74 Geminorum (f Geminorum) is a K-type giant star in the constellation Gemini. It is located about 640 light-years from Earth based on its Gaia DR3 parallax. The star is often subject to lunar occultations, allowing an accurate measurement of its angular diameter.[1] It has an apparent magnitude of 5.05, making it faintly visible to the naked eye.[2]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 39m 28.593s[3] |
| Declination | +17° 40′ 28.28″[3] |
| Apparent magnitude (V) | 5.05[4] |
| Characteristics | |
| Evolutionary stage | K-type giant |
| Spectral type | K5.5III[4] |
| Apparent magnitude (U) | 8.53[4] |
| Apparent magnitude (B) | 6.61[4] |
| Apparent magnitude (G) | 4.348±0.003[4] |
| Apparent magnitude (J) | 2.11[4] |
| Apparent magnitude (H) | 1.32[4] |
| Apparent magnitude (K) | 1.14[4] |
| B−V color index | 1.616±0.007[5] |
| Astrometry | |
| Radial velocity (Rv) | 25.38±0.19[6] km/s |
| Proper motion (μ) | RA: 5.374 mas/yr[3] Dec.: -1.199 mas/yr[3] |
| Parallax (π) | 5.1083 ± 0.0964 mas[3] |
| Distance | 640 ± 10 ly (196 ± 4 pc) |
| Absolute magnitude (MV) | -1.01[2] |
| Details | |
| Radius | 89.6[a] R☉ |
| Luminosity | 666[7] L☉ |
| Temperature | 3,933[7] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Characteristics
editBased on its spectral type of K5.5III, it is a star that has left the main sequence and evolved into a K-type giant star.[4] It radiates about 670 times the solar luminosity from its photosphere at an effective temperature of 3,933 K.[7] The angular diameter, as measured by a lunar occultation, is 3.12±0.06 milliarcseconds.[1] At the current distance of 163.1 pc (532 light-years), as measured by a Hipparcos parallax of 6.13 milliarcseconds,[5] it gives a physical size of 89.6 R☉.
74 Geminorum has an apparent magnitude of 5.05,[4] making it visible to the naked eye only from locations with dark skies, far from light pollution.[2] The absolute magnitude, i.e. the magnitude of the star if it was seen at 10 parsecs (33 ly), is -1.01.[2] It is located in the coordinates RA 07h 39m 28.59s, DEC +17° 40′ 28.3″, which is within the Gemini constellation.[4][8] The star is moving away from Earth at a velocity of 25.38 km/s.[6] f Geminorum is the star's Bayer designation. Other designations for the star include 74 Geminorum (the Flamsteed designation), HIP 37300 (from the Hipparcos catalogue), HR 2938 (from the Bright Star Catalogue) and HD 61338 (from the Henry Draper Catalogue).[4]
The star is often subject to lunar occultations. One of these occultations were observed by the SAO RAS 6-m telescope, which allowed the angular diameter of 74 Geminorum to be accurately measured at 3.12±0.06 milliarcseconds.[1]
See also
editNotes
edit- ^ From an angular diameter of 6.13 milliarcseconds[1] and a distance of 163.1 parsecs.[5]
References
edit- ^ a b c d Dyachenko, V.; Richichi, A.; Balega, Yu; Beskakotov, A.; Maksimov, A.; Mitrofanova, A.; Rastegaev, D. (2018-08-01). "Lunar occultation observations at the SAO RAS 6-m telescope". Monthly Notices of the Royal Astronomical Society. 478 (4): 5683–5688. Bibcode:2018MNRAS.478.5683D. doi:10.1093/mnras/sty1427. ISSN 0035-8711.
- ^ a b c d e "74 Geminorum - Star in Gemini | TheSkyLive.com". theskylive.com. Retrieved 2024-05-05.
- ^ a b c d 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.
- ^ a b c d e f g h i j k l "74 Geminorum". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 5, 2024.
- ^ a b c van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361. Hipparcos record for this source at VizieR.
- ^ a b Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005-01-01). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. ISSN 0004-6361. Data about this star is available here in VizieR
- ^ a b c McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. Data about this star is available here at VizieR.
- ^ "Find the constellation which contains given sky coordinates". djm.cc. Retrieved 2024-05-05.