Rho2 Cephei

Short description: Star in the constellation Cepheus

For other stars with this Bayer designation, see ρ Cephei.

Rho2 Cephei

Location of ρ2 Cephei (circled in red)

Observation data
Equinox J2000.0]] (ICRS)
Constellation | Cepheus
Right ascension |  22h 29m 52.97797s[1]
Declination | +78° 49′ 27.4320″[1]
Apparent magnitude (V) | 5.50[2]
Characteristics
Evolutionary stage | main sequence[1][3]
Spectral type | A3 V[4]
U−B color index | +0.07[2]
B−V color index | +0.06[2]
Astrometry
Radial velocity (Rv)| −1.25±0.37[1] km/s
Proper motion (μ)|  RA: +3.543[1] mas/yr
Dec.: −20.840[1] mas/yr
Parallax (π)| 13.6037 ± 0.0544[1] mas
Distance| 239.8 ± 1.0 ly
(73.5 ± 0.3 pc)
Absolute magnitude (MV)| +1.07[5]
Details
Mass| 2.23±0.03[3] M☉
Luminosity| 32[5] L☉
Surface gravity (log g)| 4.2[6] cgs
Temperature| 8,511[3] K
Rotational velocity (v sin i)| 133[7] km/s
Age| 85[6] Myr
Other designations

ρ Cephei, ρ2 Cep, 29 Cephei, BD+78°801, FK5 1593, HD 213798, HIP 111056, HR 8591, SAO 10402[8]

Database references
SIMBAD| data

Rho2 Cephei, Latinized from ρ2 Cephei, or simply ρ Cephei, is a solitary[9] star in the northern constellation of Cepheus. With an apparent visual magnitude of 5.50,[2] it is faintly visible to the naked eye, forming an optical pair with Rho1 Cephei. Based upon an annual parallax shift of 13.6 mas as seen from the Earth, it is located about 240 light years from the Sun.

Rho2 Cephei is an A-type main sequence star with a stellar classification of A3 V,[4] estimated to be 85 million years old. It has a high rate of rotation, showing a projected rotational velocity of 133 km/s.[7] The effective temperature of its photosphere is 8,511 K and its bolometric luminosity, the total amount of radiation it emits at all wavelengths, is 32 L☉.

This star has been called by the Arabic name Al Kalb al Rāʽi, the Shepherd's Dog,[10] which is better known (with the spelling Cebalrai) as a name for β Ophiuchi.

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
2. ↑ 2.0 2.1 2.2 2.3 Oja, T. (April 1983), "UBV photometry of FK4 and FK4 supplement stars", Astronomy and Astrophysics Supplement Series 52: 131–134, Bibcode: 1983A&AS...52..131O.
3. ↑ 3.0 3.1 3.2 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
4. ↑ 4.0 4.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C.
5. ↑ 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
6. ↑ 6.0 6.1 Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (2016). "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars". The Astronomical Journal 152 (2): 40. doi:10.3847/0004-6256/152/2/40. Bibcode: 2016AJ....152...40G.
7. ↑ 7.0 7.1 Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R.
8. ↑ "rho Cep -- Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=rho02+Cep, retrieved 2017-05-05.
9. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
10. ↑ Allen, R. H. (1899), Star Names: Their Lore and Meaning, p. 159, https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Cepheus*.html

* v
* t
* e

Cepheus constellation

Stars (list)|

| Bayer|

* α (Alderamin)
* β (Alfirk)
* γ (Errai)
* δ
* ε
* ζ
* η
* θ
* ι
* κ
* λ
* μ (Garnet Star)
* ν
* ξ (Kurhah)
* ο
* π
* ρ1
* ρ2

|

Flamsteed|

* 4
* 6
* 7
* 9
* 11
* 12
* 13
* 14
* 15
* 16
* 18
* 19
* 20
* 24
* 25
* 26
* 30
* 31
* 77 Dra
* 78 Dra
* 79 Dra
* 80 Dra
* 2 UMi

