  | |
| Observation data EpochJ2000[1] EquinoxJ2000[1] | |
|---|---|
| Constellation | Vela |
| HR 3562A | |
| Right ascension | 08h 55m 19.20215s |
| Declination | −45° 02′ 30.0241″ |
| Apparent magnitude (V) | +6.26[2] |
| HR 3562B | |
| Right ascension | 08h 55m 21.6s[3] |
| Declination | −45° 02′ 52″[3] |
| Apparent magnitude (V) | +12.639[4] |
| Characteristics | |
| HR 3562A | |
| Spectral type | A3IV[5] |
| U−Bcolor index | −0.63[2] |
| B−Vcolor index | −0.16[2] |
| J−Hcolor index | −0.121[6] |
| J−Kcolor index | −0.132[6] |
| Variable type | Slowly pulsating B-type star |
| Astrometry | |
| HR 3562A | |
| Radial velocity (Rv) | 22.0±3.3[7] km/s |
| Proper motion (μ) | RA: -13.091[8]mas/yr Dec.: 7.601[8]mas/yr |
| Parallax (π) | 2.6833±0.0455 mas[8] |
| Distance | 1,220 ± 20 ly (373 ± 6 pc) |
| Absolute magnitude (MV) | −2.55[4] |
| HR 3562B | |
| Absolute magnitude (MV) | 5.22[4] |
| Orbit[4] | |
| Primary | HR 3562A |
| Companion | HR 3562B |
| Semi-major axis (a) | 35.0" (10024 AU) |
| Details[4] | |
| HR 3562A | |
| Mass | 5.644±0.282[5] M☉ |
| Radius | 5.648±0.282[5] R☉ |
| Luminosity | 832 L☉ |
| Surface gravity (log g) | 3.67or 4.01 cgs |
| Temperature | 16,982 K |
| Rotational velocity (v sin i) | 5[9] km/s |
| Age | 36-38 Myr |
| HR 3562B | |
| Luminosity | 0.64[a] L☉ |
| Temperature | 5,613 K |
| Age | 50-110 Myr |
| Other designations | |
| WDS 08553-4503AB | |
| HR 3562A:IY Velorum,CD−44° 4951,CPD−44° 3226,Gaia DR3 5331355759365786368,GC 12349,HD 76566,HIP 43807,HR 3562A,SAO 220664,PPM 313785,WDS J08553-4503A,TIC 30125083,TYC 8152-139-1,GSC 08152-00139,2MASS J08551918-4502298[1] | |
| HR 3562B:CD−44° 4951B,CPD−44° 3226B,HD 76566B,WDS J08553-4503B[3] | |
| Database references | |
| SIMBAD | A |
| B | |
HR 3562 (HD 76566) is avisual binary consisting of a bluish-white huedvariable star and aSun-like secondary star in the southernconstellation ofVela. It has thevariable-star designationIY Velorum (abbreviated to IY Vel). With anapparent magnitude of 6.26, the brighter primary is near the limit fornaked eye visibility. The fainter companion has an apparent magnitude of 12.639[4] and can be observed with atelescope with anaperture of 76 mm or wider.[10] It is located approximately 373 parsecs (1,220 ly) distant according toGaia EDR3parallax measurements, and is receding away from theSolar System at a heliocentricradial velocity of 22.0 km/s.
This is a hot, luminousB-typesubgiant (spectral type B3IV) with a mass of 5.644M☉ and a radius of 5.648R☉.[5] It radiates 832 times theluminosity of the Sun from itsphotosphere at aneffective temperature of 16,982 K (16,709 °C; 30,108 °F), almost three times hotter than theSun (5,772 K). It is thought to be very young at around 36-38 million years old.[4]
In 1982, Burki et al. reported that the star showed pulsations with multiple periods, namely 1.97 days, 1.73 days, and 1.66 days, all withamplitudes of severalmmag that produce a combined peak-to-peak amplitude of about 0.04 mag. As such, they categorized the star as a multiperiodicslowly pulsating B-type star (SPB).[12] In 1986, however, Balona & Laing were only able to confirm one major period of 2.22 days. Due to the small projectedrotational velocity, they classified it as arotating ellipsoidal variable instead, which would have been indicative of a close binary with anorbital period of 4.44 days.[9] Further observations were conducted by Balona, who, in 1994, changed his position and concluded that the star was indeed a SPB, having discovered that the 2.22 day period he previously found was actually the mean of three distinct periods at 1.9566 days, 2.1072 days, and 2.4563 days. It shows similarities toHR 2680, another SPB.[13]
HR 3562 was first discovered to be adouble star byJohn Herschel in 1836.[14] In 2001, it was confirmed that this was a physicalbinary system rather than an optical double i.e., a pair of unrelated stars closely aligned by chance. The pair are spaced 10,024 AU (0.15850 ly) apart, based on the separation of 35.0arcseconds. This secondary is a post-T Tauri star, currently in themain sequence, with a Sun-like mass (0.98-1.01M☉) and a slightly cooler temperature of 5,613 K (5,340 °C; 9,644 °F), emitting 64% the Sun's luminosity. The star is aged about 50-110 million years.[4]
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