducrot, Elsa; Gill, Samuel; Gillon, Michaël; Goad, Michael R.; Günther, Maximilian N.; Henderson, Beth A.; Jenkins, James S.; Jehin, Emmanuël; Moyano, Maximiliano; Murray, Catriona A.; Pedersen, Peter P.; Sebastian, Daniel; Thompson, Samantha; Tilbrook, Rosanna H.; Triaud, Amaury H M J.; Vines, Jose I.; Wheatley, Peter J. (2021). "NGTS clusters survey – III. A low-mass eclipsing binary in the Blanco 1 open cluster spanning the fully convective boundary". Monthly Notices of the Royal Astronomical Society. 507 (4): 5991–6011. arXiv:2109.00836. doi:10.1093/mnras/stab2374.