Variable|

* S
* T
* U
* V
* W
* RW
* RZ
* SV
* VV
* VW
* WX
* WZ
* XX
* XZ
* ZZ
* AH
* AK
* BH
* BO
* CP
* CQ
* CR
* CW
* CX
* DH
* DI
* DO
* DQ
* EE
* EG
* EI
* EK
* EM
* GP
* GW
* IL
* IR
* IV
* NY
* OV
* PQ
* PV
* V350
* V354
* V368
* V374
* V379
* V380
* V381
* V388
* V398
* V408
* V414
* V419
* V421
* V422
* V426
* V431
* V438
* V444
* V458

HR|

* 20
* 55
* 158
* 240
* 306
* 312
* 333
* 357
* 386
* 572
* 597
* 774
* 881
* 906
* 961
* 965
* 1107
* 1304
* 1317
* 1523
* 1616
* 1885
* 7742
* 7925
* 7938
* 7955
* 7967
* 7993
* 8029
* 8043
* 8049
* 8065
* 8099
* 8119
* 8133
* 8150
* 8168
* 8174
* 8179
* 8226
* 8239
* 8243
* 8281
* 8312
* 8327
* 8342
* 8347
* 8357
* 8374
* 8375
* 8384
* 8388
* 8395
* 8442
* 8472
* 8474
* 8476
* 8479
* 8483
* 8490
* 8493
* 8506
* 8535
* 8537
* 8546
* 8557
* 8568
* 8595
* 8598
* 8599
* 8625
* 8677
* 8683
* 8687
* 8696
* 8702
* 8707
* 8736
* 8745
* 8748
* 8779
* 8808
* 8811
* 8844
* 8867
* 8918
* 8938
* 8952
* 8971
* 8972
* 9005
* 9013
* 9038
* 9104

HD|

* 12918
* 12927
* 25904
* 200775
* 204521
* 204827
* 207538
* 207826
* 208132
* 208392
* 212136
* 215588
* 217903
* 224890

Gliese|

* Gliese 48
* Gliese 809
* GJ 1277

Other|

* Cepheus A HW 2
* Cepheus X-4
* IRAS 21391+5802
* Kruger 60
* NGC 7538 IRS 1
* NGC 7538 IRS 9
* OH 104.9+2.4
* PSR B2224+65
* PSR J2229+6114
* S140 IRS 1
* TYC 3980-1081-1
* 4U 2206+54
* WISE 0313+7807
* WR 152
* WR 156

Star clusters|

| Association|

* Cepheus OB2
* Cepheus OB3
* Cepheus OB4

|

Open|

* NGC 188
* NGC 6939
* NGC 7023
* NGC 7129
* NGC 7142
* NGC 7160
* NGC 7226
* NGC 7234
* NGC 7261
* NGC 7281
* NGC 7380
* NGC 7419
* NGC 7423
* NGC 7429
* NGC 7510
* NGC 7762
* S 140
* Trumpler 37

Globular|

* Palomar 1

Molecular clouds|

* Cepheus A
* Cepheus B
* Cepheus C

Nebulae|

| Dark|

* Barnard 150
* CB 244
* Elephant's Trunk Nebula
* IC 1396N
* L1157
* L1228

|

H II|

* IC 1396
* NGC 7538
* NGC 7822
* S 128
* S 140
* S 155
* S 156

Reflection|

* Ghost Nebula
* Iris Nebula
* NGC 7129
* VdB 157

Planetary|

* NGC 40
* NGC 7076
* NGC 7139
* NGC 7354

SNR|

* CTA 1
* SSTGFLS J222557+601148

Galaxies|

| NGC|

* 1184
* 1544
* 2276
* 2300
* 6949
* 6952

|

Other|

* 3C 61.1
* 3C 427.1
* 4C +74.26
* QSO B2021+614
* S5 0014+81

Other|

* GRB 980519
* SN 2008S

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