Platais 8

Platais 8
Observation data (J2000.0 epoch)
Right ascension	09h 06m 52.3s [1]
Declination	−58° 41′ 06″ [1]
Distance	440±1  ly (134.9±0.6  pc [1] )
Apparent dimensions (V)	3.45° × 3.45° [1]
Physical characteristics
Mass	546+265 −178 [2]   M☉
Radius	37.2 ± 4.9  ly (11.4 ± 1.5  pc) [2]
Estimated age	60±15  Ma [3]
Other designations	Platais 8, HIP 45080 Cluster, MWSC 1629
Associations
Constellation	Carina
See also: Open cluster, List of open clusters

Platais 8, also known as the a Carinae cluster or HIP 45080 Cluster is a small and faint open cluster located in the southern constellation Carina. It is estimated to be 440 light years distant based on parallax measurements. ^[1]

The cluster was first noticed by astronomer Imants Platais in 1998. ^[4] A 2005 paper suggests that Platais 8 might have formed near the area where the Scorpius-Centaurus association is located. ^[5] The SIMBAD database lists the cluster having 28,185 members ^[6] but the majority of the stars are field stars. In fact, there are only 32 members physically associated with the cluster. ^[1] The cluster has a combined mass of 546  M_☉ and a radius of 37.2 light years. Platais 8 is rather young, with an age of only 60 million years. ^[3]

Members

These are the members of the cluster as identified by Canat-Gaudin et al. (2018)

Members of Cl Platais 8 ^[7]

Name	mv	MK Type	Dist. (ly)	Notes
HD 76230	6.57	A0 V	410	Binary
HD 78802	7.33	A2 IV	467
HD 76413	7.48	A3 V	417
HD 80628	7.57	A0/1 V	442
HD 78761	7.68	A2 V	454
HD 78027	7.88	A1 V	444

The cluster also has one potential stream star located in Volans ^[1] and was considered to be a background object prior to 2020.

Name	mv	MK Type	Dist. (ly)	Notes
HD 71863	5.94	G8/K0 III	421	HR 3346

References

1. Cantat-Gaudin, T.; Anders, F. (January 2020). "Clusters and mirages: cataloguing stellar aggregates in the Milky Way". Astronomy & Astrophysics. 633: A99. arXiv: 1911.07075 . Bibcode:2020A&A...633A..99C. doi: 10.1051/0004-6361/201936691 . ISSN   0004-6361.
2. Piskunov, A. E.; Schilbach, E.; Kharchenko, N. V.; Röser, S.; Scholz, R.-D. (26 March 2007). "Towards absolute scales for the radii and masses of open clusters". Astronomy & Astrophysics. 468 (1): 151–161. arXiv: astro-ph/0702517 . Bibcode:2007A&A...468..151P. doi: 10.1051/0004-6361:20077073 . eISSN   1432-0746. ISSN   0004-6361.
3. Vande Putte, D.; Garnier, T. P.; Ferreras, I.; Mignani, R. P.; Cropper, Mark (6 September 2010). "A kinematic study of open clusters: implications for their origin". Monthly Notices of the Royal Astronomical Society. 407 (4): 2109–2121. arXiv: 0912.0695 . Bibcode:2010MNRAS.407.2109V. doi: 10.1111/j.1365-2966.2010.17025.x . ISSN   0035-8711.
4. Platais, Imants; Kozhurina-Platais, Vera; van Leeuwen, Floor (November 1998). "A Search for Star Clusters from the ]Hipparcos Data". The Astronomical Journal. 116 (5): 2423–2430. Bibcode:1998AJ....116.2423P. doi: 10.1086/300606 . ISSN   0004-6256.
5. Piskunov, A. E.; Kharchenko, N. V.; Röser, S.; Schilbach, E.; Scholz, R.-D. (16 December 2005). "Revisiting the population of Galactic open clusters". Astronomy & Astrophysics. 445 (2): 545–565. arXiv: astro-ph/0508575 . Bibcode:2006A&A...445..545P. doi: 10.1051/0004-6361:20053764 . eISSN   1432-0746. ISSN   0004-6361.
6. "Cl Platais 8". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 7 January 2021.
7. Cantat-Gaudin, T.; Jordi, C.; Vallenari, A.; Bragaglia, A.; Balaguer-Núñez, L.; Soubiran, C.; Bossini, D.; Moitinho, A.; Castro-Ginard, A.; Krone-Martins, A.; Casamiquela, L.; Sordo, R.; Carrera, R. (October 2018). "A Gaia DR2 view of the open cluster population in the Milky Way". Astronomy & Astrophysics. 618: A93. arXiv: 1805.08726 . Bibcode:2018A&A...618A..93C. doi: 10.1051/0004-6361/201833476 . ISSN   0004-6361.