Astronomy:74 Geminorum
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 39m 28.593s[2] |
| Declination | +17° 40′ 28.28″[2] |
| Apparent magnitude (V) | 5.05[3] |
| Characteristics | |
| Evolutionary stage | K-type giant |
| Spectral type | K5.5III[3] |
| Apparent magnitude (U) | 8.53[3] |
| Apparent magnitude (B) | 6.61[3] |
| Apparent magnitude (G) | 4.348±0.003[3] |
| Apparent magnitude (J) | 2.11[3] |
| Apparent magnitude (H) | 1.32[3] |
| Apparent magnitude (K) | 1.14[3] |
| B−V color index | 1.616±0.007[4] |
| Astrometry | |
| Radial velocity (Rv) | 25.38±0.19[5] km/s |
| Proper motion (μ) | RA: 5.374[2] mas/yr Dec.: -1.199[2] mas/yr |
| Parallax (π) | 5.1083 ± 0.0964[2] mas |
| Distance | 640 ± 10 ly (196 ± 4 pc) |
| Absolute magnitude (MV) | -1.01[1] |
| Details | |
| Radius | 89.6[lower-alpha 1] R☉ |
| Luminosity | 666[7] L☉ |
| Temperature | 3,933[7] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.[6] It has an apparent magnitude of 5.05, making it faintly visible to the naked eye.[1]
Characteristics
Based 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.[3] 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.[6] At the current distance of 163.1 pc (532 light-years), as measured by a Hipparcos parallax of 6.13 milliarcseconds,[4] it gives a physical size of 89.6 R☉.
74 Geminorum has an apparent magnitude of 5.05,[3] making it visible to the naked eye only from locations with dark skies, far from light pollution.[1] The absolute magnitude, i.e. the magnitude of the star if it was seen at 10 parsecs (33 ly), is -1.01.[1] It is located in the coordinates RA Template:Ra, DEC +17° 40′ 28.3″, which is within the Gemini constellation.[3][8] The star is moving away from Earth at a velocity of 25.38 km/s.[5] 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).[3]
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.[6]
See also
Notes
- ↑ From an angular diameter of 6.13 milliarcseconds[6] and a distance of 163.1 parsecs.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 "74 Geminorum - Star in Gemini | TheSkyLive.com". https://theskylive.com/sky/stars/74-geminorum-star.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 "74 Geminorum". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=74+Geminorum.
- ↑ 4.0 4.1 4.2 Template:Cite New HIP red.
- ↑ 5.0 5.1 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. doi:10.1051/0004-6361:20041272. ISSN 0004-6361. Bibcode: 2005A&A...430..165F. Data about this star is available here in VizieR
- ↑ 6.0 6.1 6.2 6.3 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. doi:10.1093/mnras/sty1427. ISSN 0035-8711. Bibcode: 2018MNRAS.478.5683D.
- ↑ 7.0 7.1 7.2 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars" (in en). Monthly Notices of the Royal Astronomical Society 427 (1): 343–357. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. Bibcode: 2012MNRAS.427..343M. Data about this star is available here at VizieR.
- ↑ "Find the constellation which contains given sky coordinates". https://djm.cc/constellation.html.
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